Evolution MCQs for NEET — Zoology Questions with Answers

The text states, 'Another example is Australian marsupials. A number of marsupials, each different from the other (Figure 6.6) evolved from an ancestral stock, but all within the Australian island continent.'

The NCERT text mentions, 'When more than one adaptive radiation appeared to have occurred in an isolated geographical area (representing different habitats), one can call this convergent evolution. Placental mammals in Australia also exhibit adaptive radiation in evolving into varieties of such placental mammals each of which appears to be ‘similar’ to a corresponding marsupial.'

The text states, 'Placental mammals in Australia also exhibit adaptive radiation in evolving into varieties of such placental mammals each of which appears to be ‘similar’ to a corresponding marsupial (e.g., Placental wolf and Tasmanian wolf-marsupial).' This similarity between distantly related groups in similar niches is convergent evolution, which is seen in conjunction with adaptive radiation within each group.

The text states, 'There he observed an amazing diversity of creatures. Of particular interest, small black birds later called Darwin’s Finches amazed him. He realised that there were many varieties of finches in the same island. All the varieties, he conjectured, evolved on the island itself. From the original seed-eating features, many other forms with altered beaks arose, enabling them to become insectivorous and vegetarian finches.'

Adaptive radiation involves diversification into different habitats (ecological niches). An isolated geographical area with available, varied niches allows for less competition and more opportunities for a single ancestral stock to diversify and adapt.

Adaptive radiation implies diversification into numerous distinct forms occupying varied ecological niches from a single ancestral stock in an isolated geographical area. While humans have adapted to diverse environments, human evolution is generally considered a more linear or branching evolution within the Homo genus, rather than a broad 'radiation' into many distinct, niche-specific 'species' from a single recent ancestor in an isolated region in the same way as Darwin's finches or marsupials.

The text explicitly mentions, 'Placental mammals in Australia also exhibit adaptive radiation in evolving into varieties of such placental mammals each of which appears to be ‘similar’ to a corresponding marsupial (e.g., Placental wolf and Tasmanian wolf-marsupial).' This similarity between two distinct evolutionary lineages adapting to similar ecological roles is a classic example of convergent evolution.

Five factors known to affect Hardy-Weinberg equilibrium are gene migration (gene flow), genetic drift, mutation, genetic recombination, and natural selection. Random mating is a condition for the equilibrium to hold, not a factor that disturbs it.

The sum total of all allelic frequencies is 1. If $p$ represents the frequency of allele A and $q$ represents the frequency of allele a, then $p+q=1$. Given $p=0.7$, then $q = 1 - 0.7 = 0.3$.

The text states, 'Sometimes the change in allele frequency is so different in the new sample of population that they become a different species. The original drifted population becomes founders and the effect is called founder effect.' This directly links the founder effect to genetic drift.