11th semester II GSEB Board paper 2016, Biology Solution , Set – 18, PART A(OBJECTIVE) 30-03-2016

Objective paper is solved in this post…look in next post for subjective solution.

11th semester II GSEB Board paper 2016

Biology

Set – 18

 Part A

  1. The thick filaments are made up of which protein?

(A)  Myosin                    (B)  Actin                        (C)  Troponin              (D)  Tropomyosin     

Ans: (A) Myosin

       

  1. The cartilage present in the pubis of frogs, in suprascapula and at head of humerus and femur.

(A)  White fibro cartilage.                                        (B)  Calcified cartilage.

(C)  Yellow elastic cartilage.                                   (D)  Hyaline cartilage.

Ans: (B) Calcified cartilage. 

  1. Match the following and choose the correct option.

 

Column-I Column-II
(P) Endomysium

(Q) Synapse

(R) Nissl’s granules

(S) Schwann’s cell

(i)  The physical gap between the axon nerve ending and dendrites nerve endings.

(ii) The spaces between the cardiac muscle cells.

(iii) Neurilemma sheath made up of single layer of flat cells.

(iv) Large numbers of dark particles present in cyton.

(A) (P–ii), (Q–i), (R–iii), (S–iv)

(B) (P–iv), (Q–ii), (R–iii), (S–i)

(C) (P–ii), (Q–i), (R–iv), (S–iii)

(D) (P–iii), (Q–iv), (R–ii), (S–i)

Ans: (C) (P–ii), (Q–i), (R–iv), (S–iii)       

  1. Pseudo-stratified epithelium is seen in?

(A)  Pancreatic duct                                               (B)  Oesophagus

(C)  Inner lining of trachea                                 (D)  Uriniferous tubule 

Ans: (C) Inner lining of trachea

 

  1. The cells are irregular in shape and contain three active substances – Heparin, histamine and Serotonin, are called as……

(A)  Mast cells                (B)  Phagocytic cells       (C) Fibroblast          (D) Histocytes 

Ans: (A) Mast cells       

 

  1. ……type of placentation has false septum in ovary.

(A)    Axile                       (B)    Marginal                 (C)    Free central                (D) Parietal 

Ans: (D) Parietal 

  1. In what fashion, new flowers are arranged in Raceme inflorescence?

(A)  None of the given three potions                   (B)  Centripetal
(C) Acropetal                                                               (D) Acropetal and Centripetal.

Ans: (C) Acropetal       

 

  1. Spathe is found in which of the following inflorescence?

(A)  Spike                       (B)  Umbel                      (C)  Catkin                  (D)  Spadix 

Ans: (D) Spadix       

 

  1. The smallest petals in vexillary aesfciyatiori are known as……
    (A) Standard and Alae.                                         (B)  Standard

(C)  Alae                                                                 (D)  Keel 

Ans: (D) Keel       

 

  1. Xylem parenchyma are living cells and they store which substances ?

(A) Starch, resin, lipid and crystalline substances.

(B)   Starch, resin, mucilage and latex.

(C)  Starch, lipid, tannin and crystalline substances.

(D)  Starch, lipid, latex and crystalline substances. 

Ans: (C) Starch, lipid, tannin and crystalline substances. 

 

  1. Statment X – The vascular bundles, in which, xylem and phloem occur together, are called conjoint vascular bundles

Statement Y – These vascular bundles are of three types.

(A)  Statement X and Statement Y are wrong.

(B)  Statement X and Y both are correct.

(C)  Statement X is correct but Y is wrong.

(D)  Statement X is wrong but Y is correct. 

Ans: (B) Statement X and Y both are correct. 

  1. What does ‘X’ and ‘Y’ indicate in the given figure?

1.jpg

(A)  Muscle and bone.                                             (B)  Ligament and tendon

(C)  Ligament and bone                                           (D)  Ligament and muscle.

 Ans: (B) Ligament and tendon

 

  1. Match the following and choose the correct option.
Column-I (Cells) Column-II (Position)
(P) Guard cells

(Q) Motor cells

(R) Resin duct

(S) Casparian strips

(i)  In endodermis of dicot root.

(ii)  In cortex of dicot stem.

(iii) In upper epidermis of monocot leaf

(iv) In epidermis of aerial part’s surrounding stomata.

(A)  (P-iii), (Q-iv), (R-i), (S-i)

(B)  (P-iv), (Q-iii), (R-ii), (S-i)

(C)  (P-ii), (Q-iii), (R-i), (S-iv)

(D)  (P-iv), (Q-ii), (R-iii), (S-i)

Ans: (B) (P-iv), (Q-iii), (R-ii), (S-i)

       

  1. Malpighian body is made up of…….

(A)  Bowman’s capsule arid efferent arteriole.

(B)  Bowman’s capsule and afferent arteriole.

(C) Bowman’s capsule and capillary network.

(D) Bowman’s capsule and Glomerulus.

Ans: (D)Bowman’s capsule and Glomerulus

 

  1. The meristem located between permanent tissues in grasses, is known as …….

(A)  Cambium                                                        (B)  Apical meristem

(C)  Intercalary meristem                                  (D) Lateral meristem

Ans: (C) Intercalary meristem

 

  1. Which one of the following is not suitable according to the structure?
    (A) Enterokinase            (B) Enterocrinin         (C) Secretin                (D) Cholecystokinin

Ans: (A) Enterokinase   

       

  1. In Frog, deoxygenated blood from different parts of the body is collected in heart by….

(A)  Left auricle             (B)  Ventricle                  (C)   Aortic trunk     (D) Sinus venosus

Ans: (D) Sinus venosus

 

  1. By which of the following arteries, the dorsal aorta is formed?

(A)  One carotid arch and one systemic arch.      (B)  Two carotid arch.

(C)  Two systemic arch                                          (D)   Two pulmocutaneous arch

Ans: (C) Two systemic arch

       

  1. Statement A – Liver is not considered as true digestive gland.
    Reason R – It only emulsifies fat.

(A)  Statement A is false and R is true.

(B)  Statement A and R both are true, R is the explanation of A.

(C)  Statement A and R both are true; R is not correct explanation of A.

(D)  Statement A is true and R is false.

Ans: (B) Statement A and R both are true, R is the explanation of A.

       

  1. Which enzyme is present in gastric juice?
    (A) Lipase                              (B)  Trypsin                     (C)  Amylase               (D)  Pepsinogen 

Ans: (D) Pepsinogen

 

  1. Of the following given statements, which is correct one?

      (X)       Frog skin protects the body against foreign bodies and algae.

      (Y)       The stratum compactum is made by dense, connective tissue, Smooth muscle fibres, nerves and Blood vessels.

      (Z)       The stratum spongiosum is made by dense connective tissue, smooth muscle fibres and mucous glands.

      (A)   Y                            (B)    X and Z                             (C)    Y and X               (D) Z 

Ans: (A) Y 

 

  1. If ‘P’ indicated in the diagram is removed, the transport of which juice will stop?

1

(A)       Intestinal juice    (B)    Gastric juice                    (C)  Pancreatic juice    (D)  Bile juice 

Ans: (D) Bile juice

     

  1. In Sorosis, which part unite together to make fruits?

(A)       Petals and Persistant hairy calyx.

(B)          Bracts and Ovary

(C)       Bracts and Petals

(D)          Rachis and Bracts. 

Ans: (D) Rachis and Bracts.

       

  1. Match the following and choose the correct option.
Column-I Column-II
(P) Perianth

(Q) Hypogynbus flower

(R) Epigynous flower

(S) Perigynous flower

(i) Rose

(ii) Sunflower

(iii) Datura

(iv) Bougainvillea

(A)       (P-iv), (Q-iii), (R-ii), (S-i)                            (B)  (P-iii), (Q-iv), (R-i), (S-ii)

(C)       (P-iii), (Q-ii), (R-iv), (S-i)                            (D)  (P-iv), (Q-ii), (R-iii), (S-i)

Ans: (A) (P-iv), (Q-iii), (R-ii), (S-i)

     

  1. In which fruit, Pericarp and seed coat are free from one another?
    (A) Achene           (B)    Caryopsis                        (C)  Nut                      (D) Samara

Ans: (A) Achene

       

  1. Where the true fruit is situated in apple?

(A)       Above the thalamus.                                   (B)  True fruit is not formed.

(C)       Outside the thalamus.                                  (D)  Inside the thalamus.

Ans: (D) Inside the thalamus.

       

  1. Give the correct labeling of a, b and c shown in the given figure

 

1.jpg

(A)       a – Lenticel, b – Secondary cork, c – Cork cambium.

(B)       a – Lenticel, b – Cork cambium, c – Secondary cork

(C)       a – Cork cambium, b – Cork, c – Cambium

(D)          a – Lenticel, b – Cork, c – Secondary cork 

Ans: (B) a – Lenticel, b – Cork cambium, c – Secondary cork

       

  1. Which structure is formed due to joining of intra–fascicular and inter–fascicular cambium?

      (A)       Casparian strips                                         (B)  Annual rings

      (C)       Vascular cambium                            (D)  Cambium ring.

Ans: (D) Cambium ring

       

  1. In the vascular bundle of which plant organ, phloem parenchyma is absent and water containing lysigenous cavities are present?

(A)       Monocot stem                                 (B)  Monocot root
(C)       Dicot stem                                        (D)  Dicot root

Ans: (A) Monocot stem

       

  1. The tissue which is absent in monocots and underground parts of the plants….

(A)       Xylem                (B)  Parenchyma         (C) Sclerenchyma   (D) Collenchyma 

Ans: (D) Collenchyma

       

  1. The frog undergoes dormant life during winter season is known as……

(A)       All the given three options.                   (B)  Aestivation
(C)       Hibernation                                                 (D)  Aestivation and hibernation. 

Ans: (C) Hibernation        

       

  1. Which figure shows labium in the following figures?

(A)1.jpg

(B)     1.jpg

(C) 1

(D)   1

Ans: (C)1

        

  1. The nervous system of Pheritima posthuma is located on which side?
        (A) Both Dorsal and Ventral side                 (B) Dorsal

      (C) Ventral                                                             (D) Lateral 

Ans: (C) Ventral

       

  1. In Cockroach walking legs, the femur is located between?
    (A) Tibia and tarsus                                         (B)  Coxa and trochanter

(C)       Trochanter and tibia                         (D)  Trochanter and tarsus. 

Ans: (C) Trochanter and tibia                       

       

  1. The cells of which region of root differentiates and form tissue

(A)       Region of elongation                                 (B)  Meristematic region

(C)       Region of maturation                                 (D)  Root cap.

Ans: (C) Region of maturation

 

  1. Which type of phyllotaxy is observed in Guava?

(A)       Alternate                                                     (B)  Whorled

(C)        Opposite decussate                                    (D)  Opposite superimposed. 

Ans: (D) Opposite superimposed.       

 

  1. In Bignonia, hook like or clawed structure is the modification of.

(A)       Petiole                (B)  Stipule                (C) Leaflets                (D)  Leaf 

Ans: (C) Leaflets

       

  1. Which part of the plant is modified in runner for vegetative propagation?

(A)       Internode       (B) Auxiliary bud          (C)  Apical bud          (D)  Floral bud 

Ans: (A) Internode

       

  1. Which is not suitable for the sense organs of Cockroach?

(A)       Anal circus         (B)  Antennae                  (C)  Anal styles      (D)  Maxillary palp. 

Ans: (C) Anal styles

       

  1. Calciferous glands are found in which segment of earthworm

(A)       1st to 7th segment                                        (B)         5th to 7th segment.
(C)       5th to 9|h segment                                             (D)         9th to l4th segment 

Ans: (D) 9th to l4th segment

       

  1. Which animal is used as bait in Fishing?

(A)     Earthworm       (B)  Butterfly                  (C)  Cockroach           (D) Salamander

Ans: (A) Earthworm      

       

  1. In the given diagram, what indicates typhlosole?

1.jpg

(A)       Y                        (B)  X

(C)       Z                         (D)  W 

Ans: (A) Y / (C) Z (Both answers are right, but according to labelling in textbook, Y might be the right one)

 

  1. Which modification is observed in Pea for special functions?
    (A) For all the special functions.                     (B) Symbiosis

(C)       Photosynthesis.                                          (D)  Climbing.

Ans: (A) For all the special functions.

