Hybridization Leads to Speciation

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Hybridization Leads to Speciation:

Hybridization Leads to Speciation Aditya Rai Biology 7


Speciation - Process by which new species arises from another species. -Has been a major part of evolutionary biology. -Modes of Speciation: A) Allopatric B) Peripatric C) Parapatric D) Sympatric



Allopatric Speciation:

Allopatric Speciation - Speciataition by geographic isolation.

Peripatric Speciation:

Peripatric Speciation -A subform of allopatric speciation. -New species are formed in isolated, smaller peripheral populations that are prevented from exchanging genes with the main population. -Isolated indivduals decrease in size causing a small population size. -Genetic drift acts faster in small populations. -Genetic drift can lead to speciation.

Parapatric Speciation:

Parapatric Speciation - Continuous growth of population. -No random mating. -Individuals are likely to mate with geographic neighbors, due to certain pressures, which can lead to speciation. As the species mate with their geographic neighbors they will change from the parent species and thus speciation has occurred.

Sympatric Speciation :

Sympatric Speciation -A species arises from another species from the same environment. -The species inhabits a new niche and adpating to that new niche develops certain characteristics making it a new species. -This is different from allopatric speciation because it happens in the same environment.

Hybrid Speciation:

Hybrid Speciation -Two closely related species breed and make a new species that is reproductively isolated from the parent species. -Fairly common in plants. -From the 1940s it was difficult to isolate the reproductive genes from offspring and parents so hybridization seemed very rare. -In the 1990s when reproductive isolation was more advanced hybridization was found to be a very common phenomenon. (Especially in plants)

Introgression or Introgressive Hybridization:

Introgression or Introgressive Hybridization -Movement of genes from one species to the other by the means of backcrossing hybrid with its parent. -Has major effects in the sympatric mode. -A much more complex process than simple hybridization.

Heliconius Butterfly data :

Heliconius Butterfly data 5/7/13

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