Tag: other theories of evolution

Thomas Malthus' opinions regarding the struggle to survive helped to inspire Charles Darwin in his development of the theory of natural selection. Darwin noted that the population-food imbalance postulated by Malthus would lead to competition between offspring. He considered that some of those offspring would be better equipped for the struggle than others, and so would flourish. This "survival of the fittest" became the central theme to Darwin's developing theory. 

The modern synthetic theory of evolution is the result of the work of a number of scientists namely T. Dobzhansky, R.A. Fisher, J.B.S. Haldane, Swall Wright, Ernst Mayr, and G.L. Stebbins. Stebbins in his book, Process of Organic Evolution, discussed the synthetic theory.
It includes the following factors 

Environmental change and isolation of groups of organisms play an important role in evolution. Isolation means that organisms of the same species are separated, and happens when there is something between the organisms that they can't cross. Organisms become isolated as a result of environmental change. The cause of isolation can be gradual, like when mountains or deserts form, or continents split apart. It can also be quick, such as organisms being blown to different places by a storm or tsunami (tidal waves).
When organisms become isolated the two groups are also not able to reproduce together, so variations and mutations that occur in one group are not necessarily found in the other group. The longer the groups are isolated, the more different they are. They eventually become different species. Moreover, if there is a change in the environment of one group it does not necessarily occur in the environment of the other. So they will evolve and adapt differently. So, the role of isolation in evolution is maintenance of species. Thus, option B is correct.
Differentiation of species or evolutionary divergence or extermination of species are not the roles of isolation in evolution. Thus, other options are wrong.

Darwin, in the fourth edition of his 'On the Origin of Species', wrote that the first author who in modern times has treated in a scientific spirit was Buffon a significant reference from the man known as the father of evolutionary theory. Buffon was known to have changed his views often during the course of his life and this is possibly why he is rarely referred to in the history of evolutionary thought. However, he is lauded by modern evolutionists as having posed significant questions about the development of life on Earth. Therefore, the correct answer is option B.