Question

*For 10th grade*
Q. Explain the evidences responsible for evolution

Answer 1

Evolution is a slow change in inherited characters of a population over a long period of time. The evolution may occur due to genetic variation, natural selection, adaptation, geographical changes and many more.

Evidences of Evolution

• Fossils− They represent plants and animals that lived millions of years ago and are now extinct. Different aged rock sediments contain fossils of different life-forms, which probably died during the formation of the particular sediment.
• Comparative anatomy and morphology− It shows evidences of the similarities and differences between living forms of today and that of the prehistoric times. Some of the examples of comparative anatomy and morphology are:

• Homologous organs− All mammals share the same pattern of forelimbs. Though they perform different functions, they are anatomically similar. This is calleddivergent evolutionand the structures are called homologous structures (common ancestors).
• Analogous organs− The pair of organs is not anatomically similar, but performs the same function (e.g., the wings of butterflies and birds). This is calledconvergent evolution.

• Adaptive melanism− In England, it was noted that before industrial revolution, the number of white-winged moths was more than that of dark melanised moth. However, after industrialisation, there were more of dark melanised moths. The explanation was that after industrialization, the tree trunks became darker with deposits of soot and smoke and hence, the number of dark moths increased in order to protect themselves from predators while the white-winged ones were easily picked up by the predators.
• Similarly, the herbicide and pesticide resistant plants and animals and antibiotic resistant bacteria are some of the evidences that point towards evolution