Question

Explain Darwin’s theory of natural selection with industrial melanism as an experimental proof.

Answer 1

He observed that the characteristics of many plants and animals vary greatly among the island. He studied tortoises and marine iguanas in the Galapagos islands. He observed that each island supported its form of finch which was closely related but different in important ways.

Complete answer:
-The process of inheriting their characters which are well suited for the environment they live in and helps in reproduction to produce more offspring than average is called natural selection.
Industrial melanism is a developmental process which is crucial for arthropods, where dark colour is observed in an ecosystem which is affected by industrial pollution, mainly sulphur dioxide gas as well as dark ash deposits.
-Industrial melanin was an experimental observation based on the proportional increase of dark or melanin this pigment present in the individuals of populations causes change in the environment that result in the industrial pollution.
-Industrial melanism tells about the cause of industrial pollution in the moth population.
-Before industrialization, the number of the white colored moths on a tree were more than dark colored moths. The less pigmented lichen used to grow on trees and therefore moth predators could not spot white moths easily so dark moths were lesser in population. But because of industrial pollution, lichen could not develop on trees and then it became tough to recognize dense moths on the dense background of stem and hence white moths were very less than dark moths. This process is termed as industrial melanism.
-So before industrialization, white moths were best inclined to nature but when but after industrialization occurred, dark coloured moths were mainly fitted for the changing environmental conditions. This assisted Darwin’s theory of natural selection as the natural condition changes, the organism which is more fit for the environment survives better than the other.

Note: According to Darwin’s theory:
-Each organism is different with pros and cons in the struggle of existence.
-The individuals which are best suited for the environment survive and reproduce most successfully.
-Species change over time.
-Species alive today descended with modification or evolution from species that lived in the past.
-All organisms present on earth are united into a single family tree of life by common descent.