Saturday, 30 January 2016


1) What are the advantages of classifying organisms?

ANSWER:-The advantages of classifying organisms:
i) It makes the study of different kinds of organisms much easier.
ii)It tells us about the inter- relationship among the various organisms.
iii)It helps us understanding the evolution of organisms.
iv)It helps environmentalists to develop new methods of conservation of plants and animals.

2) How would you choose between two characteristics to be used for developing a hierarchy in classification?

ANSWER:-We choose that characteristics which depends on the first characteristics and determines the rest variety.

3) Explain the basis for grouping organisms into five kingdoms.

ANSWER:-The basis for grouping organisms into five kingdoms is:
(i) Nature of the cells, i.e., either prokaryotic or eukaryotic cells.
(ii) Number of cells, i.e., unicellular (a cell living singly) or multicellular (complex organisms).
(in) Presence or absence of cell wall.
(iv) Mode of nutrition, i.e., whether they prepare their own food or get their food
from outside.

4) What are the major divisions in the Plantae? What is the basis for these divisions?

ANSWER:-The major divisions in Kingdom Plantae are:
The following points constitute the basis of these divisions:
Whether the plant body has well differentiated, distinct components.
whether the differentiated plant body has special tissues for the transport of water and other substances.
The ability to bear seeds.
Whether the seeds are enclosed within fruits.

5) How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?

ANSWER:-The criteria for deciding divisions in plants are the presence or absence of seeds and flowers, differentiation of body parts, presence or absence of specialized vascular tissues and nature of the seed. The criteria for subdivisions among animals are the presence or absence of notochord and coelom, position of nerve cord, gill slits, body segmentation, habitat and oviparity or viviparity.

6) Explain how animals in Vertebrata are classified into further subgroups.

ANSWER:-Animals in Vertebrata are classified into five classes:

(i) Class Pisces: This class includes fish such as Scoliodon, tuna, rohu, shark, etc. These animals mostly live in water. Hence, they have special adaptive features such as a streamlined body, presence of a tail for movement, gills, etc. to live in water.

(ii) Class Amphibia: It includes frogs, toads, and salamanders. These animals have a dual mode of life. In the larval stage, the respiratory organs are gills, but in the adult stage, respiration occurs through the lungs or skin. They lay eggs in water.

(iii) Class Reptilia: It includes reptiles such as lizards, snakes, turtles, etc. They usually creep or crawl on land. The body of a reptile is covered with dry and cornified skin to prevent water loss. They lay eggs on land.

(iv) Class Aves: It includes all birds such as sparrow, pigeon, crow, etc. Most of them have feathers. Their forelimbs are modified into wings for flight, while hind limbs are modified for walking and clasping. They lay eggs.

(v) Class Mammalia: It includes a variety of animals which have milk producing glands to nourish their young ones. Some lay eggs and some give birth to young ones. Their skin has hair as well as sweat glands to regulate their body temperature.