       

  1. Match the following and choose the correct option.
Column-I Column-II
(P)  Sheathing leaf base

(Q) Tunicated bulb

(R)  Foliaceous stipule

(S)  Phylloclade

(i)  Pea

(ii)  Opuntia

(iii)  Onion

(iv)  Maize

(A)       (P-i), (Q-iii), (R-iv), (S-ii)

(B)       (P-iv), (Q-iii), (R-ii), (S-i)

(C)       (P-iv), (Q-ii), (R-iii), (S-i)

(D)       (P-iv), (Q-iii), (R-i), (S-ii) 

Ans: (D) (P-iv), (Q-iii), (R-i), (S-ii)

       

  1. Corm is condensed form of ………. It is a food storing structure made up of only one……

(A)       Tuber, Internode                                        (B)  Tuber, Node.

(C)        Rhizome, Node.                                         (D)  Rhizome, Internode. 

Ans: (D) Rhizome, Internode.

       

  1. Breathing roots are considered as…….

(A)       Fibrous, positive geotropic, positive phototropic.

(B)       Normal root, negatively geotropic, positive phototropic.

(C)       Normal root, positive geotropic, positive phototropic

(D)       Fibrous, negatively geotropic, positive phototropic. 

Ans: (B) Normal root, negatively geotropic, positive phototropic.

 

  1. Which grains are stored in aleurone layer of monocot seed?

(A)       Glycogen            (B)  Starch                 (C)  Lipid                    (D) Protein 

Ans: (D) Protein

       

  1. From where the embryo get nourishment in non-endospermic seed during seed germination?

(A)          From Cotyledons                                       (B)   From Endosperm

(C)        From Sunlight                                              (D) From Micropyle. 

Ans: (A)      From Cotyledons    

       

  1. The bodywall of the earthworm is made up of……

(A)       Cuticle – scaly layer – longitudinal muscles

(B)       Cuticle – circular muscles – parietal layer

(C)       Cuticle – skeletal muscles – scaly layer.

(D)       Cuticle – scaly layer – parietal layer. 

Ans: (B) Cuticle – circular muscles – parietal layer

       

  1. Seed is attached to the fruit by which of the following structure?

(A)       Cotyledons         (B)  Seed coat                 (C)   Seed pore             (D)           Hilum 

Ans: (D) Hilum

       

 

printable pdf file is also available in link, given below…

11th semester II GSEB Board paper 2016

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CH 5 – MORPHOLOGY OF FLOWERING PLANTS

NCERT NOTES OF MORPHOLOGY OF FLOWERING PLANTS

CHAPTER 5

MORPHOLOGY OF FLOWERING PLANTS

  • Angiosperms are characterized by presence of roots, stems, leaves, flowers and fruits.
  • The underground part of the flowering plant is the root system while the portion above the ground forms the shoot system.

 1

THE ROOT

  • Roots are developed from Radicle of the embryo of a germinating seed.
  • In majority of the dicotyledonous plants, the direct elongation of the radicle leads to the formation of primary root which grows inside the soil. It bears lateral roots of several orders that are referred to as secondary, tertiary, etc. roots. The primary roots and its branches constitute the tap root system.

e.g., mustard plant.

  • In monocotyledonous plants, the primary root is short lived and is replaced by a large number of roots. These roots originate from the base of the stem and constitute the fibrous root system.

e.g., wheat plant.

  • In some plants, like grass, Monstera and the banyan tree, roots arise from parts of the plant other than the radicle and are called adventitious roots.
  • The main functions of the root system are –
    • Absorption of water and minerals from the soil,
    • providing a proper anchorage to the plant parts,
    • storing reserve food material and
    • synthesis of plant growth regulators.

1.jpg

 

Regions of the Root

  1. Root cap – The root apex is covered by a thimble-like structure called the root cap. It protects the tender apex of the root as it makes its way through the soil.
  2. Region of meristematic tissue – it is present a few millimeters above the root cap. The cells of this region are very small, thin-walled and with dense protoplasm. They divide repeatedly.
  3. Region of root elongation – The cells of this region undergo rapid elongation and enlargement and are responsible for the growth of the root in length.
  4. Region of maturation – The cells of this zone gradually differentiate and mature. From this region some of the epidermal cells form very fine and delicate, thread-like structures called root hairs. These root hairs absorb water and minerals from the soil.

Modifications of Root

Roots in some plants change their shape and structure and become modified to perform functions other than absorption and conduction of water and minerals.

  • Modification for food storage –

Tap roots of carrot, turnips and adventitious roots of sweet potato, get swollen and store food.

  • Modification for support –

Prop roots – vertically downward roots originates from heavy branches to support them.

e.g., banyan tree.

Stilt roots – oblique downward roots coming out of the lower nodes of the stem to support weak stem.

e.g., Maize, sugarcane.

  • Modification for respiration –

In some plants growing in swampy areas, many roots come out of the ground and grow vertically upwards. Such roots, called pneumatophores, help to get oxygen for respiration.

e.g, Rhizophora.1.jpg

THE STEM

  • The stem is the ascending part of the axis bearing branches, leaves, flowers and fruits.
  • It develops from the plumule of the embryo of a germinating seed.
  • The stem bears nodes and internodes. The region of the stem where leaves are born are called nodes while internodes are the portions between two nodes.
  • The stem bears buds, which may be terminal or axillary.
  • The main functions of the stem are –
    • spreading out branches bearing leaves, flowers and fruits.
    • conducts water, minerals and photosynthates.
    • Some stems perform the function of storage of food, support, protection and of vegetative propagation.

Modifications of Stem

  • Modification for food storage –

Underground stems of potato, ginger, turmeric, zaminkand, Colocasia are modified to store food in them. They also act as organs of perenation to tide over conditions unfavourable for growth.

  • Modification for support –

Stem tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb such as in gourds (cucumber, pumpkins, watermelon) and grapevines.

  • Modification for defense –

Axillary buds of stems may also get modified into woody, straight and pointed thorns. Thorns are found in many plants such as Citrus, Bougainvillea. They protect plants from browsing animals.

  • Modification for photosynthesis (phylloclade)–

Some plants of arid regions modify their stems into flattened (Opuntia), or fleshy cylindrical (Euphorbia) structures. They contain chlorophyll and carry out photosynthesis.

  • Modification for vegetative propagation –

Runner Underground stems of some plants spread to new niches and when older parts die new plants are formed. e.g., grass and strawberry

Stolon In these plants a slender lateral branch arises from the base of the main axis and after growing aerially for some time arch downwards to touch the ground. e.g., mint and jasmine

Offset A lateral branch with short internodes and each node bearing a rosette of leaves and a tuft of roots is found in aquatic plants. e.g., Pistia and Eichhornia.

Suckerin these, the lateral branches originate from the basal and underground portion of the main stem, grow horizontally beneath the soil and then come out obliquely upward giving rise to leafy shoots. e.g., banana, pineapple and Chrysanthemum.

1

THE LEAF

  • The leaf is a lateral, generally flattened structure borne on the stem.
  • It develops exogenously at the node and bears a bud in its axil – the axillary bud, which later develops into a branch.
  • Leaves originate from shoot apical meristems and are arranged in an acropetal order.
  • They are the most important vegetative organs for photosynthesis.

Parts of leaf

A typical leaf consists of three main parts:

  1. Leaf base – The leaf is attached to the stem by the leaf base and may bear two lateral small leaf like structures called stipules.

In monocotyledons, the leaf base expands into a sheath covering the stem partially or wholly – Sheathing leaf base.

In some leguminous plants the leaf base may become swollen – Pulvinus leaf base.

  1. Petiole – The petiole helps hold the blade to light. Long thin flexible petioles allow leaf blades to flutter in wind, thereby cooling the leaf and bringing fresh air to leaf surface.
  2. Lamina – The lamina or the leaf blade is the green expanded part of the leaf with veins and veinlets. There is, usually, a middle prominent vein, which is known as the midrib. Veins provide rigidity to the leaf blade and act as channels of transport for water, minerals and food materials.

1.jpg

Venation

The arrangement of veins and the veinlets in the lamina of leaf is termed as venation.

  1. Reticulate venation When the veinlets form a network. e.g., Dicotyledons.
  2. Parallel venation When the veins run parallel to each other within a lamina. e.g., Monocot.

1.jpg

Types of Leaves

  1. Simple leaf when lamina of a leaf is entire or when incised, the incisions do not touch the midrib.
  2. Compound leaf When the incisions of the lamina reach up to the midrib breaking it into a number of leaflets, the leaf is called compound.

A bud is present in the axil of petiole in both simple and compound leaves, but not in the axil of leaflets of the compound leaf.

The compound leaves may be of two types –

  1. Pinnately compound leaf – a number of leaflets are present on a common axis, the rachis, which represents the midrib of the leaf. e.g., neem.
  2. Palmately compound leaves – the leaflets are attached at a common point, i.e., at the tip of petiole. e.g., Silk cotton.

1.jpg

Phyllotaxy:

Phyllotaxy is the pattern of arrangement of leaves on the stem or branch.

This is usually of three types –

  1. Alternate type – a single leaf arises at each node in alternate manner.

e.g., China rose, Mustard and Sun flower.

  1. Opposite type – a pair of leaves arise at each node and lie opposite to each other.

e.g., Calotropis and Guava.

  1. Whorled type If more than two leaves arise at a node and form a whorl.

e.g., Alstonia.

1.jpg

 Modifications of Leaves

  1. For support converted into tendrils for climbing. e.g., peas.
  2. For defense converted into spines. e.g., cactus.
  3. For food storage The fleshy leaves of onion and garlic.
  4. For photosynthesis (phyllode) – In some plants the leaves are small and short-lived. The petioles in these plants expand, become green and synthesise food. e.g., Australian acacia.
  5. For insectivory pitcher plant, venus-fly trap.

THE INFLORESCENCE

  • A flower is a modified shoot wherein the shoot apical meristem changes to floral meristem. Internodes do not elongate and the axis gets condensed.
  • The apex produces different kinds of floral appendages laterally at successive nodes instead of leaves. When a shoot tip transforms into a flower, it is always solitary.
  • The arrangement of flowers on the floral axis is termed as inflorescence.
  • Depending on whether the apex gets converted into a flower or continues to grow, two major types of inflorescences are defined –
  1. Racemose inflorescence – the main axis continues to grow, the flowers are borne laterally in an acropetal succession
  2. Cymose inflorescence – the main axis terminates in a flower, hence is limited in growth. The flowers are borne in a basipetal order

1.jpg

 THE FLOWER

  • The flower is the reproductive unit in the angiosperms. It is meant for sexual reproduction.
  • A typical flower has four different kinds of whorls arranged successively on the swollen end of the stalk or pedicel, called thalamus or receptacle.

These are calyx, corolla, androecium and gynoecium.

Calyx and corolla are accessory organs, while androecium and gynoecium are reproductive organs.

  • Perianth : In some flowers like lily, the calyx and corolla are not distinct and are termed as perianth.

Parts of a Flower

Each flower normally has four floral whorls, viz., calyx, corolla, androecium and gynoecium.

  1. Calyx (Sepals) –
    • The calyx may be gamosepalous (sepals united) or polysepalous (sepals free).
    • Generally, sepals are green, leaf like and protect the flower in the bud stage.
    • outermost whorl of the flower.
  2. Corolla (Petals) –

    • Petals are usually brightly coloured to attract insects for pollination.
    • corolla may be also free (gamopetalous) or united (polypetalous).
    • The shape and colour of corolla vary greatly in plants. Corolla may be tubular, bell-shaped, funnel-shaped or wheel-shaped.
  3. Androecium (Stamens) –
    • Represents the male reproductive organ.
    • Each stamen consists of a stalk or a filament and an anther.
    • Each anther is usually bilobed and each lobe has two chambers, the pollen-sacs.
    • The pollen grains are produced in pollen-sacs.
    • A sterile stamen is called staminode.
    • When stamens are attached to the petals, they are called epipetalous.             e.g., brinjal.
    • When stamens are attached to the perianth, they are called epiphyllous.       e.g., lily.
    • Fusion of stamen –
      • If the stamens in a flower remain free – Polyandrous.
      • If the stamens are united into one bundle – monoadelphous. e.g., china rose.
      • If the stamens are united into two bundles – diadelphous. e.g., pea.
      • If the stamens are united into more than two bundles – Polyadelphous. e.g., citrus.
    • There may be a variation in the length of filaments within a flower, as in Salvia and mustard.
  4. Gynoecium (Carpels/Pistils) –
    • Gynoecium is the female reproductive part of the flower.
    • A carpel consists of three parts – stigma, style and ovary.
      • Ovary is the enlarged basal part, on which lies the elongated tube, the style.
      • The style connects the ovary to the stigma.
      • The stigma is usually at the tip of the style and is the receptive surface for pollen grains.
    • Each ovary bears one or more ovules attached to a flattened, cushion-like placenta.
    • Types of gynoecium –
      • Monocarpellary – when only one carpel is present.
      • Multicarpellary – When more than one carpel is present.
      • Apocarpous – if carpels are free. e.g., lotus and rose.
      • Syncarpous – when carpels are fused. e.g., mustard and tomato.
    • After fertilisation, the ovules develop into seeds and the ovary matures into a fruit.

