Chapter 7. Diversity in Living Organisms

Internal Questions :

1. Why do we classify organisms?

Answer: We classify organisms to organize and understand the vast diversity of life on Earth. It helps us study, communicate about, and learn from different species.
2. Give three examples of the range of variations that you see in life forms around you.

Answer:  Three examples of variations in life-forms are:

Different colors of flowers in a garden.

Various shapes and sizes of leaves on trees.

Various breeds of dogs, each with unique traits.

Internal Questions :

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 : (b) The kind of cells they are made of is a more basic characteristic for classifying organisms because it reflects fundamental differences in the biology and structure of living things. Organisms with similar cell types share common biological processes, while their habitat can change without altering their fundamental nature.
2. What is the primary characteristic on which the broad division of organisms is made?

Answer: The primary characteristic for the broad division of organisms is whether they are unicellular (made of a single cell) or multicellular (made of multiple cells).
3. On what bases are plants and animals put into different categories?

Answer: Plants and animals are categorized into different groups primarily based on the presence of cell walls. Plants have cell walls, while animals do not.

Internal Questions :

1. Which organisms are called primitive and how are they different from the so-called advanced organisms?

Answer: Organisms referred to as "primitive" are typically single-celled or simple multicellular organisms with basic structures and functions. They lack specialized tissues and complex organs. In contrast, "advanced" organisms are often multicellular, possess specialized tissues and organs, and exhibit more complex behaviors and adaptations.
2. Will advanced organisms be the same as complex organisms? Why?

Answer: Yes, advanced organisms are often the same as complex organisms. This is because advanced organisms tend to have complex structures, specialized organs, and intricate functions, making them more complex in terms of biology and organization.

Internal Questions :

1. What is the criterion for classification of organisms as belonging to kingdom Monera or Protista?

Answer: The criterion for classifying organisms as belonging to the kingdom Monera or Protista is based on their cellular organization. Monera includes prokaryotic organisms, which lack a nucleus and membrane-bound organelles, while Protista consists of eukaryotic organisms with a nucleus and membrane-bound organelles within their cells.
2. In which kingdom will you place an organism which is single celled, eukaryotic and photosynthetic?

Answer: An organism that is single-celled, eukaryotic, and photosynthetic would be classified under the kingdom Protista. The Protista kingdom consists of diverse eukaryotic organisms that do not fit into other kingdoms such as Plantae, Fungi, or Animalia. It includes various single-celled organisms like algae and protozoans.
3. 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 ?

Answer: In the hierarchy of classification, the grouping with the smallest number of organisms and maximum common characteristics is the species. A species consists of individuals that share similar physical traits and can reproduce with one another. The largest grouping with the maximum number of organisms is the kingdom, which encompasses a wide range of species with varying characteristics.

Internal Questions :

1. Which division among plants has the simplest organisms?

Answer: Thallophyta or Algae .
2. How are pteridophytes different from the phanerogams?

Answer: Pteridophytes are non-flowering, seedless plants that reproduce via spores. Phanerogams (or angiosperms) are flowering plants that produce seeds within fruits, often enclosed by protective tissues.
3. How do gymnosperms and angiosperms differ from each other?

Answer: Gymnosperms produce seeds in cones and lack true fruits. Angiosperms produce seeds within fruits. Gymnosperms include conifers, while angiosperms are flowering plants with enclosed seeds.

Internal Questions :

1. How do poriferan animals differ from coelenterate animals?

Answer: Poriferan animals, like sponges, lack true tissues and organs. Coelenterate animals, such as jellyfish, have true tissues and a simple body structure with tentacles and a central digestive cavity.
2. How do annelid animals differ from arthropods?

