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Mechanism of speciation

By-Anshika Bansal135019

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Modes of speciation• ALLOPATRIC SPECIATION

• REPRODUCTION ISOLATION

• PERIPATRIC SPECIATION

• SYMPATRIC SPECIATION(*) POLYPLOIDY

• PARAPATRIC SPECIATION

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Allopatric (allo=other, patric=place) Speciation

• speciation that occurs in geographically isolated populations

• separation due to different geographical events

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Reproductive isolation-

Two group of individuals evolved from same parental population do not interbreed.

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Post zygotic reproductive isolation

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Peripatric (peri=near, patric=place) Speciation

• a small subset of a large population becomes isolated at the periphery of the original population's range

• Over generations, the small group becomes reproductively isolated from the original population.

• THIS TYPE OF SPECIATION ALSO KNOWN AS FOUNDER EFFECT

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Parapatric (para=beside, patric=place) Speciation

• Individuals are more likely to mate with their geographic neighbors. This also results in a reduced gene flow within the population

• no specific barrier to gene flow

• the mating behavior is NOT random

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Example-

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Sympatric (sym=same, patric=place) Speciation

• a species splits into two groups that diversify and become genetically isolated while remaining in the same place.

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Example-

Polyploidy in plants

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Autopolyploidy (chromosomes in the new species all from the same ancestral species)

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Allopolyploidy (chromosomes in the new species come from two different (but related) ancestral species)

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CONCLUSION

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