NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms
1. Why do we classify organisms?
Solution:
By classifying organisms, it is easier and more convenient to study their characteristics. Similarities exhibited by various entities allow us to categorize different entities into a class and hence, study the group as a whole.
2. Give three examples of the range of variations that you see in life-forms around you.
Solution:
Listed below are a few ranges of variations observed in life-forms:
(a) Small frog to big whale
(b) Creeper to the eucalyptus tree
(c) Black cuckoo to colourful peacock
3. 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?
Solution:
The most basic classification of organisms should be established on the kind of cells they are made up of. This is because the habitat can have species with different characteristics living harmoniously whereas the entities with similar cell arrangement will exhibit equivalent characteristics.
4. What is the primary characteristic on which the broad division of organisms is made?
Solution:
The basic characteristic on which organisms are primarily divided is the nature of cells. It is broadly classified as prokaryotic cells and eukaryotic cells, which furthermore is classified into subclasses.
5. On what basis are plants and animals put into different categories?
Solution:
The following is the basis for categorization of plants and animals:
(a) The most fundamental consideration of classification is the presence and absence of a cell wall.
(b) The next important criterion is the mode of nutrition. The mechanism through which entities acquire their nutrients is used as the base for classification.
6. Which organisms are called primitive and how are they different from the so-called advanced organisms?
Solution:
Primitive organisms are the organisms that exhibit a very simple and basic cell arrangement, mechanism and structure and no division of labour is observed. Advanced organisms, on the other hand, are the organisms possessing millions of cells that are grouped into various organs performing different functionality such as mammals.
7. Will advanced organisms be the same as complex organisms? Why?
Solution:
Yes. Complex organisms are the same as advanced organisms. The consequence of advancement leads to multiple cell arrangements that operate uniquely.
8. What is the criterion for classification of organisms as belonging to kingdom Monera or Protista?
Solution:
One of the most significant differences in classification is the development of the nucleus. The ones with no nuclear membranes are defined to be Monera while the ones that have well-defined nuclei walls are Protista.
9. In which kingdom will you place an organism which is single-celled, eukaryotic and photosynthetic?
Solution:
Since the cell is photosynthetic, it must have a well-defined nucleus wall. Therefore, it needs to be placed in Protista kingdom.
10. In the hierarchy of classification, which grouping will have the smallest number of organisms with maximum common characteristics and which will have the largest number of organisms?
Solution:
(a) The organisms belonging to the Kingdom Monera will have the smallest number of organisms and with maximum characteristics in common.
(b) The organisms belonging to the Kingdom Animalia will have the largest number of organisms.
11. Which division among plants has the simplest organisms?
Solution:
Algae or Thallophyta has the simplest organisms among the plants.
12. How are pteridophytes different from the phanerogams?
Solution:
The following are the differences:
Pteridophytes |
Phanerogams |
They possess a naked embryo |
They possess a covered embryo |
Exhibit unclear reproductive organ |
Exhibit well-defined reproductive organ |
13. How do gymnosperms and angiosperms differ from each other?
Solution:
In gymnosperms, the seeds are naked while in angiosperms the seeds are covered.
14. How do poriferan animals differ from coelenterate animals?
Solution:
Listed below are the differences:
Porifera |
Coelenterata |
Division of labour is not noticed |
Division of labour is observed |
Cellular level of organization exhibited |
Tissue level of organization exhibited |
Coelom absent |
Coelom present |
15. How do annelid animals differ from arthropods?
Solution:
Listed below are the differences:
Annelida |
Arthropoda |
The entire body is segmented into rings |
Segmentation of body into head, abdomen and the thorax region |
Skeleton is absent |
Presence of exoskeleton |
Hermaphrodites |
Presence of different sexes, bisexual present |