Diversity in Living Organisms NCERT Solutions

Diversity in Living Organisms NCERT Solutions

INTEXT QUESTIONS AND ANSWERS

Page No. 80

Q1. Why do we classify organisms?
Ans. For easier and convenient study we classify organisms.

Q2. Give three examples of the range of variations that you see in life-forms around you.
Ans.
(a) A small cat and a big cow
(b) Grass and banyan tree
(c) Black crow and green parrot

Page No. 82

Q1. Which do you think is a more- basic characteristic for classifying organisms?
(a) the place where they live.
(b) the kind of cells they are made of. Why?
Ans. Classification based on living place is more basic as there can be wide variations in organisms living in a given place.

Q2. What is the primary characteristic on which the first division of organisms is made?
Ans. Nature of cell is the primary characteristics on which the first division of organisms is decided. Based on this criterion life forms can be classified into prokaryotes or eukaryotes.

Q3. On what bases are plants and animal’ out into different categories?
Ans. Mode of nutrition and presence or absence of cell walls.

Page No. 83

Q1. Which organisms are called primitive and how are they different from the so-called – advanced organisms?
Ans. Organisms with simple cellular structure and no division of labour are called
primitive.
Advanced organisms, like mammals, have millions of cells and there are different organs and organ system for different biological functions.

Q2. Will advanced organisms be the same as complex organisms? Why?
Ans. Yes, advanced organisms mean a greater degree of evolution which leads to more complexity.

Page No. 85

Q1. What is the criterion for classification of organisms as belonging to kingdom Monera or Protista?
Ans. It is the presence or absence of a well-defined nucleus. Monera has no nuclear membrane, while Protista shows well-defined nucleus.

Q2. In which kingdom will you place an organism which is single-celled, eukaryotic and
photosynthetic?
Ans. Protista.

Q3. In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics in common and which will have the largest number of organisms?
Ans. Organisms belonging to Kingdom Monera will have the small number of organisms with a maximum of characteristics in common. And kingdom Animalia will have the largest number of organisms.

Page No. 88

Q1. Which division among plants has the simplest organisms?
Ans. Thallophyta or algae.

Q2. How are pteridophytes different from the phanerogams?
Ans. Pteridophytes have a naked embryo and inconspicuous reproductive organ whereas phanerogams have well-differentiated reproductive organs and covered embryo.

Q3. How do gymnosperms and angiosperms differ from each other?
Ans. Seeds are naked in Gymnosperms and are covered in angiosperms.

Page No. 94

Q1. How do poriferan animals differ from coelenterate animals?
Ans.

Poriferan Coelenterate
●     No division of labour seen

●     Shows cellular level organisation

●     Do not have a coelom

●     Some division of labour is seen

●     Tissue level organisation observed

●     Coelom present

 

Q2. How do annelid animals differ from arthropods?
Ans.

Annelida Arthropods
● Body is segmented into rings

● No skeleton

● Hermaphrodite

● Body is segmented into head, abdomen and thorax

● Exoskeleton present

● Different sexes, bisexual present

 

Q3. What are the differences between amphibians and reptiles?
Ans.

Amphibia Reptilia
●     Has soft and moist skin

●     Amphibians in nature, breathe through the skin when in water

●     Uses lungs or gills to respire.

●     Can jump

●     Indirect development

●     Skin is hardened

●     Can live in water, but comes to land to take in oxygen

●     Uses lungs to respire

●     Movement through crawling

●     Direct development

 

Q4. What are the differences between animals belonging to the Aves group and those in the mammalia group?
Ans.

Aves Mammalia
●     Feathers cover the body

●     Has no teeth, instead has a beak

●     Its forelimbs are modified for flying

●     Contains hollow bones

●     Streamlined body

●     Body is covered with hair

●     Teeth present, beak absent

●     Forelimbs are used for various activities

●     Solid bones

●     No streamlined body (except in whales)

 

EXERCISES

Q1. What are the advantages of classifying organisms?
Ans.
Advantages of classification:

* Better categorization of living beings based on common characters.
* Easier study for scientific research.
* A better understanding of human’s relation to and dependency on other organisms.
* Helps in cross breeding and genetic engineering for commercial purposes.

Q2. How would you choose between two characteristics to be used for developing a hierarchy in classification?
Ans. Gross Character will “form the basis of a start of the hierarchy and fine character will form “the basis of further steps of single the hierarchy.
Example:
* Presence of vertebral column in human beings can be taken under vertebrata.
* Presence of four limbs makes them members of Tetrapoda.
* Presence of mammary glands keeps them under mammalia.

Q3. Explain the basis for grouping organisms into five kingdoms.
Ans. Basis Of Classification:
(a) Number of cells
(b) Layer of cells
(c) Presence or absence of cell wall
(d) Mode of nutrition
(e) Level Of organization

Q4. What are the major divisions in the Plantae? What is the basis for these divisions?
Ans. Major Divisions of Kingdom Plantae:

Division Basis of Classification
Thallophyta or Algae Like body
Bryophyta Body is divided into leaf and stem
Pteridophyta The body is divided into root, stem and leaf
Gymnosperm Seed-bearing, naked seeds
Gymnosperm Seed bearings covered seeds

 

Q5. How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?
Ans. In plants body, the basic structure is a major criterion based on which Thallophytes are different from Bryophytes. Apart from this absence or presence of seeds is another important criteria. Gymnosperms and angiosperms are further segregated based on if seeds are covered or not. It is clear that it is the morphological character which makes the basis for classification of plants.
In animals, classification is based on more minute structural variations. So in place of morphology, cytology forms the basis. Animals are classified based on layers of cells, presence or absence of coelom. Further higher the hierarchy animals are classified based on the presence or absence of smaller features, like the presence or absence of four legs.

Q6. Explain how animals in Vertebrata are classified into further subgroups.
Ans. Vertebrata is divided into two superclasses, viz. Pisces and Tetrapoda. Animals of Pisces have a streamlined body with fins and tails to assist in swimming. Animals of Tetrapoda have four limbs for locomotion.
Tetrapoda is further classified into the following classes:
(a) Amphibia: Are adapted to live in water and on land. Can breathe oxygen through the skin when under water.
(b) Reptilia: These sire crawling animals. Skin is hard to withstand extreme temperatures.
(c) Aves: Forelimbs are modified into wings to assist in flying. Beaks are present. Body is covered with feathers.
(d) Mammalia: Mammary glands present to nurture young ones. Skin is covered with hair. Most of the animals are viviparous.

 

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