Question

Inclusive fitness theory is proposed by
A. Darwin
B. Lamarck
C. Weismann
D. Hamilton

Answer 1

Hint: The study of the history of life forms like changes in flora and fauna that have occurred over millions of years on earth is known as evolution. Evolution is an orderly change from one condition to another. Several theories are proposed to explain the real concept and reason for the origin of life and evolution namely- theory of special creation, the theory of spontaneous generation, the theory of biogenesis, and many more. Among all these theories, the theory of natural selection is the most accepted theory of evolution.

Complete answer:
The first logical theory of evolution was proposed by a French naturalist Lamarck. He proposed the theory of inheritance of acquired characters.
After the Darwinian theory of natural selection, neo Darwinism, or the modern synthetic theory of organic evolution is being proposed by Weismann and other scientists.
Darwin's theory of natural selection states that individuals with more adaptive variations are a better fit than individuals with less adaptive variations. Hence those who are a better fit in an environment would be selected by nature and leave more progeny than others. The result of the ability to adapt and get selected by nature is fitness. The fitness of an organism ultimately refers to reproductive fitness. The variations occurring during evolution ultimately result in the production of superior progenies. This is called the organism's genetic success.
Altruism is a behavior of an organism that leads to the benefit of another organism at some cost. This altruistic behavior of organisms is explained in the theory called Inclusive fitness theory proposed by Hamilton. According to this theory if a gene that is being passed is altruistic then it increases the survival of the organism of the next generation. It increases the superiority of a particular gene and the progenies being produced will be more superior to others.
An increase in the evolutionary success of a gene by promoting the survival of the individual carrying that particular gene is called an Inclusive theory of fitness.

Thus the correct answer is option (D).

Note:
Sexually reproducing organisms produce new combinations of genes which are the continuous and common source of variations seen. If gene migration from one population to another takes place continuously then it will ultimately lead to gene flow of that particular gene. The overall fitness of an organism includes both Darwinian fitness and inclusive fitness. Thus the inclusive fitness theory is closely related to the theory of natural selection.