According to the idea of evolution in biology, the many species of plants, animals, and other living things on Earth descended from earlier species, and their recognisable differences are the result of changes made by subsequent generations.
Evolution is governed by four principles: variation, inheritance, selection, and time.
These are regarded as the elements of natural selection's evolutionary mechanism.
WhyEvolution important
Understanding the principles regulating the genesis and extinction of species is made possible by evolutionary biology.
It offers causal justifications for the complete spectrum of biological phenomena, from the molecular to the ecological, based on history and on processes of genetic change and adaptation.