In the past week or so we have covered a number of wide-ranging topics all of which are related.
Natural Selection
This is frequently known as “survival of the fittest”. This is summarised in the video below;
Examples that you should be able to explain include; the peppered moth, sickle cell trait and antiobiotic resistance.
Natural selection involve selection pressures such as disease, predation and lack of food. This results in animals which are best suited to their environment surviving and interbreeding. Those animals who survive and interbreed tend to show a mutation which is advantageous in one way or another.
Speciation
Speciation is the formation of a new species. The steps involved in the process are shown below;
There are also crash course videos available about speciation;
Adaptive Radiation
Adaptive radiation is when a group of organisms who have a common ancestor, evolve in a variety of directions to fill different ecological niches.
This definition is also true of divergent evolution. Examples of adaptive radiation include Darwin’s finches, marsupials and the British buttercup.
Convergent evolution is a little different. Here animals who do not have a common ancestor evolve over time to fill the same ecological niche. Examples include; European and Marsupial moles.
Extinction and Conservation
Mass extinctions tend to occur as a result of changes in the global climate. Humans also have had a part to play in causing extinction through over-hunting and habitat destruction.
Conservation can be achieved through a number of different mechanisms such as, captive breeding programmes, rare-breed farms, wild-life reserves and national parks as well as gene or cell banks.
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