NCERT Solutions Class 9 Science Chapter 7 Diversity in Living Organisms
NCERT Solutions Class 9 Science Chapter 7 Diversity in Living Organisms: National Council of Educational Research and Training Class 9 Science Chapter 7 Solutions – Diversity in Living Organisms. NCERT Solutions Class 9 Science Chapter 7 PDF Download.
NCERT Solutions Class 9 Science Chapter 7: Overview
|Diversity in Living Organisms
NCERT Solutions Class 9 Science Chapter 7 – Diversity in Living Organisms
- Intext Questions
Q1. Why do we classify organisms?
Ans: A huge diversity of organisms are present on earth and it is not possible to study each organism individually. Hence classifying organisms in groups on the bases of similar characters makes it easier to study their characteristics.
Q2. Give three examples of the range of variations that you see in life-forms around you.
Ans:1.) Variation in color: colorless or transparent worms to brightly colored birds and flowers
2.) Variation in lifespan: pine tree lives for thousands of years and fruit flies live for a few days
3.) Variation in size: microorganisms like bacteria are a few micrometers long whereas blue whales are 100 meter long.
Q3. 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: The more basic classification of organisms is on the kind of cells they are made up of because the many different kinds of organisms can occupy the same habitat. If the kind of cells are same, they might show similar characters.
Q4. What is the primary characteristic on which the broad division of organisms is made?
Ans: The basic characteristic on which organisms are primarily divided is the presence or absence of a well-defined nucleus. On this basis organisms are classified as either prokaryotic or eukaryotic.
Q5. On what basis are plants and animals put into different categories?
Ans:The basis for categorization of plants and animals is as follows:
- Plants are autotrophic and animals are heterotrophic
- Plants cannot perform locomotion whereas animal can perform locomotion.
Q6. Which organisms are called primitive and how are they different from the so-called advanced organisms?
Ans: Primitive organisms or lower organism have a very old body design which has not changed much over time. Advanced organisms or higher organism have attained their body character recently.
Q7. Will advanced organisms be the same as complex organisms? Why?
Ans: Complex organisms have adapted changes which make them more complex than primitive organisms. The term advanced organisms refer to organisms that have changed as a result of evolution. As with evolution, change and complexity increase over time, resulting in more complex and advanced organisms. Hence, Advanced organisms may be the same as complex organisms.
Q8. What is the criterion for classification of organisms as belonging to kingdom Monera or Protista?
Ans: The criterion for classification of organisms as belonging to kingdom Monera or Protista is nuclear differentiation. Organisms belonging to division Monera do not have well defined nucleus and those belonging to Protista are unicellular eukaryotes.
Q9. In which kingdom will you place an organism which is single-celled, eukaryotic and photosynthetic?
Ans:An organism which is single-celled, eukaryotic and photosynthetic is Kingdom Protista.
Q10. 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?
Ans:In the hierarchy of classification organisms belonging to the Kingdom Monera will have the smallest number of organisms and with maximum common characteristics. On the other hand, In the hierarchy of classification organisms belonging to the Kingdom Animalia will have the largest number of organisms.
Q11. Which division among plants has the simplest organisms?
Ans: The Thallophyte have the simplest organisms among the plants division.
Q12. How are pteridophytes different from the phanerogams?
Ans: The following are the major differences betweenpteridophytes and phanerogams:
|The reproductive organs in Pteridophytesare very under developed
|Phanerogams are plants with well differentiated reproductive parts that make seeds
|They are seedless plants
|These plants produce seeds
|They are non-flowering plants
|They are flowering plants
Q13. How do gymnosperms and angiosperms differ from each other?
Ans: Gymnosperms are the plants which have naked seeds.On the other hand, angiosperms the seeds are covered.
Q14. How do poriferan animals differ from coelenterate animals?
Ans: The following are the major differences between Porifera and Coelenterate
|Body cavity is not present
|Body cavity is present
|The porifera have minimal differentiation and division into tissues
|Coelenterate show more body design differentiation as compared to porifera
Q15. How do annelid animals differ from arthropods?
Ans: The following are the major differences between annelids and arthropods
|There entire body is segmented in ring like metamers.
|The entire body is not segmented, there is only three segments head, thorax and abdomen.
|They do not have exoskeleton
|They have exoskeleton
|They do not have jointed appendages.
|They have jointed appendages.
