Answer to Question #113827 in Evolution for NIBEDITA RUDRA

Question

Briefly explain the tenents of Darwin's 5
theory. Why has Darwin's original theory
undergone modifications ?

Answer 1

1)There are five main tenets of Darwin's theory of evolution:

1. Each generation generates more offspring than can be supported by the environment. Environmental resources for things such as food and shelter are limited.
2. There are differences within each generation which is referred to as phenotypic variation or traits.
3. Phenotypic variation exists among individuals and the variation is heritable.
4. When reproductive isolation occurs new species will form.
5. Populations tend to remain stable in size, except for seasonal changes .

2) Basically, Darwin’s original theory undergone modifications due to development of genetic analysis methods.Studies in genetics and molecular biology were unknown in Darwin's time and explain the occurrence of the hereditary variations that are essential to natural selection. Genetic variations result from changes, or mutations, in the nucleotide sequence of DNA, the molecule that genes are made from. Such changes in DNA now can be detected and described with great precision.