Natural selection + Gene Flow & Drift

What is Allele Frequency and What causes changes (4)?

the proportion of a particular allele within the gene pool of a population. changes are caused by natural selection, genetic drift, gene flow and mutation

What is Natural Selection?

the process where environmental selection pressures favour individuals with certain inheritable phenotypes, those individuals have reproductive success and advantageous alleles become more prevalent

What are Environmental Selection Pressures? (+ 7 examples)

factors in the environment that affect an organisms ability to survive and reproduce eg. predation, competition, disease, temperature, availability of food/water, salinity, antibiotics

What are the main principles for Natural Selection? (6)

variation exists, some variation is inheritable, organisms produce more offspring than can survive, competition for limited resources, advantageous phenotypes

What is Gene Flow and what does it do (3)?

movement of alleles between populations due to migration of individuals. it can increase genetic variation, introduce new alleles, change allele frequency

What is Genetic Drift?

a random change in allele frequency due to chance events that randomly affect which individuals survive and reproduce

What is the Bottleneck effect? (+ an example)

a form of genetic drift where a large population is drastically reduced in size by a chance event leaving a small population with a different allele frequency eg. a natural disaster randomly kills most individuals in a population

What is the Founder effect?

a form of genetic drift that occure when a small group of individuals become isolated from a larger population to establish a new population

What is the difference between Natural Selection and Genetic Drift?

natural selection is a non-random process where environmental selection pressures favour individuals with advantageous phenotypes. in contrast, genetic drift is a ranom process where chance events cause allele frequency to change