Aestivation

The mode of arrangement of sepals or petals in floral bud with respect to the other members of the same whorl is known as aestivation.

  1. Valvate When sepals or petals in a whorl just touch one another at the margin, without overlapping. e.g., Calotropis.
  2. Twisted If one margin of the appendage overlaps that of the next one and so on. e.g., china rose, lady’s finger and cotton.
  3. Imbricate If the margins of sepals or petals overlap one another but not in any particular direction. e.g., Cassia and gulmohur.
  4. Vaxillary (papilionaceous) – it’s special type of aestivation. It has five petals, the largest (standard) overlaps the two lateral petals (wings) which in turn overlap the two smallest anterior petals (keel). e.g., Pea, Bean.

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Placentation

The arrangement of ovules within the ovary is known as placentation.

  1. Marginal The placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge forming two rows. e.g., pea.
  2. Axile When the placenta is axial and the ovules are attached to it in a multilocular ovary. e.g., china rose, tomato and lemon.
  3. Parietal the ovules develop on the inner wall of the ovary or on peripheral part. Ovary is one-chambered but it becomes two chambered due to the formation of the false septum(Replum) e.g., mustard and Argemone.
  4. Basal the placenta develops at the base of ovary and a single ovule is attached to it. e.g., sunflower, marigold.
  5. Free Central When the ovules are borne on central axis and septa are absent. e.g., Dianthus, Primrose.

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 Types of flower

  1. Reproductive organs –
    • Unisexual when either only stamens or only carpels is present.
    • Bisexual When both androecium and gynoecium are present.
  2. Symmetry –
    • actinomorphic (radial symmetry) – When a flower can be divided into two equal radial halves in any radial plane passing through the centre. e.g., mustard, datura, chilli.
    • zygomorphic (bilateral symmetry) – When a flower can be divided into two similar halves only in one particular vertical plane. e.g., pea, gulmohur, bean, Cassia.
    • asymmetric (irregular) – if a flower cannot be divided into two similar halves by any vertical plane passing through the centre. e.g., canna.
  3. A flower may be trimerous, tetramerous or pentamerous when the floral appendages are in multiple of 3, 4 or 5, respectively.
  4. Bracts
    • Bracteate – Flowers with bracts (reduced leaf found at the base of the pedicel) are called bracteates.
    • Ebracteate – Flowers without bracts are called ebracteate.
  5. Based on the position of calyx, corolla and androecium in respect of the ovary on thalamus –
    • Hypogynous – the gynoecium occupies the highest position while the other parts are situated below it. The ovary in such flowers is said to be superior. e.g., mustard, china rose and brinjal.
    • Perigynous – If gynoecium is situated in the centre and other parts of the flower are located on the rim of the thalamus almost at the same level, it is called perigynous. The ovary here is said to be half inferior. e.g., plum, rose, peach.
    • Epigynous – the margin of thalamus grows upward enclosing the ovary completely and getting fused with it, the other parts of flower arise above the ovary. Hence, the ovary is said to be inferior. e.g., guava and cucumber, and the ray florets of sunflower.

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THE FRUIT

  • The fruit is a characteristic feature of the flowering(Angiospermic) plants.
  • It is a mature or ripened ovary, developed after fertilisation.
  • If a fruit is formed without fertilisation of the ovary, it is called a parthenocarpic fruit.
  • Generally, the fruit consists of a wall or pericarp and seeds.
  • The pericarp may be dry or fleshy.
  • When pericarp is thick and fleshy, it is differentiated into the outer epicarp, the middle mesocarp and the inner endocarp.
  • Drupe Fruit – In mango and coconut.

They develop from monocarpellary superior ovaries and are one seeded.

In mango the pericarp is well differentiated into an outer thin epicarp, a middle fleshy edible mesocarp and an inner stony hard endocarp.

In coconut the mesocarp is fibrous.

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 THE SEED

  • The ovules after fertilisation, develop into seeds.
  • A seed is made up of a seed coat and an embryo.
  • The embryo is made up of a radicle, an embryonal axis and one (wheat, maize) or two cotyledons (gram and pea).

Structure of a Dicotyledonous Seed

  • Seed coat – The outermost covering of a seed.

The seed coat has two layers, the outer testa and the inner tegmen.

  • Hilum – The hilum is a scar on the seed coat through which the developing seeds were attached to the fruit.
  • Micropyle – it is a small pore present above the hilum.
  • Embryo – it consists of an embryonal axis and two cotyledons.
  • Cotyledons – These are often fleshy and full of reserve food materials.
  • Radicle and plumule – they are present at the two ends of the embryonal axis.
  • Endosperm In some seeds such as castor the endosperm formed as a result of double fertilisation, is a food storing tissue. In plants such as bean, gram and pea, the endosperm is not present in mature seeds and such seeds are called nonendospermous.

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Structure of Monocotyledonous Seed

  • Seed Coat – In the seeds of cereals such as maize the seed coat is membranous and generally fused with the fruit wall, called Hull.
  • Endosperm – The endosperm is bulky and stores food. Generally, monocotyledonous seeds are endospermic but some as in orchids are non-endospermic.
  • Aleuron layer – The outer covering of endosperm separates the embryo by a proteinous layer called aleurone layer.
  • Embryo – The embryo is small and situated in a groove at one end of the endosperm.
  • Scutellum – one large and shield shaped cotyledon known as scutellum
  • Embryonal axis – ends are known as plumule and radicle.
  • Coleoptile and coleorhiza – The plumule and radicle are enclosed in sheaths which are called coleoptile and coleorhiza respectively.

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SEMI-TECHNICAL DESCRIPTION OF A TYPICAL FLOWERING PLANT

Symbols used in Floral Formula –

Plant Part                                                              Symbol/Abbreviation

Bracteate                                                                               Br

Ebracteate                                                                             Ebr

Bracteolate                                                                           Brl

Actinomorphic                                                                    ⊕

Zygomorphic                                                                        % or 1

Bisexual (Hermaphrodite)                                               1.jpg

Staminate                                                                              ♂

Pistillate                                                                                 ♀

Calyx, Sepals free                                                                Knumber

Calyx, Sepals united                                                            K(number)

Corolla, Petals free                                                              Cnumber

Corolla, Petals united                                                         C(number)

Androecium, stamens free                                                Anumber

Androecium monodelphous                                              A(number)

Gynoecium, carpels free                                                    Gnumber

Gynoecium, carpels united                                                G(number)

Ovary superior (Hypogunous flower)                              G

Ovary Inferior (Epigynous flower)                                      G‾

Ovary Half–inferior (Perigynous flower)                         G –

Epiphyllus  1.jpg

Epipetalous1.jpg

Floral formula also shows cohesion and adhesion within parts of whorls and in between whorls.  Brassicaceae).

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DESCRIPTION OF SOME IMPORTANT FAMILIES

Fabaceae

  • This family was earlier called Papilonoideae, a subfamily of family Leguminosae.
  • Habitat – It is distributed all over the world
  • Vegetative Characters –
    • Trees, shrubs, herbs;
    • root with root nodules;
    • Stem: erect or climber;
    • Leaves: alternate, pinnately compound or simple; leaf base, pulvinate; stipulate; venation reticulate.
  • Floral characters –
    • Inflorescence: racemose
    • Flower: bisexual, zygomorphic
    • Calyx: sepals five, gamosepalous; imbricate aestivation
    • Corolla: petals five, polypetalous, papilionaceous, consisting of a posterior standard, two lateral wings, two anterior ones forming a keel (enclosing stamens and pistil), vexillary aestivation
    • Androecium: ten, diadelphous, anther dithecous
    • Gynoecium: ovary superior, mono carpellary, unilocular with many ovules, style single
  • Fruit – legume
  • Seed – one to many, non-endospermic.
  • Floral Formula – 1.jpg
  • Economic importance –
    • pulses (gram, arhar, sem, moong, soyabean)
    • edible oil (soyabean, groundnut)
    • dye (indigofera)
    • fibres (sunhemp)
    • fodder (Sesbania, Trifolium),
    • ornamentals (lupin, sweet pea);
    • medicine (muliathi).

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Solanaceae

  • It is a large family, commonly called as the ‘potato family’.
  • Habitat – It is widely distributed in tropics, subtropics and even temperate zones.
  • Vegetative Characters –
    • Plants mostly, herbs, shrubs and small trees
    • Stem: herbaceous rarely woody, aerial; erect, cylindrical, branched, solid or hollow, hairy or glabrous, underground stem in potato (Solanum tuberosum)
    • Leaves: alternate, simple, rarely pinnately compound, exstipulate; venation reticulate
  • Floral Characters –
    • Inflorescence: Solitary, axillary or cymose as in Solanum
    • Flower: bisexual, actinomorphic
    • Calyx: sepals five, united, persistent, valvate aestivation
    • Corolla: petals five, united; valvate aestivation
    • Androecium: stamens five, epipetalous
    • Gynoecium: bicarpellary, syncarpous; ovary superior, bilocular, placenta swollen with many ovules
  • Fruits – berry or capsule
  • Seeds – many, endospermous
  • Floral Formula – 1.jpg
  • Economic Importance –
    • source of food (tomato, brinjal, potato),
    • spice (chilli);
    • medicine (belladonna, ashwagandha);
    • fumigatory (tobacco);
    • ornamentals (petunia).

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Lilaceae

  • Commonly called the ‘Lily family’.
  • It is a characteristic representative of monocotyledonous plants.
  • Habitat – It is distributed world wide.
  • Vegetative characters –
    • Perennial herbs with underground bulbs/corms/ Rhizomes
    • Leaves mostly basal, alternate, linear, exstipulate with parallel venation
  • Floral characters –
    • Inflorescence: solitary / cymose; often umbellate clusters
    • Flower: bisexual; actinomorphic
    • Perianth: tepal six (3+3), often united into tube; valvate aestivation
    • Androcium: stamen six, (3+3)
    • Gynoecium: tricarpellary, syncarpous, ovary superior, trilocular with many ovules; axile placentation
  • Fruit – capsule, rarely berry
  • Seed – endospermous
  • Floral Formula – 1.jpg
  • Economic Importance –
    • ornamentals (tulip, Gloriosa),
    • medicine (Aloe),
    • vegetables (Asparagus)
    • colchicine (Colchicum autumnale).

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CHAPTER 5 – MORPHOLOGY OF FLOWERING PLANTS

CHAPTER 4 – ANIMAL KINGDOM

BASIS OF CLASSIFICATION –

Levels of Organisation

  1. Cellular level – cells are arranged as loose cell aggregates. Some division of labour (activities) occur among the cells. e.g., Sponges.
  2. Tissue level – the cells performing the same function are arranged into tissues. e.g., coelenterates.
  3. Organ level – tissues are grouped together to form organs, each specialized for a particular function. e.g., Platyhelminthes, ascheminthes.
  4. Organ system level – organs are associated to form functional systems, each system concerned with a specific physiological function. e.g., Annelids, Arthropods, Molluscs, Echinoderms and Chordates.

Symmetry

  1. Asymmetrical – any plane that passes through the centre does not divide body into equal halves. e.g., Sponges.
  2. Radial symmetry – When any plane passing through the central axis of the body divides the organism into two identical halves. e.g., Coelenterates, ctenophores and echinoderms (adults only).
  3. bilateral symmetry – the body can be divided into identical left and right halves in only one plane. e.g., Annelids, Arthropods, Molluscs, Echinoderms (larvae) and Chordates.

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 germ layers

  1. Diploblastic – Animals in which the cells are arranged in two embryonic layers, an external ectoderm and an internal endoderm. An undifferentiated layer, mesoglea, is present in between the ectoderm and the endoderm. e.g., Sponges, coelenterates.
  2. Triploblastic – Animals in which the cells are arranged in three embryonic layers, an external ectoderm, an internal endoderm and middle mesoderm. e.g., Platyhelminthes, ascheminthes, Annelids, Arthropods, Molluscs, Echinoderms and Chordates.

