Adapataions

Can only occur in a genetically diverse environment ( Lots of different allele combinations in one population)

Favourable alleles that give adaptions that suit the host best for its environment

Structural/Physical adaptations e.g White fur of a polar bear help camouflage into snowy environment

Biological processes within the organism e.g Mosquitos produce chemicals that stop the animals blood clotting when they bite so they can feed easier

The way an organism behaves e.g Cold blooded reptiles bask in the sun to absorb heat S

The selection that keeps the frequencies of alleles relatively constant over generations ( Selects against the extreme phenotypes and selects for the intermediate phenotypes) Usually happens when there is no change in environment

Natural selection that produces a gradual change in allele frequencies over several generations (Favours one extreme phenotypes which causes the mean trait value to change over time) Usually happens when there is a change in environment

1) New alleles for a gene a created by a random mutation 2) If the alleles increase the chances of that individual surviving in that environment then they are more likely to reproduce 3) This reproduction passes on the advantageous allele to the next generation 4) As a result, over many generations. the new allele frequency increases in the population