Class 9 Science Chapter 7

Diversity in living organisms


Page 80
Question 1. Why do we classify organisms?
Answer: For easier and convenient study we classify organisms.

Question 2. Give three examples of the range of variations that you see in life-forms around you.
Answer:
(a) Small cat and big cow
(b) Grass and banyan tree
(c) Black crow and green parrot

Page 82
Question 1. 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?
Answer: Classification based on living place is more basic as there can be wide variations in organisms living in a given place.

Question 2. What is the primary characteristic on which the first division of organisms is made?
Answer: 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.

Question 3. On what bases are plants and animal’ out into different categories?
Answer: Mode of nutrition and presence or absence of cell walls.

Page 83
Question 1. Which organisms are called primitive and how are they different from the so-called – advanced organisms?
Answer: 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.

Question 2. Will adiKznced organisms be the same as complex organisms? Why? t
Answer: Yes, advanced organisms means greater degree of evolution which leads to more complexity.

Page 85
Question 1. Whaf is the criterion for classification of organisms as belonging to kingdom Monera or Protista?
Answer: It is the presence or absence of a well defined nucleus. Monera has no nuclear membrane, while Protista shows well defined nucleus.

Question 2. In which kingdom will you place an organism which is single-celled, eukaryotic and
photosynthetic?
Answer: Protista.

Question 3. 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?
Answer: 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 88
Question 1. Which division among plants has the simplest organisms?
Answer: Thallophyta or algae.

Question 2. How are pteridophytes different from the phanerogams?
Answer: Pteridophytes have naked embryo and inconspicuous reproductive organ whereas — phanerogams have well-differentiated reproductive organs and covered embryo.

Question 3. How do gymnosperms and angiosperms differ from each other?
Answer: Seeds are naked in Gymnosperms and are covered in angiosperms.

Page 94
Question 1. How do poriferan animals differ from coelenterate animals?
Answer: Animals from Porifera show cellular level of organisation, while those from Coelenterata show tissue level of organisation.
In Porifera there is no division of labour, while in Coelenterata some division of labour is seen.
Porifera do not have coelom, while coelenterata have coelom.

Question 2. How do annelid animals differ from arthropods?
Answer:


Question 3. What are the differences between amphibians and reptiles?
Answer:


Question 4. What are the differences between animals belonging to the Aves group and those in the mammalia group?
Answer:

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