Question

According to Darwin, diversity as found in Australian marsupials is due to:
A. Convergent evolution
B. Adaptive radiation
C. Parallel radiation
D. Parallel evolution

Answer 1

Hint: Diversity of life is defined as the variety of life forms found on earth. It has been changing over millions of years and at present, includes microorganisms, plants, animals, and the whole ecosystem. Diversity is increased by genetic variations.

Complete answer:
Australian marsupials include a number of marsupials that are different from each other but have evolved from an ancestral stock within the Australian island continent. The placental mammals of Australia show diversity in such a manner that each placental mammal looks very similar to a corresponding marsupial. They exhibit the same ecological niche but are present in different parts of the world as a result of continental drift. Such an evolution is considered to be called convergent evolution.
Convergent evolution means that the animals that are not closely related to each other but belonging to the same ecosystem or having similar lifestyles get evolved in such a way that they show similar physical characteristic traits. The organisms show similar characters due to a similar environment. If we take an example of Australian marsupials, the placental wolf and the Tasmanian wolf look quite similar in appearance. Thus, placental mammals found in Australia appear much like their corresponding marsupial due to convergent evolution.
So, the correct answer is “Option A”.

Note: Adaptive radiation is the process of evolution of organisms from an ancestor in such a way as to modify according to their changing environment.
Parallel radiation is defined as the similarity among two species for any particular character that occurred due to environmental changes when their ancestors were also similar.
Parallel evolution is the formation of similar traits in species that have the same ancestor but are distinct from each other.