A population accepts those traits which are helpful for the survival of that specific population. Whenever a new trait gets introduced in a population which can help them increase their number, they try to adapt to that particular trait.

There are four ways in which this can do. These are:-

(i) Natural selection: Natural selection may work differently in different location. Due to this, variations may occur which lead to the formation of a new species.

(ii) Geographical isolation: is the isolation of population by physical barriers such as stretches of water, mountain, etc.

(iii) Dna changes: variations during DNA copying often leads to the formation of a new species

(iv) genetic drift: Over generations, genetic drift may lead to the accumulation of different changes which leads to the formation of a new species.