3.26 describe the process of evolution by means of natural selection

3.26 •theory of evolution: life began as simple organisms where complex ones evolved 

        •natural selection - the survival of the fittest 

        •individuals must compete to survive for these resources

        •some varieties of a particular species have a better chance of survival, thus increasing their chances of breeding and passing on their genes 

        •this means a greater proportion of the next generation will have these better alleles 

        •this happens over many generations and become better survivors - these ‘best features’ are naturally selected, allowing the species to be better adapted to the environment 

        •the best genes for a particular environment tend to survive 

        •those less suited to the environment are less likely to survive and so have less chance to pass on their alleles, allowing the population to be better suited over time 

        •variations that are caused by the environment itself e.g losing a finger aren't involved in natural selection 

                  •variations in a species can have environmental or genetic causes, but only genetic ones are passed on - the environment influences the survival of the genetics