Question

What is speciation? Describe in brief the factors that control the process of speciation.

Answer 1

Speciation is an evolutionary process by which new species arise. When new species arise, evolution is said to occur. Inheritable variations are the cause as they keep on accumulating from one generation to others and, ultimately, give rise to new species.

Complete answer: Speciation is the process of the formation of one or more new species from an existing species. The crucial phase in the origin of species occurs when the gene pool of a population is served from other populations of the parent species and gene flow no longer occurs.
On the geographical relationship, speciation can take place in two modes from new species to its ancestral species.
When the population splits into two or more geographically isolated populations and forms new species, the mode of speciation is called allopatric speciation. This can happen by subdivision of the original population, when a geographical barrier, such as a creeping glacier, a land bridge or ocean or mountains, cut across a species range
In the second speciation mode, a subpopulation becomes reproductively isolated amid its parent population; this is sympatric speciation. So, without geographical isolation, the formation of species within a single population occurs and is termed as sympatric speciation. Sympatric speciation is the result of polyploidy, which is the multiplication of the normal chromosome number. This can happen when chromosomes replicate without undergoing mitosis or fail to segregate at meiosis.

Note: Sibling species are those distinct species which are those distinct species which are almost identical morphologically but are distinct from each other due to the absence of interbreeding. The biological species concept is based on the absence of cross-fertilization between members of two species.