Question

Evolution in a population occurring over long periods of time as a result of the accumulation of small changes is referred to

• A. Punctuated equilibrium
• B. Adeptive rediation
• C. Allopatric speciation
• D. Gradualism
• E. Convergent evolution

Answer 1

The correct option is D Gradualism

A. Punctuated equilibrium is a evolutionary theory which states that population becomes stable once a species appears and it shows a little evolutionary change in its geological history.

B. Adaptive radiation is a special evolutionary pattern characterised by rapid increase in the numbers of kinds of closely related species. It results in an evolutionary explosion of new species from a common ancestor. For example, Darwin's finches.

C. Changing climate may isolate population on mountain peaks or in remnant lakes, or rare migrants may colonise new areas such as the Galapagos and Hawaiian islands. This geographic isolation is termed as allopatry and gives rise to allopatric speciation.

D. Gradualism is a evolutionary model which states that there is transformation of one species into a new species and in this way, evolution occurs uniformly, slowly and gradually over long period of times.

E. Convergent evolution is a process during which organisms with different evolutionary history evolve similar phenotypic adaptations in response to common environmental conditions. Hence, analogous organs are formed which have different basic structure but perform similar functions. For example, insect wings and birds wings.

Hence, evolution in a population occurring over long periods of time as a result of the accumulation of small changes is referred to as Gradualism.

So, the correct answer is 'Gradualism'.