Variation

 

Variation refers to the differences in characteristics between individuals of the same species. You can also refer to variation between different species.

 

Variation can be due to differences in the following 3 things:

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There is a lot of genetic variation between populations in a species, e.g. humans, and It is important to note that all of this variation comes from mutations.

 

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Evolution (see more in 6.2.1)

 

Evolution is the change in the inherited characteristics of biological populations over time through natural selection. 

 

The process of evolution may result in the formation of a new species 

 

How does natural selection work?

1. Variation in population  

2. Selection pressure in the environment (cold, predators, food)  

3. Best adapted survive, less adapted die

4. The best adapted then reproduce and pass on alleles to their offspring

5. This repeats and the allele frequency increases over generations

 

A selection pressure is a factor of an environment that influences the reproductive success of an organism e.g. cold weather means only better adapted organisms can survive and reproduce

 

Darwin created the theory of evolution by natural selection which states that “all living organisms have developed from simpler life forms over billions of years”

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If two populations of the same species evolve independently of each other for a long time, they may no longer be able to reproduce to produce fertile offspring. At this point, a new species has been formed.