Question

Give the salient features of the following:

Darwinism

Answer 1

1. Rapid Multiplication (Overproduction): Every organism has the ability to produce a very large number of offspring. Organisms multiply in a geometric ratio. For example, an organism may double in number in the first year, become four times in the second year and eight times in the third year, and so on. Plants produce thousands of seeds, while insects lay hundreds of eggs. A cod-fish lays several hundred eggs at a time. One pair of elephants produces about six offspring, and if all of them survived and continued multiplying at the same rate, their number would become very large after some time.
2. Struggle for Existence: Although all species multiply rapidly, food, space and other resources are limited. Every individual competes with other individuals of the same or different species for basic necessities. This is called the struggle for existence. The struggle can be of three types: 
   1. Intraspecific struggle: Competition between individuals of the same species. For example, two dogs may fight for a piece of meat. War is another example of intraspecific struggle among different human communities.
   2. Interspecific struggle: Competition between individuals of different species. For example, a tiger attacks a deer for food. 
   3. Environmental struggle: Every individual struggles against changes in environmental conditions such as temperature, humidity, water level, rainfall and climate.
3. Appearance of Variation: Every individual differs from other individuals in several aspects. Even offspring produced by the same parents differ from each other in many ways. Individuals may differ in behaviour, colour, size, strength, etc. According to Darwin, variations are continuous. Variations that help an organism adapt to its surroundings are passed on to the next generation, while other variations disappear.
4. Survival of the Fittest or Natural Selection: In the struggle for existence, only those individuals survive which possess useful variations. This means that nature selects the fit individuals. This process is called natural selection. According to Darwin, the most suitable and fit individuals succeed in the struggle for existence. The original idea of “survival of the fittest” was given by Herbert Spencer.
5. Origin of New Species: Darwin explained that variations arising due to environmental changes are transmitted to the next generation. Therefore, offspring become different from their ancestors. In the next generation, the process of natural selection is repeated. Thus, after many generations, a new species is formed.