Botany MCQs for NEET — Practice Questions with Answers

The NCERT text specifies: 'According to the International Union for Conservation of Nature and Natural Resources (IUCN) (2004), the total number of plant and animal species described so far is slightly more than 1.5 million.'

The NCERT text states: 'If we accept May’s global estimates, only 22 per cent of the total species have been recorded so far. Applying this proportion to India’s diversity figures, we estimate that there are probably more than 1,00,000 plant species and more than 3,00,000 animal species yet to be discovered and described.'

The NCERT text explicitly mentions: 'The diversity at the species level, for example, the Western Ghats have a greater amphibian species diversity than the Eastern Ghats.'

Genetic diversity refers to the variations at the genetic level within a species. The example of Rauwolfia vomitoria directly illustrates this by highlighting differences in the 'potency and concentration of the active chemical (reserpine)' across its distributional range, which are genetically determined traits.

As per the NCERT text: I. 'India has more than 50,000 genetically different strains of rice' is an example of Genetic diversity. II. 'The Western Ghats have a greater amphibian species diversity than the Eastern Ghats' is an example of Species diversity. III. 'India, for instance, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity' is an example of Ecological diversity. Therefore, the order I, II, III correctly represents Genetic, Species, and Ecological diversity respectively.

Ecological diversity is not limited to a single ecosystem but refers to the diversity at the ecosystem level across a larger geographical region, as exemplified by India's vast array of diverse ecosystems (deserts, rainforests, etc.), implying a broader scope than a single ecosystem. The NCERT states 'At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity...'

The NCERT text states: 'Although India has only 2.4 per cent of the world’s land area, its share of the global species diversity is an impressive 8.1 per cent. That is what makes our country one of the 12 mega diversity countries of the world.' This highlights that being a mega-diversity country is due to having a disproportionately high species diversity relative to its land area.

The NCERT text explicitly states regarding latitudinal gradients: 'In general, species diversity decreases as we move away from the equator towards the poles.'

The NCERT text states: 'In addition to recombination, mutation is another phenomenon that leads to variation in DNA.' This directly identifies mutation as a source of variation.

The NCERT text mentions: 'Chromosomal aberrations are commonly observed in cancer cells.' This highlights the association between chromosomal alterations and cancer.