Question

Industrial Melanism is an example of
(a) Natural selection
(b) Neo Lamarckism
(c) Neo Darwinism
(d) Mutation

Answer 1

Hint: Industrial Melanism is the development of dark coloration in populations that are exposed to industrial air pollution. This dark color is not dirt, but a genetically based increase in the concentration of melanin. Usually, it is produced by a dominant gene mutation. It involves protective and adaptive coloration in relation to the changing environment.

Complete step by step answer:
Industrial Melanism is a typical case of natural selection. It involves protective and adaptive coloration. A best example of this is shown by the peppered moth. These moths usually rest on the bark of the trees. There are two varieties of it namely; grey colored betularia form and dark- colored carbonaria form. In England, until the mid- 19th- century grey colored moths were abundant and dark- colored were very rare. Till that time tree trunks were covered with white lichen. So grey moths could easily blend with the background. But dark moths were at a definite disadvantage since predatory birds could easily spot them out. The air pollution that came with the Industrial Revolution killed lichens and covered the tree trunk with soot. Now, the grey moth fell easy to predator birds, since birds could easily detect them. At the same time, carbonaria form had the advantage of protection. So, their number increased tremendously. Again the use of oil and electricity in Industrial plants reversed this trend. As a result, the betularia forms became disproportionately numerous. This clearly shows that when environmental changes occur, nature selects and preserved the fittest or the most favorably adapted organisms.

So, the correct answer is 'Natural selection'.

Additional Information:
- Neo- Lamarckism is a modified and extended version of Lamarckism. It essentially holds that genetic changes may be influenced and directed by environmental factors and, to some extent, certain acquired characters are heritable.
- Neo Darwinism is the current theory that considers organic evolution as a change in gene frequency due to random mutation, with natural selection serving as the most important cause for such change.
- Mutation theory is that the evolution of new species is not a continuous process, but the result of sudden, discrete, and discontinuous change in existing species.

Note:
- The organisms which survive the struggle for existence transmit their heritable variations to the next generation.
- In this process, nature selects and preserves the favorable variations and rejects unfavorable or harmful ones.
- Darwinian theory of natural selection holds three cardinal aspects;
1) Nature preserve small useful and heritable variations,
2) Accumulation of useful variations over many generations leads to the origin of new species from existing ones.,
3) All complex organisms of the present and the past are the products of evolution from simple ancestors.