NCERT solutions for class 9 science : Intext Solutions

Chapter 07-Diversity in Living Organisms-Intext Solutions

Intext Questions Page Number-80
Q.1. Why do we classify organisms?
Answer. There are more than a million kinds of living things exhibiting an infinite variety of form, structure and living places. It is practically not possible to examine and study every organism separately at individual level. It is, therefore, advisable to study the diversity of organism by classifying them in proper order.
Q.2. Give three examples of the range of variations that you see in life forms around you.
Answer. The range of variation in life forms is vast. Most common of these are size (living fern ranges from microscopic bacteria to giant blue whale), colour (living beings range from colourless or even transparent worms to brightly coloured birds and flowers), and life span (like insects which live for only few days while pine trees live for thousand of years).
Intext Questions Page Number 82
Q.1. Which do you think is a more basic characteritic for classifying organisms?
(a) the place where they live
(b) the kind of cells they are made of, why?
Answer. (b) The kind of cells they are made of :
In a place, very different types of organisms may live. They may not have similarities except common habitat. Thus, habitat cannot be basic characteristic for the classification of organism into groups.
Q.2. What is the primary characteristic on which the first division of organisms is made ?
Answer. The primary characteristic used for making the first division of organisms is: “Whether the organisms are prokaryotic or eukaryotic.”
Q.3. On what bases are plants and animals put into different categories?
Answer. Plants and animals are put into different categories on the basis of whether they can produce their own food or not. Being able to produce one’s own food versus having to get food from outside would make very different body designs necessary. In this way, plants and animals have been categorised into different groups.

Intext Questions Page Number 83
Q.1. Which organisms are called primitive and how are they different from the so-called advanced organisms?
Answer. The organisms which have not changed much and bear ancient body designs are known as primitive organisms. On the other hand, advanced organisms have acquired the specific body design relatively recently. Primitive organisms bear simple body design due to primitive structure and advanced organisms bear complex structure.
Q.2. Will advanced organisms be the same as complex organisms? Why?
Answer. Yes. The complex organisms are comparatively more advanced as compared to simple organisms.
It is because the complexity of organisms has increased over evolutionary time.

Intext Questions Page Number 85
Q.1. What is the criterion for classification of organisms as belonging to kingdom Monera or Protista?
Answer. Monerans are unicellular and prokaryotic. Nucleus is not well organissed and membrane bound organelles are not present.
Protists are unicellular and eukaryotic. They bear well defined nucleus and membrane bound organelles.
Q.2. In which kingdom will you place an organism which is single celled, eukaryotic and photosynthetic?
Answer. Kingdom—Protista.
Q.3. In 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 or organisms?
Answer. In the hierarchy of classification, species will have the smallest number of organisms with a maximum of characteristics in common and kingdom will have the largest number of organisms.
Intext Questions Page Number 88

Q.1. Which division among plants has the simplest organisms?
Answer. The organisms belonging to division Thallophyta has the simplest plants.
Q.2. How are pteridophytes different from the phanerogams?
Answer. The plants belonging to pteridophytes do not produce seeds whereas those belonging to phanerogams produce seeds.
Q.3. How do gymnosperms and angiosperms differ from each other?

Intext Questions Page Number. 94
Q.1. How do poriferan animals differ from coelenterate animals?

Q.2. How do annelid animals differ from arthropods?

Q.3. What are the differences between amphibiand and reptiles?

Q.4. What are the differences between animals belonging to the aves group and those in the mammalia group?