Zoology MCQs for NEET — Practice Questions with Answers

Macro evolutionary processes are large-scale evolutionary changes that occur over long periods of geological time and result in the formation of new species or other taxonomic groups. Option o4 describes a change in gene frequency over a short period of time, which is an example of microevolution, not macroevolution.

Microevolution refers to small-scale changes within a species, such as changes in allele frequencies. The extinction of a species, as mentioned in option o4, is a macroevolutionary event because it involves the disappearance of an entire species rather than changes within a species.

Natural selection generally favors traits that provide some adaptive advantage. Traits that appear to have no adaptive value, as mentioned in option o4, are difficult to explain in terms of natural selection because they do not seem to offer any benefit for survival or reproduction.

A monophyletic taxon includes all the descendants of a common ancestor. The first fish species and every living organism that looks like a fish do not form a monophyletic group because it might exclude some descendants that do not look like a fish. In contrast, the first mammal species and all its descendants, as well as the first bird species and all its descendants, form monophyletic groups as they include all the descendants.

The correct answer is a combination of points 1 and 2. Organisms that look alike may be very distantly related to one another due to convergent evolution, where unrelated species independently evolve similar traits. Also, similarities between two species may be due to common descent without indicating how closely the two are related. This makes relying solely on similarity potentially misleading when inferring evolutionary relationships.

The correct answer is that some members of the ancestral population had larger beaks than others, and if larger beak size was advantageous, those individuals would be more likely to survive and reproduce. This explanation aligns with the concept of natural selection, where advantageous traits become more common in a population over time.

In an evolutionary sense, 'fitness' is defined by the ability to survive and reproduce. A lion who has many cubs, eight of which live to adulthood, has demonstrated higher fitness because it has successfully passed on its genes to a larger number of offspring who have also survived to reproduce.

FACT

To determine the ancestral state of a characteristic within a group of closely related species, it is useful to refer to an outgroup (a more distantly related species). By examining whether the outgroup has the characteristic in question (forked tongue in this case), the biologist can infer whether the characteristic is ancestral or derived. If the outgroup has the characteristic, it is more likely to be ancestral.