What is meant by the term ‘speciation’? List four factors which could lead to speciation

What is meant by the term ‘speciation’? List four factors which could lead to speciation.

Speciation: It refers “to the process by which new species develop from the existing species”.
Four Important factors which could lead to the formation of new species:

  1. Genetic drift: It caused by drastic changes in the frequencies of particular genes by chance alone.
  2. Geographical isolation of a population: This is caused by various types of barriers, example mountain ranges, river. Geographical isolation leads to reproductive isolation due to which there is no flow of genes between separated groups of population.
  3. Variation: They are caused in individuals due to natural selection process of Darwin.
  4. Sometimes a sub-population becomes reproductively isolated by ecological barriers: It takes place within same geographical area and within original populations.