Darwin’s Theory of Natural Selection (Darwinism)

Differences between individuals of the same species that arise naturally and can be passed to offspring are called variations.

The modern version of Darwin’s theory of natural selection, which incorporates genetics as the source of variations, is called Neo-Darwinism.

1. Darwinism - Proposed by Charles Darwin after extensive travels; published in the book "On the Origin of Species by Means of Natural Selection"; the essence of the theory is natural selection.

2. Galapagos Islands - Darwin observed variations in tortoises and finches across the islands of the Archipelago, which became key evidence for his theory.

3. Natural Selection - Nature selects only those organisms that are fit to survive; the rest perish — this is the concept of "Survival of the Fittest".

4. Competition & Modification - All organisms reproduce prolifically and compete for survival; only those with useful modifications win the competition and sustain.

5. Evidences for Darwinism -

• Long-necked Giraffe - Giraffes developed long necks to reach leaves; this adaptation became fixed and was passed to offspring.
• Black Peppered Moths - Gradually became more common due to industrial melanism.
• DDT Resistance in Mosquitoes - Some mosquitoes developed resistance to DDT, survived, and produced resistant offspring.