Speciation
Speciation is a process within evolution that leads to the formation of new, distinct species that are reproductively isolated from one another.
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It involves the splitting of a single evolutionary lineage into two or more genetically independent lineages.
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New species form by two major mechanisms namely, sympatric speciation and allopatric speciation.
1. ALLOPATRIC SPECIATION
- The physical isolation of the biology population due to the extrinsic barrier is called allopatric speciation.
- Allopatric speciation occurs when a population of organisms becomes separated or isolated from their main group due to geographical barriers.
- Over time, the new groups consisting of homogenous individuals become subjective to changes via natural selection due to pressure from differences in predators, climate, competitors and resources. Populations can become isolated for a variety of reasons.
2. SYMPATRIC SPECIATION
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The evolution of new species from one ancestral species by living in the same habitat is called sympatric speciation.
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This type of speciation happens in a population without geographic isolation.
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The main mechanisms resulting in sympatric speciation involve changes in the chromosomes of the organism. One way this happens is when there is a serious error that occurs during cell division resulting in more than one copy of a chromosome(s), or the loss of a chromosome(s), in one of the daughter cells. This condition is known as aneuploidy.