Q16. What are the differences between amphibians and reptiles?
Ans: The following are the major differences between Amphibians and reptiles
|The skin is slimy, moist.
|The skin is hard because of presence of scales.
|Gills are present in larva whereas lungs are present in amphibian adults for respiration
|Reptiles have lungs for respiration
|They lay eggs in water
|They do not lay eggs in water
|Amphibians have three-chambered heart.
|Usually most reptiles have a three-chambered heart but crocodiles have four heart chambers.
Q17. What are the differences between animals belonging to the Aves group and those in the mammalian group?
Ans: The following are the major differences between Aves and mammalian group:
|The exoskeleton is covered with feathers
|The exoskeleton is covered with hair
|Aves are known to possess beak
|Mammals do not possess beak
|The forelimbs are modified for flight
|Mammals forelimbs are modified for fight
|The eggs are laid outside the body
|Most of mammals give birth to live young ones and do not lay eggs.
|Aves do not have teeth
|Most of mammals have teeth
- EXERCISE QUESTIONS:
Q1. What are the advantages of classifying organisms?
Ans: There are many advantages of classification of organisms:
- Classification helps us understand diversity in living organisms.
- Classification helps us study vast variety of organisms in a short time.
- Classification helps compare different organisms and their interaction
- Classification also helps us in understanding organisms which can be genetically modified
Q2. How would you choose between two characteristics to be used for developing a hierarchy in classification?
Ans: For classifying organisms one needs to define a character which will enable us to divide the organism in two distinct groups. The common characteristics are used to form sub-groups based on these. For example, presence of nuclear membrane is the most basic level of variation that exist in an organism.
Q3. Explain the basis for grouping organisms into five kingdoms.
Ans:1.) Five kingdom classifications are based on cell structure, mode and source of nutrition, and body organization.
2.) The presence or absence of membrane-bound organelles and nucleus, depending on whether the organisms are made up of prokaryotic or eukaryotic cells. Eukaryotes are then classified according to their cellular composition, Whether it’s a single cell or a multicellular organism. Organisms are categorised according to whether or not they have a cell wall.
3.) Finally, organisms having cell walls are classified according to their feeding mechanisms.
Q4. What are the major divisions in the Plantae? What is the basis of these divisions?
Ans:The five major divisions in plantae are: Thallophyta, Bryophyta, Pteridophyte, Gymnosperms, Angiosperms
The basis of classification is as follows:
1.) Thallophyta or Algae: simple plants with no well differentiated plant parts
2.) Bryophyta: plants having well differentiated plant parts but lack a well-defined vascular system
3.) Pteridophyta: plants having well differentiated plant parts,well-defined vascular system but do not produce seeds
4.) Gymnosperms: Plants having naked seed
5.) Angiosperms: Plants having coveredseed
Q5. How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?
Ans:1.) The levels of classification in plants are mainly based on morphological characters such the first level is whether the plant body has well differentiated, distinct plant parts. Other than this further classification is based on the weather plants have covered or naked seeds, or if plant body has tissues for water transport and food.
2.) On the other hand, animals are classified on the basis of cell structure and body design.
3.) This is mainly due to the fact that the basic designs differ based on the need to produce their own food (plants) or procure it (animals). As a result, these design features (having a skeleton, for example) should be used to create sub-groups rather than broad groups.
Q6. Explain how animals in Vertebrata are classified into further subgroups.
Ans: Vertebrata is further divided in 6 classes on the basis of the following differences
- Cyclostomata: the organism in this class are usually jawless, eel-like organisms with circular mouths. They do not possess scales and have slime skin.
- Pisces: these are aquatic vertebrates who have scales on the exoskeleton. The endoskeleton may have boles, cartilages or both. They perform respiration with help of gills.
- Amphibia: These organisms can reside on land as well as in water. They lack scales, and have slimy skin.
- Reptilia: these organisms in which exoskeleton is covered with scales. They usually lay eggs for giving birth to young ones but outside the waterbodies.
- Aves: These organisms have modified forelimbs for flight. The exoskeleton is covered with feathers and have a beak.
- Mammalia: The animals contain mammary glands. Their exoskeleton is covered with hair and are usually viviparous in nature.