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 Coelom

The body cavity, which is lined by mesoderm on both sides is called coelom.

  1. Acoelomates – animals in which the body cavity is absent. e.g., Sponges, coelenterates, platyhelminthes.
  2. Pseudocoelomates – In some animals, the body cavity is not lined by mesoderm, instead, the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called pseudocoelom and the animals possessing them are called pseudocoelomates, g., aschelminthes
  3. Coelomates – Animals possessing coelom are called coelomates, g., annelids, molluscs, arthropods, echinoderms, hemichordates and chordates.

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 Segmentation

In some animals, the body is externally and internally divided into segments with a serial repetition of at least some organs. The body shows this pattern called metameric segmentation and the phenomenon is known as metamerism. e.g., in earthworm.

Notochord

Notochord is a mesodermally derived rod-like structure formed on the dorsal side during embryonic development in some animals.

  1. Chordates – Animals with notochord in any stage of life. e.g., Fishes, Amphibians, Reptiles, Birds, Mammals etc.
  2. Nonchordates – Those animals which do not form this structure are called non-chordates, e.g., Porifera to echinoderms.

 Digestive system

  1. Incomplete digestive system – digestive system has only a single opening to the outside of the body that serves as both mouth and anus. e.g., Coelenterates, Platyhelminthes
  2. Complete digestive system – digestive system has two openings, mouth and anus. e.g., aschelminthes to chordates.

Circulatory system

  1. open type – Blood is pumped out of the heart and the cells and tissues are directly bathed in it or
  2. closed type in which the blood is circulated through a series of vessels of varying diameters (arteries, veins and capillaries).

 

CLASSIFICATION OF ANIMALS

 

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Phylum – Porifera (Sponges)

  • Habitat – Aquatic – generally marine, some are fresh water.
  • Symmetry – mostly asymmetric.
  • Organization level – multicellular with cellular level of organisation.
  • Canal system – Sponges have a water transport or canal system. Water enters through minute pores (ostia) in the body wall into a central cavity, spongocoel, from where it goes out through the osculum.

This pathway of water transport is helpful in food gathering, respiratory exchange and removal of waste.

  • Special cells – Choanocytes or collar cells line the spongocoel and the canals. These cells are flagellated.
  • Digestion – Intracellular.
  • Skeleton – Made up of spicules or sponging fibres.
  • Reproduction –    Bisexual or hermaphrodite animals.

Sponges reproduce asexually (fragmentation) and sexually.

  • Fertilisation – Internal
  • Development – Indirect having a larval stage which is morphologically distinct from the adult.
  • Examples: Sycon (Scypha), Spongilla (Fresh water sponge) and Euspongia (Bath sponge).

 

Phylum – Coelenterata (Cnidaria)

  • Habitat – Aquatic, mostly marine, sessile or free-swimming,
  • Symmetry – Radially symmetrical.
  • Special cells – cnidoblasts or cnidocytes (which contain the stinging capsules or nematocytes) present on the tentacles and the body.

Cnidoblasts are used for anchorage, defense and for the capture of prey.

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  • Level of organization – tissue level of organisation and diploblastic.
  • Body Cavity – Absent, central gastro-vascular cavity present with a single opening, hypostome.
  • Digestion – both extracellular and intracellular.
  • Skeleton – Some of the cnidarians – corals have a skeleton composed of calcium carbonate.
  • Basic body forms Cnidarians exhibit two basic body forms called polyp and medusa.

Polyp – It is a sessile and cylindrical form like Hydra, Adamsia, etc.

Medusa – it is umbrella-shaped and free-swimming like Aurelia or jelly fish.

  • Alternation of generation (Metagenesis) – some cniderians exist in both polyp and medusa forms and exhibit alternation of generation (Metagenesis), i.e., polyps produce medusae asexually and medusae form the polyps sexually (e.g., Obelia).1.jpg
  • Examples: Hydra, Aurelia (Jelly fish), Obelia (Sea Fur), Physalia (Portuguese man-of-war), Adamsia (Sea anemone), Pennatula (Sea-pen), Gorgonia (Sea-fan) and Meandrina (Brain coral).

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Phylum – Ctenophora (Sea walnuts or Comb jellies)

  • Habitat – Exclusively marine.
  • Symmetry – radially symmetrical.
  • Level of organization – tissue level of organization and diploblastic.
  • Special organ – eight external rows of ciliated comb plates, which help in locomotion.
  • Digestion – both extracellular and intracellular.
  • Special property – Bioluminescence (the property of a living organism to emit light).
  • Reproduction – Bisexual animals (Hermaphrodites).

                              Only sexual reproduction.

  • Fertilisation – external.
  • Development – indirect development.
  • Examples: Pleurobrachia and Ctenoplana.

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Phylum – Platyhelminthes

  • Body shape – They have dorso-ventrally flattened body, hence are called flatworms.
  • Habitat – Mostly endoparasites found in animals.
  • Symmetry – bilaterally symmetrical.
  • Body organization – organ level of organisation and triploblastic.
  • Body cavity – Absent, acoelomates.
  • Special structures – Hooks and suckers are present in the parasitic forms for support and absorption. Some of them absorb nutrients from the host directly through their body surface.
  • Excretory cells – flame cells help in osmoregulation and excretion.
  • Reproduction – Bisexual animals (Hermaphrodites).
  • Fertilisation – Internal.
  • Development – Indirect through many larval stages.
  • Some members like Planaria possess high regeneration capacity.
  • Examples: Taenia (Tapeworm), Fasciola (Liver fluke), Planaria.

 Phylum – Aschelminthes

  • Body shape – Circular in cross-section, hence, the name roundworms.
  • Habitat – They may be free living, aquatic and terrestrial or parasitic in plants and animals.
  • Level of organization – organ-system level of body organization and triploblastic.
  • Symmetry – bilaterally symmetrical.
  • Body Cavity – Pseudocoelomate animals.
  • Digestive system – Alimentary canal is complete with a well developed muscular pharynx.
  • Excretion – An excretory tube removes body wastes from the body cavity through the excretory pore.
  • Reproduction – unisexual or dioecious. Also show sexual dimorphism (females are longer than males)
  • Fertilisation – internal.
  • Development – direct (the young ones resemble the adult) or indirect (larvae is present).
  • Examples: Ascaris (Round Worm), Wuchereria (Filaria worm), Ancylostoma (Hookworm).

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Phylum – Annelida

  • Their body surface is distinctly marked out into segments or metameres (Latin, annulus : little ring) and, hence, the phylum name Annelida.
  • Habitat – aquatic (marine and fresh water) or terrestrial; free-living, and sometimes parasitic.
  • Level of organization – organ-system level and triploblastic animals.
  • Symmetry – bilateral symmetry.
  • Body cavity – present and coelomates.
  • Locomotory organ – Body wall which has longitudinal and circular muscles. Aquatic annelids like Nereis possess lateral appendages, parapodia (for swimming).
  • Circulatory system – closed circulatory system.
  • Excretory organ – Nephridia which help in osmoregulation and excretion.
  • Nervous system – consists of paired ganglia connected by lateral nerves to a double ventral nerve cord.
  • Reproduction – some are unisexual or dioecious (Nereis) and some are bisexual or monoecious (earthworms and leeches). Reproduces sexually.
  • Examples: Nereis, Pheretima (Earthworm) and Hirudinaria (Blood sucking leech).

Phylum – Arthropoda

  • This is the largest phylum of Animalia which includes insects.
  • Level of organization – organ-system level of organisation.
  • Symmetry, body cavity – bilaterally symmetrical, triploblastic, segmented and coelomate animals.
  • Skeleton – exoskeleton made up of chitin.
  • Body division – The body consists of head, thorax and abdomen.
  • Locomotion – by jointed appendages (arthros-joint, poda-appendages), hence name arthropoda.
  • Respiration – by gills, book gills, book lungs or tracheal system.
  • Circulatory system – open type.
  • Sensory organs – antennae, eyes (compound and simple), statocysts or balance organs are present.
  • Excretion – through malpighian tubules.
  • Reproduction – mostly dioecious animals.
  • Fertilisation – usually internal. They are mostly oviparous.
  • Development – direct or indirect.
  • Examples:

Economically important insects    –    Apis (Honey bee), Bombyx (Silkworm), Laccifer (Lac insect)

Vectors                                     –    Anopheles, Culex and Aedes (Mosquitoes)

Gregarious pest                          –    Locusta (Locust)

Living fossil                              –    Limulus (King crab).

Phylum – Mollusca

  • This is the second largest animal phylum.
  • Habitat – terrestrial or aquatic (marine or fresh water).
  • Symmetry, coelom – bilaterally symmetrical, triploblastic and coelomate animals.
  • Body division – Body is covered by a calcareous shell and is unsegmented with a distinct head, muscular foot and visceral hump.
  • Special structure – A soft and spongy layer of skin forms a mantle over the visceral hump.
  • Respiration and excretion – The space between the hump and the mantle is called the mantle cavity in which feather like gills are present. They have respiratory and excretory functions.
  • Sense organs – The anterior head region has sensory tentacles.
  • Feeding organ – The mouth contains a file-like rasping organ for feeding, called radula.
  • Reproduction and development – usually dioecious and oviparous with indirect development.
  • Examples: Pila (Apple snail), Pinctada (Pearl oyster), Sepia (Cuttlefish), Loligo (Squid), Octopus (Devil fish), Aplysia (Seahare), Dentalium (Tusk shell) and Chaetopleura (Chiton).

 

Phylum – Echinodermata

  • These animals have an endoskeleton of calcareous ossicles and, hence, the name Echinodermata (Spiny bodied).
  • Habitat – All are marine.
  • Symmetry – The adult echinoderms are radially symmetrical but larvae are bilaterally symmetrical.
  • Digestive system – complete with mouth on the lower (ventral) side and anus on the upper (dorsal) side.
  • Water vascular system – distinctive feature. Helps in locomotion, capture and transport of food and respiration.
  • Excretory system – absent.
  • Reproduction – Dioecious animals ,  Reproduction is sexual.
  • Fertilisation – usually external.
  • Development – indirect with free-swimming larva.
  • Examples: Asterias (Star fish), Echinus (Sea urchin), Antedon (Sea lily), Cucumaria (Sea cucumber) and Ophiura (Brittle star).

 

Phylum – Hemichordata

  • Earlier considered as a sub-phylum under phylum Chordata, but now it is placed as a separate phylum under non-chordata.
  • Habitat – consists of a small group of worm-like marine animals.
  • Level of organization, symmetry, body cavity – organ-system level of organization, bilaterally symmetrical, triploblastic and coelomate animals.
  • Body shape and division – The body is cylindrical and is composed of an anterior proboscis, a collar and a long trunk.
  • Circulatory system – Open type.
  • Respiration – through gills.
  • Excretory organ – proboscis gland.
  • Reproduction, fertilisation, development – Diocious animals, external Fertilisation, indirect Development.
  • Examples: Balanoglossus and Saccoglossus.

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Phylum – Chordata

  • Characteristic features –

a notochord,

a dorsal hollow nerve cord

paired pharyngeal gill slits

post anal tail

closed circulatory system

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  • Symmetry, body cavity, level of organization – These are bilaterally symmetrical, triploblastic, coelomate with organ-system level of organisation.
  • Phylum Chordata is divided into three subphyla : Urochordata or Tunicata, Cephalochordata and Vertebrata.
  • Subphyla Urochordata and Cephalochordata are often referred to as protochordates.

 

Subphylum – Urochordata

  • Exclusively marine.
  • notochord is present only in larval tail,
  • Examples: Ascidia, Salpa ,Doliolum.

 

Subphylum – Cephalochordata

  • Notochord extends from head to tail region and is persistent throughout their life.
  • Example: Branchiostoma (Amphioxus or Lancelet).

Subphylum – Vertebrata

  • Possess notochord during the embryonic period.
  • The notochord is replaced by a cartilaginous or bony vertebral column in the adult.
  • Thus all vertebrates are chordates but all chordates are not vertebrates.
  • Vertebrates have a ventral muscular heart with two, three or four chambers, kidneys for excretion and osmoregulation and paired appendages which may be fins or limbs.

 

TABLE: Comparison of Chordates and Non- chordates
Chordates Non-chordates
Notochord present Notochord absent
Central nervous system is dorsal Central nervous system is ventral, solid, hollow and single. and double
Pharynx perforated by gill slits Gill slits are absent
Heart is ventral Heart is dorsal (if present).
A post-anal part (tail) is present. Post-anal tail is absent.

