Isolation and the Evolution of New Species and Extinction.

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Isolation and the Evolution of New Species and
Extinction.
Geographical Isolation: When two populations become
physically isolated from one another by a geological feature. E.g.
A mountain Range.
Environmental Isolation: When the climate changed in one area
where an organism lived but not in the others. E.g. Climate
becomes warmer in one part where plants are, so will flower at
different times of the year.
Endemic Organisms: This happens when a species has formed in
isolation and so they are only found in one place in the world.
The organisms are said to be endemic to that area.
Extinction: The permanent loss of all the members of a species.
New diseases, new successful competitors or new predators.
Mass Extinction: The extinction of many species.
Fossils: Remains of organisms from thousands or millions of
years ago that are found preserved in rocks, ice and other places.
Specification:
When a species is separated by isolation, each population will
still contain genetic variation, due to mutation and sexual
reproduction. It is the best alleles controlling different
characteristics ­ both genotypes and phenotypes ­ that are
passed on through evolution for offspring to survive and breed
successfully this is known as natural selection.
However sometimes a species can be isolated and split, so there
are different populations of the same species in different
environments. The populations evolve to survive best in their own
environments and so their characteristics from their alleles
become very different. As a result of this the different populations
then become so different that they can no longer interbreed

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This is known as
specification.…read more

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