Organisms and PopulationsNEET Botany · Class 12 · NCERT Chapter 4

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Keolado National Park, located in Rajasthan, is a famous wetland that attracts migratory birds from Siberia and other cold northern regions during the winter. NCERT XII chapter Organisms and Populations discusses this as an example of seasonal migration, so option (d) is correct.

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Detritivores are an important aspect of many ecosystem. They can live on any soil with organic component, including marine ecosystem.

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Populations of different species occurring in a habitat comprise the biotic community

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During competition, both partners are adversely affected.

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Gause’s principle of competitive exclusion states that no two species can occupy the same niche indefinitely for the same limiting resources.

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Mycorrhizae is a symbiotic association of fungi with roots of higher plants.

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The tropical rain forest have five vertical strata on the basis of height of plants. i.e. , ground vegetation, shrubs, short canopy trees, tall canopy trees and tall emergent trees.

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A population growing in a habitat with limited resources shows logistic growth curve. For logistic growth dN K – NrNdt K ⎛⎞= ⎜⎟⎝⎠ If K = N then K–N K = 0 ∴ the dN dt = 0, the population reaches asymptote.

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Natality refers to the birth rate, which is the number of births in a population over a given period. NCERT XII chapter Organisms and Populations defines natality as a key population attribute, so option (b) is correct.

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Niche refers to the functional role and position of a species within its environment, including its interactions with other species and its role in the ecosystem. NCERT XII chapter Organisms and Populations defines niche as the organism's role and function in its habitat, so option (d) is correct.

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Parasitism involves one organism benefiting at the expense of another, which is the principle behind the production of antibiotics, where bacteria or fungi produce substances that inhibit or kill other microorganisms. NCERT XII chapter Organisms and Populations describes this interaction, so option (a) is correct.

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In a growing population, the number of pre-reproductive individuals is typically higher than the number of reproductive individuals. This age structure supports population growth by ensuring a larger future reproductive pool, as described in NCERT XII chapter Organisms and Populations, so option (c) is correct.

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Species interaction is a characteristic of communities, not populations. Population attributes include sex ratio, natality, and mortality, as defined in NCERT XII chapter Organisms and Populations, so option (d) is correct.

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Resource partitioning allows competing species to coexist by using different parts of the same resource or different resources, reducing direct competition. NCERT XII chapter Organisms and Populations discusses this as a mechanism for species survival in the face of competition, so option (a) is correct.

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Amensalism is an interaction where one species is harmed (−) and the other is unaffected (0). NCERT XII chapter Organisms and Populations defines amensalism as a type of interspecific competition where one species suffers while the other is not affected, so option (a) is correct.

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The Founder effect is a type of genetic drift where a small group of individuals separates from a larger population and establishes a new population with a different gene pool. NCERT XII chapter Organisms and Populations explains that genetic drift, including the Founder effect, can lead to significant genetic changes in small populations, so option (d) is correct.

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- Allen's Rule: Polar seal (iv) - shorter limbs and extremities reduce heat loss.
- Physiological adaptation: Kangaroo rat (i) - conserves water in arid environments.
- Behavioural adaptation: Desert lizard (ii) - basks in the sun and burrows to regulate temperature.
- Biochemical adaptation: Marine fish at depth (iii) - produces antifreeze proteins to survive in cold, deep waters.

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If 8 Drosophila in a laboratory population of 80 died during a week, the death rate in the population is 8 0.180 = individuals per Drosophila per week.

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In the equation dN K NrNdt K −⎛⎞= ⎜⎟⎝⎠ , K represents carrying capacity. - 53 - NEET (UG)-2024 (Code-Q1)

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Gause's competitive exclusion principle states that two closely related species competing for the same resources cannot exist indefinitely and the competitively inferior one will be eliminated eventually. This may be true if resources are limiting.

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Ramdeo Misra is known as the father of Ecology in India. NCERT XII chapter Organisms and Populations highlights his contributions to the field of ecology in India, so option (b) is correct.

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Fig fruit is a vegetarian fruit as it only gets pollinated by wasp. Fig tree and fig wasps shows mutualism in which both species are benefitted. So, statement I is incorrect. Statement II is also not correct as fig inflorescence/flower gets pollinated by fig wasp.

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Azotobacter, Oscillatoria, and Anabaena are nitrogen-fixing organisms, while Volvox is a photosynthetic alga that does not fix nitrogen. NCERT XII chapter Organisms and Populations discusses nitrogen-fixing organisms, so option (d) is correct. However, the correct option provided is (a), which is incorrect based on the NCERT content. The correct answer should be (d) Volvox.

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The Verhulst-Pearl Logistic Growth equation is given by $\frac{dN}{dt}=rN\left(\frac{K-N}{K}\right)$, where $r$ is the intrinsic growth rate, $N$ is the population size, and $K$ is the carrying capacity. This equation describes how population growth slows as $N$ approaches $K$. Option (b) is correct.