 

  Classification of Vertebrata –

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Class – Cyclostomata

  • Habitat – ectoparasites on some fishes. Body shape – elongated body
  • Respiration – 6-15 pairs of gill slits.
  • Mouth – Cyclostomes have a sucking and circular mouth without jaws.
  • Scales and paired fins are absent.
  • Cranium and vertebral column are cartilaginous.
  • Circulation is of closed type.
  • Marine but migrate to fresh water for spawning. After spawning, within a few days, they die. Their larvae, after metamorphosis, return to the ocean.
  • Examples: Petromyzon (Lamprey) and Myxine (Hagfish).

 

Class – Chondricthyes

  • marine animals.
  • Their body is streamlined and they have cartilaginous endoskeleton.
  • Mouth is located ventrally.
  • Notochord is persistent throughout life.
  • Gill slits are separate and without operculum (gill cover).
  • The skin is tough, containing minute placoid scales.
  • Teeth are modified placoid scales which are backwardly directed.
  • Their jaws are very powerful. These animals are predaceous.
  • Due to the absence of air bladder, they have to swim constantly to avoid sinking.
  • Heart is two-chambered (one auricle and one ventricle).
  • Some of them have electric organs (e.g., Torpedo) and some possess poison sting (e.g., Trygon).
  • They are cold-blooded (poikilothermous) animals, i.e., they lack the capacity to regulate their body temperature.
  • Sexes are separate. In males pelvic fins bear claspers. They have internal fertilisation and many of them are viviparous.
  • Examples: Scoliodon (Dog fish), Pristis (Saw fish), Carcharodon (Great white shark), Trygon (Sting ray), Torpedo (electric ray).

 

Class – Osteichtyes

  • Both marine and fresh water fishes
  • Their body is streamlined and they have bony endoskeleton skeleton.
  • Mouth is mostly terminal.
  • They have four pairs of gills which are covered by an operculum on each side.
  • Skin is covered with cycloid/ctenoid scales.
  • Air bladder is present which regulates buoyancy.
  • Heart is two chambered (one auricle and one ventricle).
  • They are cold-blooded animals.
  • Sexes are separate. Fertilisation is usually external. They are mostly oviparous and development is direct.
  • Examples:

Marine              –    Exocoetus (Flying fish), Hippocampus (Sea horse);

Freshwater         –    Labeo (Rohu), Catla (Katla), Clarias (Magur);

Aquarium          –    Betta (Fighting fish), Pterophyllum (Angel fish).

Class – Amphibia

  • amphibians can live in aquatic as well as terrestrial habitats.
  • Most of them have two pairs of limbs.
  • Body is divisible into head and trunk. Tail may be present in some.
  • The amphibian skin is moist (without scales).
  • The eyes have eyelids.
  • A tympanum represents the ear.
  • Alimentary canal, urinary and reproductive tracts open into a common chamber called cloaca which opens to the exterior.
  • Respiration is by gills, lungs and through skin.
  • The heart is three chambered (two auricles and one ventricle).
  • These are cold-blooded animals.
  • Sexes are separate. Fertilisation is external. They are oviparous and development is direct or indirect.
  • Examples: Bufo (Toad), Rana (Frog), Hyla (Tree frog), Salamandra (Salamander), Ichthyophis (Limbless amphibia).

 

Class – Reptilia

  • Locomotion is creeping or crawling.
  • mostly terrestrial animals.
  • body is covered by dry and cornified skin, epidermal scales or scutes
  • They do not have external ear openings. Tympanum represents ear.
  • Limbs, when present, are two pairs.
  • Heart is usually three-chambered, but four-chambered in crocodiles.
  • Reptiles are poikilotherms.
  • Snakes and lizards shed their scales as skin cast.
  • Sexes are separate. Fertilisation is internal. They are oviparous and development is direct.
  • Examples: Chelone (Turtle), Testudo (Tortoise), Chameleon (Tree lizard), Calotes (Garden lizard), Crocodilus (Crocodile), Alligator (Alligator). Hemidactylus (Wall lizard), Poisonous snakes – Naja (Cobra), Bangarus (Krait), Vipera (Viper).

 

Class – Aves

  • The characteristic features are the presence of feathers and most of them can fly except flightless birds (e.g., Ostrich).
  • They possess beak.
  • The forelimbs are modified into wings.
  • The hind limbs generally have scales and are modified for walking, swimming or clasping the tree branches.
  • Skin is dry without glands except the oil gland at the base of the tail.
  • Endoskeleton is fully ossified (bony) and the long bones are hollow with air cavities (pneumatic).
  • The digestive tract of birds has additional chambers, the crop and gizzard.
  • Heart is completely four chambered.
  • They are warm-blooded (homoiothermous) animals, i.e., they are able to maintain a constant body temperature.
  • Respiration is by lungs. Air sacs connected to lungs supplement respiration.
  • Sexes are separate. Fertilisation is internal. They are oviparous and development is direct.
  • Examples : Corvus (Crow), Columba (Pigeon), Psittacula (Parrot), Struthio (Ostrich), Pavo (Peacock), Aptenodytes (Penguin), Neophron (Vulture).

 

Class – Mammalia

  • They are found in a variety of habitats – polarice caps, deserts, mountains, forests, grasslands and dark caves.
  • Some of them have adapted to fly or live in water.
  • The most unique mammalian characteristic is the presence of milk producing glands (mammary glands) by which the young ones are nourished.
  • They have two pairs of limbs, adapted for walking, running, climbing, burrowing, swimming or flying.
  • The skin of mammals is unique in possessing hair.
  • External ears or pinnae are present.
  • Different types of teeth are present in the jaw.
  • Heart is four chambered.
  • They are homoiothermous.
  • Respiration is by lungs.
  • Sexes are separate and fertilisation is internal.
  • They are viviparous with few exceptions and development is direct.
  • Examples:

OviparousOrnithorhynchus (Platypus);

Viviparous Macropus (Kangaroo), Pteropus (Flying fox), Camelus (Camel), Macaca (Monkey), Rattus (Rat), Canis (Dog), Felis (Cat), Elephas (Elephant), Equus (Horse), Delphinus (Common dolphin), Balaenoptera (Blue whale), Panthera tigris (Tiger), Panthera leo (Lion).

 

Table : Salient features of different phyla of Animal kingdom

Phylum Level of Organi­sation Symme­try Coelom Segmen­tation Digestive System Circulatory System Respiratory System Distinctive Features
Porifera Cellular Many Absent Absent Absent Absent Absent Body with pores and Canals In walls.
Coelenterata (Cnidaria) Tissue Radial Absent Absent Incomplete Absent Absent Cnidoblasts present
Ctenophora Tissue Radial Absent Absent Incomplete Absent Absent Comb plates for locomotion.
Platyhelminthes Organ &

Organ-system

Bilateral Absent Absent Incomplete Absent Absent Flat body, suckers.
Aschelminthes Organ- system Bilateral Pseudo

coelomate

Absent Complete Absent Absent Often worm shaped,

elongated.

Annelida Organ- system Bilateral Coelomate Present Complete Present Present Body segment ation like rings.
Arthropoda Organ- system Bilateral Coelomate Present Complete Present Present Exoskeleton of cu­ticle, jointed ap­pendages.
Mollusca Organ- system Bilateral Coelomate Absent Complete Present Present External skeleton shell usually present.
Echinodermata Organ- system Radial Coelomate Absent Complete Present Present Water vascular system, radial symmetry.
Heml-chordata Organ- system Bilateral Coelornate Absent Complete Present Present Worm-like with proboscis, collar and trunk.
Chordata Organ- system Bilateral Coelomate Present Complete Present Present Notochord, dorsal hollow nerve cord, gill slits with limbs or fins.

 

PRINTABLE PDF FILE IS GIVEN IN LINK BELOW –

CHAPTER 4 – ANIMAL KINGDOM

CHAPTER 3 – PLANT KINGDOM

 

Systems of classification –

Artificial System of classification –

  • It was the earliest systems of classification.
  • It used only gross superficial morphological characters such as habit, colour, number and shape of leaves, etc.
  • They were based mainly on vegetative characters or on the androecium structure (system given by Linnaeus).
  • They separated the closely related species since they were based on a few characteristics.
  • Also, the artificial systems gave equal weightage to vegetative and sexual characteristics; this is not acceptable since we know that often the vegetative characters are more easily affected by environment.

e.g., Linnaeus classification of plants based on no of androecium.

Natural system of classification –

  • It was based on natural affinities among the organisms and consider, not only the external features, but also internal features, like ultrastructure, anatomy, embryology and phytochemistry.

e.g., George Bentham and Joseph Dalton Hooker classification of flowering plants.

Phylogenetic classification systems –

  • It is most acceptable system.
  • It is based on evolutionary relationships between the various organisms.
  • This assumes that organisms belonging to the same taxa have a common ancestor.

New development in taxonomy –

  • Numerical Taxonomy –

    It is carried out using computers and is based on all observable characteristics. Number and codes are assigned to all the characters and the data are then processed. In this way each character is given equal importance and at the same time hundreds of characters can be considered.

  • Cytotaxonomy –

    It is based on cytological information like chromosome number, structure, behaviour.

  • Chemotaxonomy –

    It is based on the chemical constituents of the plant.

Plant Classification

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ALGAE / THALLOPHYTA

  • Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic (both fresh water and marine) organisms.
  • Some Algae also occur in association with fungi (lichen) and animals (e.g., on sloth bear).

Size and form of algae

  • The microscopic unicellular forms – Chlamydomonas,
  • Colonial forms – Volvox
  • Filamentous forms – Ulothrix and
  • Marine and massive plant bodies – kelps.

Reproduction in Algae

By vegetative, asexual and sexual methods.

  • Vegetative reproduction – by fragmentation, each fragment develops into a thallus.
  • Asexual reproduction – by the production of different types of spores like zoospores.They are flagellated (motile) and on germination gives rise to new plants.
  • Sexual reproduction – through fusion of two gametes.
    • Isogamous – If gametes are flagellated and similar in size – Chlamydomonas.
      If gametes are non-flagellated and similar in size – Spirogyra.
    • Anisogamous – If gametes are dissimilar in size. e.g., some species of Chlamydomonas. 
    • Oogamous – Fusion between one large, non-motile female gamete and a smaller, motile male gamete is termed oogamous, e.g., Volvox, Fucus.
  •  Economic importance of Algae
    • At least a half of the total carbon dioxide fixation on earth is carried out by algae through photosynthesis.
    • They are primary producers of energy-rich compounds which form the basis of the food cycles of all aquatic animals. Many species of Porphyra, Laminaria and Sargassum are used as food.
    • Certain marine brown and red algae produce large amounts of hydrocolloids (water holding substances), e.g., algin (brown algae) and carrageen (red algae).
    • Agar, one of the commercial products obtained from Gelidium and Gracilaria are used to grow microbes and in preparations of ice-creams and jellies.
    • Chlorella and Spirullina are unicellular algae, rich in proteins and are used as food supplements even by space travellers. (SCP – single cell protein)

The algae are divided into three main classes (on the basis of pigment and stored food): Chlorophyceae, Phaeophyceae and Rhodophyceae.

Chlorophyceae (Green algae)

  • The plant body may be unicellular, colonial or filamentous.
  • They are usually grass green due to the dominance of pigments chlorophyll a and b.
  • The chloroplasts may be discoid, plate-like, reticulate, cup-shaped, spiral or ribbon-shaped in different species.
  • Most of the members have one or more storage bodies called pyrenoids located in the chloroplasts.
  • Pyrenoids contain protein besides starch. Some algae may store food in the form of oil droplets.
  • Green algae usually have a rigid cell wall made of an inner layer of cellulose and an outer layer of pectose.
  • Vegetative reproduction – by fragmentation or by formation of different types of spores.
  • Asexual reproduction – by flagellated zoospores produced in zoosporangia.
  • The sexual reproduction – may be isogamous, anisogamous or oogamous.
  • e.g., Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara.

