Question

The main features of Darwin’s theory of evolution are
A.Struggle for existence
B.Natural selection
C.Survival of the fittest
D.All of the above

Answer 1

Evolution word was given by Spencer. Evolution is the process of origin of life and development of various living organisms from pre-existing organisms.
Charles Darwin presented the theory of evolution. He gave some concepts of the origin of life and evolution that provided a great contribution to understanding Evolution.

Complete answer: 1. Darwin presented the theory of natural selection. According to his concept to live various species struggle with each other. Because various organisms produce a huge population through reproduction.
2. So Darwin concluded that those organisms which are less suitable to survive in nature are replaced it means that they cannot remain alive.
3.But only those organisms remain alive which are suitable to live-in the environment.
4. It happens because some organisms are adapted to live in the changing environment while others are not. This adaptation means the development of some features that are suitable to live in some special environmental conditions.
5. Only those organisms can survive which are adapted to live in a changing environment, this is called survival of the fittest.
6. So nature only chooses those organisms which are suitable for the environment and this is called natural selection.
7. Darwin concluded that all the organisms that earlier lived on earth were developed slowly. Genetic variations were developed in living organisms that helped them to survive. These variations made them more fertile and these variations are inherited.
So, the correct option is D. All of the above.

Note: 1. We can understand the theory of natural selection by this example. In England around 1850 it was observed that before 1850 industrialization was not initiated, So the population of the white peppered moths (Bistan Bitularia typical) was more than dark peppered moths (Bistan Bitularia carbonaria). It was so because this white moth can hide from predators. The stems of trees were white at that time because of the presence of lichens so predators can not see the white moth.
2. But after industrialization around 1920 Dark-colored moths were more than a white peppered moth. It was so because a dark-colored moth can hide from predators but a white moth cannot. The stem of trees became dark due to pollution and predator cannot see the dark moths.
3. So only that moth could survive which was suitable according to the environment.