Speciation

Created by: Emily250601
Created on: 09-06-19 17:33

What is speciation?

The development of a new species - occurs when populations of the same species become reproductively isolated- changes in allele frequencies cause changes in phenotypes that mean they can no longer breed together to produce fertile offspring

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What is geographical isolation?

When a physical barrier divides a population of a species e.g. floods, volcanic eruptions and earthquakes. - conditions on either side of the barrier are slightly different so natural selection occurs (due to different selection pressures)

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How does geographical isolation lead to speciation?

1.Different characteristics will be advantageous on each side, the allele frequencies will change in each population. 2.Mutations take place in each population, changing allele frequencies 3.Allele frequency changes= eventual reproductive isolation

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How does reproductive isolation occur?

1. seasonal changes-individuals from same population develop different mating seasons. 2. Mechanical changes- changes in genitalia prevent successful mating 3.Behavioural changes-group of individuals develop courtship rituals= not attractive to main

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What is speciation without geographical isolation called?

Sympatric speciation- due to random mutations that lead to seasonal changes, mechanical changes or behavioural changes

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Other cards in this set

Card 2

Front

What is geographical isolation?

Back

Card 3

Front

How does geographical isolation lead to speciation?

Back

Card 4

Front

How does reproductive isolation occur?

Back

Card 5

Front

What is speciation without geographical isolation called?

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Speciation