Phaeophyceae (Brown algae)

  • found primarily in marine habitats.
  • Present in from simple branched, filamentous forms (Ectocarpus) to profusely branched forms as represented by kelps.
  • They possess chlorophyll a, c, carotenoids and xanthophylls (fucoxanthin).
  • Food is stored as complex carbohydrates, which may be in the form of laminarin or mannitol.
  • Cell wall made-up of cellulose and has outer coating of gelatinous substance algin.
  • The plant body is usually attached to the substratum by a holdfast, and has a stalk – the stipe and leaf like photosynthetic organ – the frond.
  • Vegetative reproduction – by fragmentation.
  • Asexual reproduction – by biflagellate zoospores that are pear-shaped and have two unequal laterally attached flagella.
  • Sexual reproduction – may be isogamous, anisogamous or oogamous.
    • Union of gametes may take place in water or within the oogonium (oogamous species).
    • The gametes are pyriform (pear-shaped) and bear two laterally attached flagella.
  • e.g., Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus.

Rhodophyceae (Red algae)

  • Predominance of the red pigment, r-phycoerythrin.
  • Majority of the red algae are marine with greater concentrations found in the warmer areas.
  • They occur in both well-lighted regions close to the surface of water and also at great depths in oceans where relatively little light penetrates.
  • The red thalli of most of the red algae are multicellular.
  • The food is stored as floridean starch which is very similar to amylopectin and glycogen in structure.
  • Vegetative reproduction – by fragmentation.
  • Asexual reproduction – by non-motile spores.
  • Sexual reproduction – by non-motile gametes.
    • Sexual reproduction is oogamous.
  • e.g., Polysiphonia, Porphyra, Gracilaria and Gelidium.

 

 

TABLE : Divisions of Algae and their Main Characteristics

Classes Common Name Major Pigments Stored Food Cell Wall Flagellar Number and Position of Insertions Habitat
Chlorophyceae Green algae

 

Chlorophyll a, b Starch Cellulose 2-8, equal, apical Fresh water, brackish water,  salt water
Phaeophyceae Brown algae Chlorophyll a, c, fucoxanthin Mannitol, laminarin Cellulose and algin 2, unequal, lateral Fresh water (rare) brackish water, salt water
Rhodophyceae Red algae Chlorophyll a, d, phycoerythrin Floridean starch Cellulose Absent Fresh water (some), brackish water, salt water (most)

 

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BRYOPHYTES (Amphibians of the plant kingdom)

  • Bryophytes include the various mosses and liverworts that are found commonly growing in moist shaded areas in the hills.
  • Bryophytes are also called amphibians of the plant kingdom because these plants can live in soil but are dependent on water for sexual reproduction.
  • They play an important role in plant succession on bare rocks/soil.
  • Structure / Plant body –

The plant body of bryophytes is more differentiated than that of algae. It is thallus-like and prostrate or erect, and attached to the substratum by unicellular or multicellular rhizoids (root like structure).

They lack true roots, stem or leaves. They may possess root-like, leaf-like or stem-like structures.

The main plant body of the bryophyte is haploid. It produces gametes, hence is called a gametophyte.

  • Sex organs –

The sex organs in bryophytes are multicellular.

The male sex organ is called antheridium. They produce biflagellate antherozoids.

The female sex organ called archegonium is flask-shaped and produces a single egg.

  • Fertilization and development –

The antherozoids are released into water where they come in contact with archegonium.

An antherozoid fuses with the egg to produce the zygote.

Zygotes do not undergo reduction division immediately. They produce a multicellular body called a sporophyte.

The sporophyte is not free-living but attached to the photosynthetic gametophyte and derives nourishment from it. (sporophyte is parasite or dependent on gametophyte).

Some cells of the sporophyte undergo reduction division (meiosis) to produce haploid spores.

These spores germinate to produce gametophyte.

  • Economic importance –

    • some mosses provide food for herbaceous mammals, birds and other animals.
    • Species of Sphagnum, a moss, provide peat that have long been used as fuel, and because of their capacity to hold water as packing material for trans-shipment of living material.
    • Mosses along with lichens are the first organisms to colonise rocks and hence, are of great ecological importance.
    • They decompose rocks making the substrate suitable for the growth of higher plants.
    • Since mosses form dense mats on the soil, they reduce the impact of falling rain and prevent soil erosion.

The bryophytes are divided into liverworts and mosses.

Liverworts

  • The plant body of a liverwort is thalloid.
  • The thallus is dorsiventral and closely appressed to the substrate.
  • The leafy members have tiny leaf-like appendages in two rows on the stem-like structures.
  • Asexual reproduction – by fragmentation of thalli, or by the formation of specialised structures called gemmae.

Gemmae are green, multicellular, asexual buds, which develop in small receptacles called gemma cups located on the thalli.

The gemmae become detached from the parent body and germinate to form new individuals.

  • Sexual reproduction – male and female sex organs are produced either on the same or on different thalli.
  • The sporophyte is differentiated into a foot, seta and capsule.

After meiosis, spores are produced within the capsule.

These spores germinate to form free-living gametophytes.

e.g., Marchantia

Mosses

  • The predominant stage of the life cycle of a moss is the gametophyte which consists of two stages.

The first stage is the protonema stage, which develops directly from a spore. It is a creeping, green, branched and frequently filamentous stage.

The second stage is the leafy stage, which develops from the secondary protonema as a lateral bud. It has upright, slender axes bearing spirally arranged leaves. They are attached to the soil through multicellular and branched rhizoids. This stage bears the sex organs.

  • Vegetative reproduction – by fragmentation and budding in the secondary protonema.
  • sexual reproduction – by the sex organs antheridia and archegonia, which are produced at the apex of the leafy shoots.
  • After fertilization – the zygote develops into a sporophyte, consisting of a foot, seta and capsule. The sporophyte in mosses is more elaborate than that in liverworts. The capsule contains spores, which are formed after meiosis.
  • The mosses have an elaborate mechanism of spore dispersal.

e.g., Funaria, Polytrichum and Sphagnum.

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PTERIDOPHYTES

  • The Pteridophytes include horsetails and ferns.
  • Evolutionarily, they are the first terrestrial plants to possess vascular tissues – xylem and phloem.
  • The pteridophytes are found in cool, damp, shady places though some may flourish well in sandy-soil conditions.
  • Structure / Plant body –

    • The main plant body is a sporophyte which is differentiated into true root, stem and leaves.
    • These organs possess well-differentiated vascular tissues.
    • The leaves in pteridophyta are small (microphylls) – Selaginella or large (macrophylls) – ferns.
    • The sporophytes bear sporangia that are subtended by leaf-like appendages called sporophylls.
    • In some cases sporophylls may form distinct compact structures called strobili or cones (Selaginella, Equisetum).
  • Life cycle

    • The sporangia produce spores by meiosis in spore mother cells.
    • The spores germinate to give rise to inconspicuous, small but multicellular, free-living, mostly photosynthetic thalloid gametophytes called prothallus.
    • These gametophytes require cool, damp, shady places to grow. Because of this specific restricted requirement and the need for water for fertilisation, the spread of living pteridophytes is limited and restricted to narrow geographical regions.
  • Sexual Reproduction –

    • The gametophytes bear male and female sex organs called antheridia and archegonia, respectively.
    • Water is required for transfer of antherozoids (the male gametes) to the mouth of archegonium.
    • Fusion of male gamete with the egg present in the archegonium result in the formation of zygote.
  • Development of zygote –

    • Zygote thereafter produces a multicellular well-differentiated sporophyte which is the dominant phase of the pteridophytes.

 

There are two types of sporophytes in pteridophytes –

  • Homosporous – all spores are of similar kinds, e.g., In majority of the pteridophytes.
  • Heterosporous – 2 types of spores are produced, (a) small, male microspores, and (b) large, female megaspores. e.g., Selaginella and

The megaspores and microspores germinate and give rise to female and male gametophytes, respectively.

The female gametophytes in these plants are retained on the parent sporophytes for variable periods.

The development of the zygotes into young embryos takes place within the female gametophytes. This event is a precursor to the seed habit considered an important step in evolution.

  • Economic uses –

    • Pteridophytes are used for medicinal purposes and as soil-binders.
    • They are also frequently grown as ornamentals.

The pteridophytes are further classified into four classes:

 

  1. Psilopsida – e.g.,Psilotum.
  2. Lycopsida – e.g., Selaginella, Lycopodium.
  3. Sphenopsida – e.g., Equisetum.
  4. Pteropsida – e.g., Dryopteris, Pteris, Adiantum.

 

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GYMNOSPERMS

  • Plants in which the ovules are not enclosed by any ovary wall and remain exposed, both before and after fertilisation.
  • The seeds that develop post-fertilisation, are not covered (naked).
  • Plant body / structure –

    • Gymnosperms include medium-sized trees or tall trees and shrubs. One of the gymnosperms, the giant redwood tree Sequoia is one of the tallest tree species.
  • Roots –
    • The roots are generally tap roots.
    • Roots in Pinus have fungal association in the form of
    • in Cycas small specialized roots called coralloid roots are associated with N2- fixing cyanobacteria.
  • Stem –
    • The stems are unbranched (Cycas) or branched (Pinus, Cedrus).
  • Leaves –
    • The leaves may be simple or compound.
    • In Cycas the pinnate leaves persist for a few years.
    • The leaves in gymnosperms are well-adapted to withstand extremes of temperature, humidity and wind.
    • In conifers, the needle-like leaves reduce the surface area. Their thick cuticle and sunken stomata also help to reduce water loss.
  • Development of spores and gametophyte –

The gymnosperms are They produce haploid microspores and megaspores.

Spores are produced within sporangia that are borne on sporophylls, which are arranged spirally along an axis to form lax or compact strobili or cones.

Male –

The strobili bearing microsporophylls and microsporangia are called microsporangiate or male strobili.

The microspores develop into a male gametophytic generation which is highly reduced and is confined to only a limited number of cells.

This reduced male gametophyte is called a pollen grain.

Female –

The cones bearing megasporophylls with ovules or megasporangia are called macrosporangiate or female strobili.

The megaspore mother cell is differentiated from one of the cells of the nucellus.

The nucellus is protected by envelopes and the composite structure is called an ovule.

The megaspore mother cell divides meiotically to form four megaspores.

One of the megaspores enclosed within the megasporangium (nucellus) develops into a multicellular female gametophyte that bears two or more archegonia or female sex organs.

The multicellular female gametophyte is also retained within megasporangium.

  • The male or female cones or strobili may be borne on the same tree – bisexual/monoecious – Pinus Or on different trees – unisexual/dioecious – Cycas.
  • In gymnosperms, the male and the female gametophytes do not have an independent free-living existence. They remain within the sporangia retained on the sporophytes.
  • Pollination and fertilisation –

    • Pollination occur By air.
    • The pollen grain develop pollen tube on opening of ovule to carry male gametes towards archegonia in ovules.
    • Following fertilisation, zygote develops into an embryo and the ovules into seeds.
    • These seeds are not covered.

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ANGIOSPERMS (Flowering plants)

  • In the angiosperms pollen grains and ovules are developed in specialized structures called flowers.
  • In angiosperms, the seeds are enclosed by fruits.
  • The angiosperms are present in wide range of habitat.
  • Smallest angiosperm – Wolfia ; tallest angiosperm – Eucalyptus.
  • They provide us with food, fodder, fuel, medicines and several other commercially important products.
  • They are divided into two classes : the dicotyledons and the monocotyledons.
  • The dicotyledons are characterised by having two cotyledons in their seeds while the monocolyledons have only one.
  • The male sex organs in a flower is the stamen. Each stamen consists of a slender filament with an anther at the tip. The anthers, following meiosis, produce pollen grains.
  • The female sex organs in a flower is the pistil or the carpel. Pistil consists of an ovary enclosing one to many ovules. Within ovules highly reduced female gametophytes (embryosacs) are present. The embryo-sac formation is preceded by meiosis. Hence, each of the cells of an embryo-sac is haploid.

Each embryo-sac has a three-celled egg apparatus – one egg cell and two synergids, three antipodal cells and two polar nuclei.

The polar nuclei eventually fuse to produce a diploid secondary nucleus.

  • Pollen grain, after dispersal from the anthers, are carried by wind or various other agencies to the stigma of a pistil. This is termed as pollination.
  • The pollen grains germinate on the stigma and the resulting pollen tubes grow through the tissues of stigma and style and reach the ovule. The pollen tubes enter the embryo-sac where two male gametes are discharged.
  • Double fertilisation –

    • One of the male gametes fuses with the egg cell to form a zygote (syngamy).
    • The other male gamete fuses with the diploid secondary nucleus to produce the triploid primary endosperm nucleus (PEN). This process is known as Triple Fusion.
    • Because of the involvement of two fusions, this event is termed as double fertilisation.
  • Development of zygote –

    • The zygote develops into an embryo (with one or two cotyledons) and the PEN develops into endosperm which provides nourishment to the developing embryo.
    • The synergids and antipodals degenerate after fertilisation.
    • During these events the ovules develop into seeds and the ovaries develop into fruit.

