Genetics and Evolution

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  • Created by: jessica
  • Created on: 19-03-13 15:43
When is a new species defined?
when it can no longer mate with its former self.
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What can cause isolated populations to diverge?
Mutation, selection and genetic drift
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What is allopatric speciation?
This is when physical isolation is involved.Two populations undergo different selection pressures.
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What is sympatric speciation?
The populations are reproductively isolated but may not be physically isolated.
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What are pre-mating isolation mechanisms?
ecological, seasonal/temporal, sexual, mechanical, isolation by different populations
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What are post mating isolation mechanisms?
gametic isolation, hybrid unviability, hybrid sterility, hybrid breakdown.
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What are sibling species?
Reproductively isolated species that are difficult to distinguish by morphological characters
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What are sub-species?
Taxonomic term for populations of a species that are distinguishable by one or more characteristics - sometimes the term Form is also used.
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What is hybridization?
Interbreeding between genetically different populations resulting in offspring that are F1, F2 and backcross hybrids.
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What is introgression?
The movement, or incorporation, of genes from one genetically distinct population (species or sub-species) into another through introgressive hybridization
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What is a species?
group of organisms that can exchange genes among themselves but are genetically unable to exchange genes in nature with individuals in other such groups.
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What is a geographical race?
phenotypically distinguishable local population within a species that is capable of exchanging genes with other races within that species. e.g. Native Americans
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Give an example of prezygotic isolation
Pinus radiata and Pinus muricata, types of pine tree shed their pollen in February and April, so their pollen will not mix and exchange genes.
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Give an example of postzygotic isolation
failure of fertilized zygotes to contribute gametes to future generations. This is more common in animals than in plants. e.g. mule, zebroid
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Card 2

Front

What can cause isolated populations to diverge?

Back

Mutation, selection and genetic drift

Card 3

Front

What is allopatric speciation?

Back

Preview of the front of card 3

Card 4

Front

What is sympatric speciation?

Back

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Card 5

Front

What are pre-mating isolation mechanisms?

Back

Preview of the front of card 5
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