Question

Explain evolution by natural selection?

Answer 1

1. Natural selection is the process through which organisms that are better adapted to their environment survive and produce more offspring.
2. Natural selection may result in the formation of a new type of organism over many generations.
3. This gradual process by which a new type of organism evolves from an older form is called evolution.
4. During a five-year voyage on the ship HMS Beagle, Charles Darwin, an English naturalist, observed variety in plants, animals, and fossils.
5. He explained, Natural selection guarantees that only organisms with qualities best adapted to their environment survive and reproduce effectively, passing on their characteristics to their children. He named this process as “survival of fittest”.
6. He also discussed how new species emerge as a result of natural selection.
7. Darwin discovered a species of finch on the Galapagos Islands, which is a famous illustration of natural selection.
8. He discovered that the sizes and forms of the birds' beaks differed from island to island.
9. He realised that each finch's different beaks assisted the birds in acquiring a certain type of food.
10. Seed-eating finches, For example, had thicker, longer beaks for breaking seeds, but insect-eating finches developed spear-like beaks for stabbing their food.
11. As a result, Darwin proposed that numerous species with minor differences arose by natural selection from a common ancestor.

The following are the main points of the theory of evolution through natural selection.

1. Individuals in a species exhibit a wide range of variety, which is caused by both genes and the environment, but only genetic variation can be passed down to the next generations.
2. Individuals with special adaptations in their environment have a better chance of surviving and reproducing.
3. When competing against better-adapted individuals, individuals who are poorly adapted have a lower chance of surviving and reproducing.