Question

Mention any two examples of evolution by anthropogenic action?

Answer 1

Hint: Evolution refers to the process of gradual alterations seen in consecutive generations arising from one species. Evolution also results in the formation of new individual species from existing ones due to major physiological changes. Anthropogenic action means activities performed by humans that cause pollution or changes in environmental aspects.

Complete answer:Evolution is a process of gradual variation induced to a particular species that is caused by natural selection or genetic drift. The variations are heritable and thus lead to specific phenotypic characters in a specific group of species causing them to become different. This leads to the emergence of a new group representing a new species.
Anthropogenic activities are all those activities that involve human actions causing pollution. These activities include smoke from factories or industrial pollution. The anthropogenic activities lead to certain environmental alterations that stimulate the species living in that area to get mutated. The mutations cause variations that are inherited over time leading to the disappearance of initial species.
The two main types of evolution caused by anthropogenic activities are:
1.Industrial melanism- Melanism refers to the development of excess melanin pigment that gives dark or black color to skin or hair. Industrial wastes and exhausts are sources of very strong pollutants like sulfur dioxide gas and dark soot. The trees around industries are usually covered by lichens. The sulfur dioxide gas kills lichens and the bare barks of trees get darker by deposition of soot. This causes the inhabitants of that area to undergo mutations. This can be seen in Lepidoptera species. These organisms include butterflies and moths that become darker due to melanin deposition. Natural selection allows them to have better camouflage on darker trees.
2.Overuse of weedicides and pesticides by humans in fields also results in evolution. Many weeds and insects become resistant to these chemicals. This results in mutation and then evolution.

Note: Anthropogenic activities are a real issue to be addressed as they lead to the degradation of the natural ecosystem. Excess use of harmful chemicals may lead to many resistant pests that will not be affected by any pesticides. Also, in bacteria, antibiotic resistance can be seen. This is due to the overuse of antibiotics.