genetic diversity and adaptations

Number of different alleles of genes in a population

● Variations of a particular gene (same locus) → different DNA base sequence ● Arise by mutation

● A group of organisms of the same species in a particular space at a particular time ● That can (potentially) interbreed (to produce fertile offspring)

● Enables natural selection to occur ● As in certain environments, a new allele of a gene might benefit its possessor ● By resulting in a change in the polypeptide (protein) coded for that positively changes its properties ● Giving possessor a selective advantage (increased chances of survival and reproductive success)

● Change in allele frequency (how common an allele is) over many generations in a population ● Occurring through the process of natural selection -Adaptation and selection are major factors in evolution and contribute to the diversity of living organisms

• Random gene mutations can result in [named] new alleles of a gene • Advantage In certain [named] environments, the new allele might benefit its possessor [explain why] → organism has a selective advantage • Reproduction Possessors are more likely to survive and have increased reproductive success • Advantageous allele is inherited by members of the next generation (offspring) • [named] allele increases in frequency in the population

Natural selection results in species that are better adapted to their environment: ● Anatomical - structural / physical features that increase chance of survival ● Physiological - processes / chemical reactions that increase chance of survival ● Behavioural - ways in which an organism acts that increase chance of survival

Mutations happen continuously and randomly. Exposure to antibiotics is the selection pressure, causing non-resistant bacteria to die and allowing resistant bacteria with the mutation to survive and reproduce.

Bacteria don’t have immune systems. Being resistant means they resist their effect, ie. they are not killed.