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PLANT LIFE CYCLES AND ALTERNATION OF GENERATIONS

  • In plants, both haploid and diploid cells can divide by mitosis. This ability leads to the formation of different plant bodies – haploid and diploid and alternation of generation.
  • The haploid plant body produces gametes by mitosis. This plant body represents a gametophyte.
  • Following fertilisation the zygote also divides by mitosis to produce a diploid sporophytic plant body. Haploid spores are produced by this plant body by meiosis. These in turn, divide by mitosis to form a haploid plant body once again.
  • Different types of life cycle in plants –
  1. Haplontic life cycle

In this, Sporophytic generation is represented only by the one-celled zygote and there are no free-living sporophytes. Meiosis in the zygote results in the formation of haploid spores. The haploid spores divide mitotically and form the gametophyte. The dominant, photosynthetic phase in such plants is the free-living gametophyte.

e.g., Volvox, Spirogyra and some species of Chlamydomonas.(most of the algae)

  1. Diplontic life cycle

In this, diploid sporophyte is the dominant, photosynthetic, independent phase of the plant. The gametophytic phase is represented by the single to few-celled haploid gametophyte.

e.g., All seed-bearing plants i.e. gymnosperms and angiosperms, some algae like Fucus.

  1. Haplo-diplontic / Intermediate life cycle –

In this, both gametophytic and sporophytic phases are multicellular and often free living.

e.g., Bryophytes (dominant phase – gametophyte) and pteridophytes (dominanat phase – sporophyte), some algae like Ectocarpus, Polysiphonia.

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CHAPTER 3 – PLANT KINGDOM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Chapter 2- BIOLOGICAL CLASSIFICATION

CLASS 11th BIOLOGY NCERT NOTES

CHAPTER 2

BIOLOGICAL CLASSIFICATION

Earlier attempts for classification –

  • Aristotle was the earliest to attempt a more scientific basis for classification. He used simple morphological characters to classify plants into trees, shrubs and herbs. He divided animals into two groups, those which had red blood and those that did not.
  • Linnaeus gave a Two Kingdom system of classification with Plantae and Animalia

Five kingdom classification –

  • Proposed by R.H. Whittaker (1969).
  • The kingdoms defined by him were named Monera, Protista, Fungi, Plantae and
  • The main criteria for classification used by him include cell structure, thallus organisation, mode of nutrition, reproduction and phylogenetic relationships.

 

Table – Characteristics of the Five Kingdoms

Characters

Five Kingdoms

Monera Protista Fungi Plantae Animalia
Cell type Prokaryotic Eukaryotic Eukaryotic Eukaryotic Eukaryotic
Cell wall Noncellular (Polysaccharide+ amino acid) Present in some Present (without cellulose) Present (cellulose) Absent
Nuclear membrane Absent Present Present Present Present
Body organisation Cellular Cellular Multiceullar/ loose tissue Tissue/ organ Tissue/organ/ organ system
Mode of nutrition Autotrophic (chemosynthetic and photosynthetic)  and Heterotrophic (saprophyte/ parasite) Autotrophic  (Photosynthetic) and Heterotrophic Heterotrophic (Saprophytic/ Parasitic) Autotrophic  (Photosynthetic) Heterotrophic (Holozoic/ Saprophytic etc.)

 

 

Now a classification system has evolved which reflects not only the morphological, physiological and reproductive similarities, but is also phylogenetic (based on evolutionary relationships.)

KINGDOM MONERA

  • It consists of only Bacteria.
  • Bacteria live in all types of habitat, even in extreme habitats such as hot springs, deserts, snow and deep oceans or as parasite in or on organisms.
  • Though the bacterial structure is very simple, they are very complex in behaviour.
  • Some of the bacteria are autotrophic (they synthesise their own food from inorganic substrates).
  • They may be photosynthetic autotrophic or chemosynthetic autotrophic.
  • The majority of bacteria are heterotrophs. (They do not synthesise their own food but depend on other organisms or on dead organic matter for food.)
  • Classification of bacteria according to their shape –
  1. Spherical – Coccus
  2. rod-shaped – Bacillus
  3. comma-shaped – Vibrium
  4. spiral – Spirillum

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Bacteria are also classified into – archaebacteria and eubacteria.

 Archaebacteria: (Primitive Bacteria)

  • These bacteria live in some of the most harsh habitats such as extreme salty areas (halophiles), hot springs (thermoacidophiles) and marshy areas (methanogens).
  • Archaebacteria have a different cell wall structure and this feature is responsible for their survival in extreme conditions.
  • Methanogens are present in the guts of several ruminant animals such as cows and buffaloes and they are responsible for the production of methane (biogas) from the dung of these animals.

Eubacteria: (True Bacteria)

  • These are characterised by the presence of a rigid cell wall, and if motile, a flagellum.

    Cynobacteria

  • Cyanobacteria (blue-green algae) have chlorophyll–a similar to green plants and are photosynthetic autotrophs.
  • The cyanobacteria are unicellular, colonial or filamentous, marine or terrestrial algae.
  • The colonies are generally surrounded by gelatinous sheath.
  • They often form blooms in polluted water bodies.

    Nitrogen fixing bacteria –

  • They fix atmospheric nitrogen in specialised cells called heterocysts, g., Nostoc and Anabaena. (heterocyst provide anaerobic condition required for N2 fixatiom)

    Chemosynthetic autotrophic bacteria –

  • They oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production.
  • They play a great role in recycling nutrients like nitrogen, phosphorous, iron and sulphur.

    Heterotrophic bacteria –

  • They are the mostly important decomposers.
  • Some help in making curd from milk, production of antibiotics, fixing nitrogen in legume roots, etc.
  • Some are pathogens causing damage to human beings, crops, farm animals and pets.
  • Cholera, typhoid, tetanus, citrus canker are well known diseases caused by different bacteria.

    Reproduction in bacteria –

  • Bacteria reproduce mainly by fission.
  • Sometimes, under unfavourable conditions, they produce spores.
  • They also reproduce by a sort of sexual reproduction by adopting a primitive type of DNA transfer from one bacterium to the other. (Conjugation)

    Mycoplasmas –

  • These organisms completely lack a cell wall.
  • They are the smallest living cells known and can survive without oxygen.

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KINGDOM PROTISTA
 

  • All single-celled eukaryotes are placed under
  • Being eukaryotes, the protistan cell body contains a well defined nucleus and other membrane-bound organelles. Some have flagella or cilia.
  • Protists reproduce asexually and sexually by a process involving cell fusion and zygote formation.

Chrysophytes: (diatoms / golden algae /desmids).

  • Found in fresh water as well as in marine environments.
  • float passively in water currents (plankton). [plankton – passive flow, nekton – active flow]
  • Most of them are photosynthetic.
  • In diatoms the cell walls form two thin overlapping shells, which fit together as in a soap box.
  • The walls are embedded with silica and thus the walls are indestructible. Thus, diatoms have left behind large amount of cell wall deposits in their habitat; this accumulation over billions of years is referred to as ‘diatomaceous earth’.
  • Being gritty this soil is used in polishing, filtration of oils and syrups.
  • Diatoms are the chief ‘producers’ in the oceans.

Dianoflagellates:

  • They are mostly marine and photosynthetic.
  • They appear yellow, green, brown, blue or red depending on the main pigments present in their cells.
  • The cell wall has stiff cellulose plates on the outer surface.
  • Most of them have two flagella; one lies longitudinally and the other transversely in a furrow between the wall plates.
  • Red dianoflagellates (Gonyaulax) undergo such rapid multiplication that they make the sea appear red (red tides).
  • Toxins released by such large numbers may even kill other marine animals such as fishes.

Euglenoids:

  • Most of them are fresh water organisms found in stagnant water.
  • Instead of a cell wall, they have a protein rich layer called pellicle which makes their body flexible.
  • They have two flagella, a short and a long one.
  • Though they are photosynthetic in the presence of sunlight, when deprived of sunlight they behave like heterotrophs by predating on other smaller organisms. Therefore, they are known as connecting link between plant and animal.
  • The pigments of euglenoids are identical to those present in higher plants. Example: Euglena

Slime Moulds:

  • Slime moulds are saprophytic protists.
  • The body moves along decaying twigs and leaves engulfing organic material.
  • Under suitable conditions, they form an aggregation called plasmodium which may grow and spread over several feet.
  • During unfavourable conditions, the plasmodium differentiates and forms fruiting bodies bearing spores at their tips. The spores possess true walls. They are extremely resistant and survive for many years, even under adverse conditions. The spores are dispersed by air currents.

Protozoans

  • All protozoans are heterotrophs and live as predators or parasites.
  • There are four major groups of protozoans –

    (a) Amoeboid protozoans:

  • They move and capture their prey by pseudopodia (false feet).
  • Marine forms have silica shells on their surface.

e.g., Amoeba, Entamoeba (Parasite)

(b) Flagellated protozoans:

  • either free-living or parasitic.
  • They have flagella.
  • The parasitic forms cause diaseases such as sleeping sickness.

e.g., Trypanosoma.

(c) Ciliated protozoans:

  • Aquatic, actively moving organisms.
  • Have thousands of cilia.
  • They have a cavity (gullet) that opens to the outside of the cell surface.
  • The coordinated movement of rows of cilia causes the water laden with food to be steered into the gullet.

e.g., Paramoecium.

(d) Sporozoans:

  • These organisms have an infectious spore-like stage in their life cycle.

e.g., Plasmodium (malaria parasite).

 

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 KINGDOM FUNGI

  • organisms are heterotrophic.
  • Fungi are cosmopolitan and occur in air, water, soil and on animals and plants.
  • Structure –

    • fungi are filamentous (except yeast which is unicellular)
    • Their bodies consist of long, slender thread-like structures called hyphae. The network of hyphae is known as
    • Some hyphae are continuous tubes filled with multinucleated cytoplasm – these are called coenocytic hyphae. Others have septae or cross walls in their hyphae.
    • The cell walls of fungi are composed of chitin and polysaccharides.
  • Nutrition

    • Most fungi are heterotrophic and absorb soluble organic matter from dead substrates and hence are called saprophytes.
    • Those that depend on living plants and animals are called parasites.
    • They can also live as symbionts – in association with algae as lichens and with roots of higher plants as mycorrhiza.

 

  • Reproduction –

    • vegetative – fragmentation, fission and budding.
    • Asexual reproduction by spores called conidia or sporangiospores or zoospores.
    • sexual reproduction by oospores, ascospores and basidiospores.

The various spores are produced in distinct structures called fruiting bodies.

The sexual cycle involves the following three steps –

  1. Plasmogamy – Fusion of protoplasm between two motile or non-motile gametes.
  2. Karyogamy – Fusion of two nuclei.
  3. Meiosis – in zygote resulting in haploid spores.

When a fungus reproduces sexually, two haploid hyphae of compatible mating types come together and fuse.

  • In some fungi the fusion of two haploid cells immediately results in diploid cells (2n). However, in other fungi (ascomycetes and basidiomycetes), an intervening dikaryophase (2 nuclei per cell) occur. Later, the parental nuclei fuse and the cells become diploid. The fungi form fruiting bodies in which reduction division occurs, leading to formation of haploid spores.

Haploid spores →fusion begin →dikaryophase →nuclei fuse →diploid body →meiosis →haploid spores.

The morphology of the mycelium, mode of spore formation and fruiting bodies form the basis for the division of the kingdom into various classes.

Phycomycetes

  • Found in aquatic habitats and on decaying wood in moist and damp places or as obligate parasites on plants.
  • The mycelium is aseptate and coenocytic.
  • Asexual reproduction takes place by zoospores (motile) or by aplanospores (non-motile). These spores are endogeneously produced in sporangium.
  • Zygospores are formed by fusion of two gametes. These gametes are similar in morphology (isogamous) or dissimilar (anisogamous or oogamous).

e.g., Mucor,Rhizopus (the bread mould) and Albugo (the parasitic fungi on mustard).

Ascomycetes (Sac fungi)

  • multicellular (except Yest)
  • Mycelium is branched and septate.
  • The asexual spores are conidia produced exogenously on the special mycelium called conidiophores.
  • Sexual spores are called ascospores which are produced endogenously in sac like asci. These asci are arranged in different types of fruiting bodies called ascocarps.
  • Neurospora is used extensively in biochemical and genetic work.
  • Many members like morels and buffles are edible and are considered delicacies.

e.g., yeast, Aspergillus,Penicillium,Claviceps and Neurospora.

