Class 9 Science: Diversity and Classification – Extra Questions

Ans: C

Explanation: The term “primitive” in evolutionary terms refers to organisms that diverged earlier in the evolutionary history of life and generally retain more ancestral characteristics. These characteristics often include simpler body plans, less specialized structures, and fewer complex organ systems compared to more recently evolved organisms. Option A and B describe advanced evolutionary traits. Option D might be true for some organisms, but it’s not a defining characteristic of being “primitive” in an evolutionary sense.
Correct Option: C

Ans: C

Explanation: Mammals are characterized by the presence of mammary glands, which produce milk to nourish their young. Birds, while warm-blooded and often having feathers, do not produce milk. Feathers are also a characteristic of birds, not mammals. Laying of hard-shelled eggs is characteristic of birds (and reptiles, but not mammals in general, with exceptions like monotremes). Having a beak is a distinctive feature of birds.
Correct Option: C

Ans: C

Explanation: The question asks to identify a plant group that produces seeds, a characteristic absent in pteridophytes. Let’s analyze the options:
A. Mosses (Bryophytes) reproduce via spores and do not produce seeds.
B. Ferns (Pteridophytes) reproduce via spores and do not produce seeds.
C. Gymnosperms are seed-bearing plants, meaning they produce seeds.
D. Algae are non-vascular plants that reproduce primarily through spores or vegetative means and do not produce seeds.
Therefore, gymnosperms are characterized by the production of seeds, which are absent in pteridophytes.
Correct Option: C

Ans: A

Explanation: The fundamental difference between plant and animal cells that is a primary reason for their classification lies in their structural components. Plant cells possess a rigid cell wall made primarily of cellulose outside their cell membrane, providing structural support and protection. Animal cells lack a cell wall, making them more flexible and allowing for diverse shapes and functions. While options B and C describe important metabolic and storage differences, they are consequences of the fundamental structural differences. Option D is incorrect as both plant and animal cells are eukaryotic and possess a nucleus.
Correct Option: A

Ans: D

Explanation: Angiosperms are characterized by having flowers, which produce seeds enclosed within a protective fruit. Gymnosperms, on the other hand, have “naked seeds” that are not enclosed within a fruit and typically develop on cones or cone-like structures. Cones are a characteristic of gymnosperms, not angiosperms. Spores are involved in the reproductive cycles of both gymnosperms and angiosperms, but are not the distinguishing feature of angiosperms.
Correct Option: D

Ans: A

Explanation: Prokaryotic cells lack membrane-bound organelles, such as a nucleus, mitochondria, and endoplasmic reticulum, while eukaryotic cells possess these structures. This is a fundamental difference in their cellular organization. The method of reproduction, size of the organism, and number of chromosomes can vary within both prokaryotic and eukaryotic domains and are not defining fundamental differences between the two cell types themselves.
Correct Option: A

Ans: A

Explanation: Binomial nomenclature is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. This system was developed and popularized by Carl Linnaeus, a Swedish botanist, zoologist, and physician, in the 18th century. Charles Darwin is known for his theory of evolution by natural selection. Gregor Mendel is famous for his work on genetics and inheritance. Louis Pasteur is renowned for his discoveries in microbiology and the development of pasteurization.
Correct Option: A

Ans: D

Explanation: Cats, rats, and bats are all mammals. A defining characteristic of mammals is that they are endothermic (warm-blooded), have fur or hair, and the females produce milk to nourish their young. Option A is incorrect because only bats have wings for flight. Option B is incorrect because scales are characteristic of reptiles. Option C is incorrect because most mammals give birth to live young, though monotremes like the platypus lay eggs. Option D accurately describes a universal characteristic of mammals.
Correct Option: D

Ans: B

Explanation: Agaricus is a genus of mushrooms. Mushrooms are a type of fungus. Algae are photosynthetic organisms, gymnosperms and angiosperms are types of plants.
Correct Option: B

