Glossary

Allopatric

Where a population or species occupies a different geographic region to another population or species. See also sympatric and parapatric.

Allopatric speciation

Where different populations are formed, without intermediates, if physical barriers restrict gene flow. There are two types: vicariant speciation and peripatric speciation....More

Allopolyploidy

Chromosomes donated from >1 parental species. See also polyploidy and autopolyploidy.

Autopolyploidy

Chromosomes donated from one parental species. See also polyploidy and allopolyploidy.

Frequency-dependent selection

Selection of a genotype depending on its frequency in the population, e.g. scale eating fish. See resource polymorphism.

Hybrid

An individual resulting from mating between genetically distinct populations/species. See also hybrid zone.

Hybrid zone

A region in which genetically distinct populations come into contact and produce offspring off mixed ancestry. This process is known as hybridisation.

Hybridisation

See hybrid zone and hybrid. If new species are formed by hybridisation the hybrids must have higher fitness than the parental forms, they can achieve this by occupying new niches.

Isolating mechanism

A genetic difference between populations that prevents or restricts gene flow between them. See reproductive isolation.

Parallel evolution

The evolution of similar or identical characters independently in related lineages.

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