Answer:  The differences between annelid animals and arthropods:

Characteristic	Annelid Animals (e.g., Earthworms)	Arthropods (e.g., Insects)
Body Structure	Segmented and soft	Exoskeleton, hard and jointed
Appendages (e.g., legs)	Typically absent	Present, jointed
Skeleton	Internal	External (exoskeleton)
Number of Legs	Varies, but typically none	Typically six or more

3. What are the differences between amphibians and reptiles?

Answer:  The differences between amphibians and reptiles are:

Characteristic	Amphibians	Reptiles
Skin	Moist, permeable skin	Dry, scaly skin
Life Cycle	Typically have an aquatic larval stage (e.g., tadpole)	Direct development, no aquatic larval stage
Temperature Regulation	Cold-blooded (ectothermic)	Cold-blooded (ectothermic), but often more heat-tolerant than amphibians

4. What are the differences between animals belonging to the Aves group and those in the mammalian group?

Answer: The differences between animals in the Aves (birds) group and the mammalian group:

Characteristic	Aves (Birds)	Mammals
Body Covering	Feathers	Hair or fur
Reproduction	Lay eggs (oviparous)	Give birth to live young (viviparous or ovoviviparous)
Lactation	Do not produce milk	Produce milk for offspring

Class 9 Diversity in living Organisms Exercises :

1. What are the advantages of classifying organisms?

Answer:  The advantages of classifying organisms are:

(i) It helps organize the vast diversity of life into manageable groups for study.

(ii) It aids in the identification and naming of species.

(iii) It provides insights into evolutionary relationships and common ancestry among organisms.               

2. How would you choose between two characteristics to be used for developing a hierarchy in classification?

Answer : When choosing between two characteristics for developing a hierarchy in classification, several factors can be considered. These include the relevance of the characteristics to the overall diversity and relationships among organisms, the consistency and stability of the characteristics across different species, and the ability of the characteristics to differentiate and group organisms effectively.
3. Explain the basis for grouping organisms into five kingdoms.

Answer:  Organisms are grouped into five kingdoms based on fundamental differences in their cell structure, nutrition, and organization. The criteria for these groupings include:

Cell Type: Prokaryotic cells (Bacteria) vs. eukaryotic cells (Protista, Fungi, Plantae, Animalia).

Nutrition: Autotrophic (Plantae) vs. heterotrophic (Animalia, Fungi) vs. a mix of both (Protista).

Cell Wall: Presence (Plantae, Fungi, Bacteria) vs. absence (Animalia, Protista). These kingdoms help organize and categorize the wide variety of life forms on Earth based on these fundamental characteristics.

4. What are the major divisions in the Plantae? What is the basis for these divisions?

Answer:  The major divisions in the Plantae kingdom are Bryophyta (mosses and liverworts), Pteridophyta (ferns and fern allies), Gymnospermae (conifers and related plants), and Angiospermae (flowering plants).

These divisions are based on the reproductive characteristics and complexity of plant structures. Bryophyta lack true roots, stems, and leaves. Pteridophyta have vascular tissues but do not produce seeds. Gymnospermae produce naked seeds, while Angiospermae produce seeds enclosed within fruits.

5. How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?

Answer: The criteria for deciding divisions in plants are primarily based on structural characteristics, reproductive strategies, and the presence or absence of specific features like vascular tissues and seeds. In contrast, the criteria for deciding subgroups among animals are typically more diverse and encompass factors such as body symmetry, presence of a backbone, types of organs and systems, modes of reproduction, and evolutionary relationships. Animal classification considers a broader range of characteristics to capture the immense diversity within the animal kingdom.
6. Explain how animals in Vertebrata are classified into further subgroups.

Answer: Animals in Vertebrata (vertebrates) are classified into further subgroups based primarily on their skeletal features and other anatomical characteristics. The main subgroups are:

Piscs (Fishes): Cold-blooded vertebrates with scales and fins.

Amphibians: Cold-blooded vertebrates that typically have a larval aquatic stage.

Reptilia: Cold-blooded vertebrates with dry, scaly skin.

Aves (Birds): Warm-blooded vertebrates with feathers and beaks.

Mammals: Warm-blooded vertebrates with hair or fur, and they produce milk for their young.