Ans: C

Explanation: Ostriches, penguins, and kiwis are all well-known examples of flightless birds. While ostriches are excellent runners, and some penguins can migrate, and kiwis are known for their distinctive four-toed feet, the most prominent shared characteristic among all three is their inability to fly.
Correct Option: C

Ans: D

Explanation: A natural system of classification groups organisms based on shared characteristics that reflect their evolutionary relationships. These characteristics include not only the complexity of cell structure and body structure but also their overall organization, physiological processes, and genetic makeup. Therefore, all the options listed are considered in a natural system of classification.
Correct Option: D

Ans: B

Explanation: Taxonomy is the scientific discipline concerned with the naming, defining, and classifying groups of biological organisms on the basis of shared characteristics. Demography studies human populations. Biology is the broader study of life.
Correct Option: B

Ans: C

Explanation: Fungal cells are eukaryotic, meaning they possess true nuclei and membrane-bound organelles, and their cell walls are indeed composed of chitin. Fungi also have a plasma membrane containing sterols, which are important for membrane fluidity and function. However, fungi are heterotrophic organisms and lack chlorophyll, which is the pigment used by plants and some other organisms for photosynthesis. Therefore, chlorophyll is a characteristic NOT found in fungal cells.
Correct Option: C

Ans: B

Explanation: Biological classification uses a system of hierarchical ranks to group organisms. These ranks, from broadest to most specific, include domain, kingdom, phylum, class, order, family, genus, and species. The general term for any of these groupings at any level of the hierarchy is “taxon” (plural: taxa). Families, orders, and kingdoms are all specific levels within this hierarchical system, not the general term for the groupings themselves.
Correct Option: B

Ans: C

Explanation: The larynx, also known as the voice box, is a cartilaginous structure in the neck of mammals that contains the vocal cords. When air is exhaled, it passes over the vocal cords, causing them to vibrate and produce sound. The pharynx is involved in swallowing and breathing but not directly in sound generation. The syrinx is the vocal organ found in birds, not mammals. The Adam’s apple is a prominent part of the larynx, but it is not the entire organ responsible for sound generation.
Correct Option: C

Ans: B

Explanation: Pteridophytes, unlike bryophytes, possess true vascular tissues (xylem and phloem) organized into vascular bundles. This allows for efficient transport of water and nutrients, supporting larger and more complex plant bodies. Bryophytes lack true vascular bundles and are generally smaller and simpler in structure. Archegonia are present in both groups. Motile antherozoids are also found in both bryophytes and pteridophytes. Alternation of generation is a characteristic of both plant groups, although the sporophyte generation is dominant in pteridophytes, while the gametophyte is dominant in bryophytes.
Correct Option: B

Ans: D

Explanation: Plants can be broadly classified into two groups based on whether they produce flowers or not. Phanerogams are plants that produce seeds, and this group includes flowering plants (angiosperms) and cone-bearing plants (gymnosperms). Cryptogams are plants that reproduce via spores and do not produce flowers or seeds. This group includes ferns, mosses, and algae. Dicots and monocots are further classifications within flowering plants (angiosperms) and therefore do produce flowers.
Correct Option: D

Ans: A

Explanation: Motile sperms, also known as antherozoids, are characteristic of organisms that reproduce sexually and require water for fertilization. In the given options, Funaria (a moss), ferns, and Cycas (a gymnosperm) all possess motile sperms. Rhizopus, however, is a fungus that reproduces asexually through spores and sexually through the fusion of gametangia, but it does not produce motile sperms.
Correct Option: A

Ans: B

Explanation: Algae are photosynthetic organisms, meaning they produce their own food. The primary form of energy storage in plants and many algae is starch, a complex carbohydrate. While algae can store proteins and fats, and some have glycogen, starch is generally considered their principal stored nutrient for energy.
Correct Option: B

Ans: A

Explanation: Autotrophs are organisms that can produce their own food, usually through photosynthesis. Parasites obtain nutrients from a living host, epiphytes grow on other plants but do not harm them, and saprophytes obtain nutrients from dead or decaying organic matter. Therefore, autotrophs are the organisms that produce their own food.
Correct Option: A