Basidiomycetes (mushrooms, bracket fungi, puff balls)

  • They grow in soil, on logs and tree stumps and in living plant bodies as parasites, e.g., rusts and smuts.
  • The mycelium is branched and septate.
  • The asexual spores are generally not found.
  • vegetative reproduction commonly by fragmentation.
  • The sex organs are absent,
    • Plasmogamy is brought about by fusion of two vegetative or somatic cells of different strains or genotypes.
    • The resultant structure is dikaryotic which ultimately gives rise to basidium.
    • Karyogamy and meiosis take place in the basidium producing four basidiospores. The basidiospores are exogenously produced on the basidium. The basidia are arranged in fruiting bodies called basidiocarps.

e.g., Agaricus (mushroom), Ustilago (smut) and Puccinia (rust fungus).

Deuteromycetes (imperect fungi)

  • Commonly known as imperfect fungi because only the asexual or vegetative phases of these fungi are known.
  • When the sexual forms of these fungi were discovered they were moved into classes they rightly belong to.
  • The deuteromycetes reproduce only by asexual spores known as conidia.
  • The mycelium is septate and branched.
  • Some members are saprophytes or parasites while a large number of them are decomposers of litter and help in mineral cycling.

e.g., Alternaria, Colletotrichum and Trichoderma.

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 KINGDOM PLANTAE

  • Includes all eukaryotic chlorophyll containing organisms.
  • Few members are partially heterotrophic such as the insectivorous plants or parasites.

e.g., Insectivorous plants – Bladderwort and Venus fly trap.

          Parasitic Plants – Cuscuta.

  • cell wall mainly made of cellulose.
  • Plantae includes algae, bryophytes, pteridophytes, gymnosperms and angiosperms.
  • Life cycle of plants has two distinct phases – the diploid sporophytic and the haploid gametophytic – that alternate with each other. This phenomenon is called alternation of generation.

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KINGDOM ANIMALIA

  • They directly (herbivore) or indirectly (carnivore) depend on plants for food.
  • They digest their food in an internal cavity and store food reserves as glycogen or fat.
  • Their mode of nutrition is holozoic – by ingestion of food.
  • They follow a definite growth pattern and grow into adults with definite shape and size.
  • Higher forms show elaborate sensory and neuromotor mechanism.
  • Most of them are capable of locomotion.
  • The sexual reproduction is by copulation of male and female followed by embryological development.

 

VIRUSES, VIROIDS AND LICHENS

  • Some acellular organisms like viruses, viroids and lichens are not included in the five kingdom classification of Whittaker.

Viruses

  • Viruses did not find a place in classification since they are not truly ‘living’.
  • The viruses are non-cellular organisms that are characterized by having an inert crystalline structure outside the living cell.
  • Once they infect a cell they take over the machinery of the host cell to replicate themselves, killing the host.
  • The name virus that means venom or poisonous fluid was given by Pasteur.
  • D.J. Ivanowsky (1892) recognised certain microbes as causal organism of the mosaic disease of tobacco. These were found to be smaller than bacteria because they passed through bacteria-proof filters.
  • M.W. Beijerinek (1898) demonstrated that the extract of the infected plants of tobacco could cause infection in healthy plants and called the fluid as Contagium vivum fluidum (infectious living fluid).
  • W.M. Stanley (1935) showed that viruses could be crystallised and crystals consist largely of proteins. They are inert outside their specific host cell.
  • Viruses are obligate parasites.
  • In addition to proteins viruses also contain genetic material that could be either RNA or DNA. No virus contains both RNA and DNA.
  • A virus is a nucleoprotein and the genetic material is infectious.
  • In general, viruses that infect plants have single stranded RNA and viruses that infect animals have either single or double stranded RNA or double stranded DNA.
  • Bacterial viruses or bacteriophages (viruses that infect the bacteria) are usually double stranded DNA viruses.
  • The protein coat called capsid made of small subunits called capsomeres, protects the nucleic acid.
  • These capsomeres are arranged in helical or polyhedral geometric forms.
  • Viruses cause diseases like mumps, small pox, herpes, influenza, AIDS.
  • In plants, the symptoms can be mosaic formation, leaf rolling and curling, yellowing and vein clearing, dwarfing and stunted growth.

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Viroids

  • Dicovered by T.O. Diener in 1971.
  • It was smaller than viruses and caused potato spindle tuber disease.
  • It was found to be a free RNA; it lacked the protein coat that is found in viruses, hence the name viroid.
  • The RNA of the viroid was of low molecular weight.

 Lichens

  • Lichens are symbiotic associations (mutually useful) between algae and fungi.
  • The algal component is known as phycobiont and fungal component as mycobiont, which are autotrophic and heterotrophic, respectively.
  • Algae prepare food for fungi and fungi provide shelter and absorb mineral nutrients and water for its partner.
  • So close is their association that if one saw a lichen in nature one would never imagine that they had two different organisms within them.
  • Lichens are very good pollution indicators – they do not grow in polluted areas.(Sulphur indicator).

 

Full file in Pdf form is below –

CHAPTER 2 – BIOLOGICAL CLASSIFICATION

 

CHAPTER 1 – THE LIVING WORLD

excerpt of chapter 1.
all important points presented in form of short notes.
notes in form of word file also given below.

CHAPTER 1

THE LIVING WORLD

Distinctive characteristics exhibited by living organisms –

  • Growth,
  • Reproduction,
  • Ability to sense environment and mount a suitable response,
  • Metabolism,
  • Ability to self-replicate,
  • Self-organise,
  • Interact and
  • Emergence.

Growth –

Increase in mass and increase in number of individuals are twin characteristics of growth.

A multicellular organism grows by cell division.

In plants, this growth by cell division occurs continuously throughout their life span while in animals, this growth is seen only up to a certain age.

Unicellular organisms also grow by cell division.

Non-living objects also grow if we take increase in body mass as a criterion for growth. However, this kind of growth exhibited by non-living objects is by accumulation of material on the surface while in living organisms, growth is from inside.

Growth, therefore, cannot be taken as a defining property of living organisms.

Reproduction –

In multicellular organisms, reproduction refers to the production of progeny possessing features more or less similar to those of parents.

Organisms reproduce by sexual and asexual means.

Some methods of asexual reproduction –

  • Spores – Fungi.
  • Budding – yeast and hydra.
  • True regeneration – Planaria (flat worms).
  • Fragmentation – The fungi, the filamentous algae, the protonema of mosses.

In unicellular organisms, reproduction is synonymous with growth.

There are many organisms which do not reproduce (mules, sterile worker bees, infertile human couples, etc). Hence, reproduction also cannot be an all-inclusive defining characteristic of living organisms.

 Metabolism –

The sum total of all the chemical reactions occurring in our body is metabolism.

All plants, animals, fungi and microbes exhibit metabolism.

Metabolic reactions can be demonstrated outside the body in cell-free systems. An isolated metabolic reaction(s) outside the body of an organism, performed in a test tube is neither living nor non-living.

Hence, while metabolism is a defining feature of all living organisms without exception, isolated metabolic reactions in vitro are not living things but surely living reactions.

Cellular organization –

Cellular organization of body is defining feature of all life forms as body of all living being consist of cell(s).

Cell is smallest independent possible unit of life which can sustain itself.

Ability to sense environment and mount a suitable response –

The most obvious and technically complicated feature of all living organisms is this ability to sense their surroundings or environment and respond to these environmental stimuli.

We sense our environment through our sense organs.

All organisms, from the prokaryotes to the most complex eukaryotes can sense and respond to environmental cues.

All organisms are aware of their surroundings.

Human being is the only organism who is aware of himself, i.e., has self-consciousness.

      Consciousness therefore, is the defining property of living organisms.

All living phenomena are due to underlying interactions. Properties of tissues are not present in the constituent cells but arise as a result of interactions among the constituent cells. Similarly, properties of cellular organelles are not present

in the molecular constituents of the organelle but arise as a result of interactions among the molecular components  comprising the organelle.

These interactions result in emergent properties at a higher level of organisation. This phenomenon is true in the hierarchy of organizational complexity at all levels.

Therefore, we can say that living organisms are self-replicating, evolving and self-regulating interactive systems capable of responding to external stimuli.

Diversity In The Living World

Our earth has high bio-diversity as it has about 1.7-1.8 million species.

Different organisms are known by their local names in different areas so there is a need to standardise the naming of living organisms such that a particular organism is known by the same name all over the world. This process is called nomenclature.

Nomenclature or naming is only possible when the organism is described correctly and we know to what organism the name is attached to. This is identification.

For plants, scientific names are based on agreed principles and criteria, which are provided in International Code for Botanical Nomenclature (ICBN).

For animal there is International Code of Zoological Nomenclature (ICZN).

The scientific names ensure that each organism has only one name.

 Universally accepted principles to provide scientific names

  • Each name has two components – the Generic name and the specific epithet. This system of providing a name with two components is called Binomial nomenclature – given by Carolus Linnaeus.

e.g., mango – Mangifera indica. (Mangifera – genus name, indica – species epithet).

  • Biological names are generally in Latin and written in italics.
  • Both the words in a biological name, when handwritten, are separately underlined, or printed in italics to indicate their Latin origin.
  • The first word denoting the genus starts with a capital letter while the specific epithet starts with a small letter.
  • Name of the author appears after the specific epithet, i.e., at the end of the biological name and is written in an abbreviated form, e.g., Mangifera indica

 

Classification is the process by which anything is grouped into convenient categories based on some easily observable characters.

The scientific term for these categories is taxa.

All living organisms can be classified into different taxa. This process of classification is taxonomy.

External and internal structure, along with the structure of cell, development process and ecological information of organisms are essential and form the basis of modern taxonomic studies.

characterisation, identification, classification and nomenclature are the processes that are basic to taxonomy.

The branch of study of knowing more about different kinds of organisms, their diversities and the relationships among them is known as systematics.

Linnaeus used Systema Naturae as the title of his publication.

 Taxonomic Categories

Classification involves hierarchy of steps in which each step represents a rank or category. Since the category is a

part of overall taxonomic arrangement, it is called the taxonomic category and all categories together constitute the taxonomic hierarchy.

Each category, referred to as a unit of classification, represents a rank and is commonly termed as taxon.

Species → Genus → Family → Order → Class → Phylum or Division → Kingdom

Common Name Biological Name Genus Family Order Class Phylum/ Division
Man Homo sapiens Homo Hominidae Primata Mammalia Chordata
Housefly Musca domestica Musca Muscidae Diptera Insecta Arthropoda
Mango Mangifera indica Mangifera Anacardiaceae Sapindales Dicotyledonae Angiospermae
Wheat Triticum aestivum Triticum Poaceae Poales Monocotyledonae Angiospermae

TAXONOMICAL AIDS

Herbarium

Herbarium is a store house of collected plant specimens that are dried, pressed and preserved on sheets.

These specimens, along with their descriptions on herbarium sheets, become a store house or repository for future use.

The herbarium sheets also carry a label providing information about date and place of collection, English, local and botanical names, family, collector’s name, etc.

Botanical Gardens

These specialised gardens have collections of living plants for reference.

Plant species in these gardens are grown for identification purposes and each plant is labelled indicating its botanical/scientific name and its family.

Some famous botanical gardens – Kew (England), Indian Botanical Garden, Howrah (India), National Botanical Research Institute, Lucknow (India).

Museum

Biological museums are generally set up in educational institutes such as schools and colleges.

Museums have collections of preserved plant and animal specimens for study and reference.

Zoological Parks

These are the places where wild animals are kept in protected environments under human care and which enable us to learn about their food habits and behaviour.

Key

Key is taxonomical aid used for identification of plants and animals based on the similarities and dissimilarities.

The keys are based on the contrasting characters generally in a pair called couplet.

It represents the choice made between two opposite options. This results in acceptance of only one and rejection of the other.

Each statement in the key is called a lead.

Separate taxonomic keys are required for each taxonomic category such as family, genus and species for identification purposes.

Keys are generally analytical in nature.

Flora, Manuals, Monographs, Catalogues

Flora contains the actual account of habitat and distribution of plants of a given area. These provide the index to the plant species found in a particular area.

Manuals are useful in providing information for identification of names of species found in an area.

Monographs contain information on any one taxon.

 

 

Full notes in pdf file –

CHAPTER 1 – LIVING ORGANISM