Genetic Variation & Mechanisms of Evolution

Genetic variation - high vs low genetic diversity

•Higher genetic diversity: higher chance of survival of a population

•Lower genetic diversity: higher chance of extinction of a population, inbreeding

What causes genetic variation in a gene pool?

o Mutations: a single mutation can have a large effect, but in most cases, evolutionary change is based on the accumulation of many mutations with small effects - brand new alleles!

o Gene flow: movement of genetic material from one population to another

o Reproduction: genetic shuffling from recombination - new combinations of existing alleles

Types of mutations

-Beneficial mutations: cause a change in gene expression that increases fitness

-Deleterious (harmful) mutations: a change that decreases fitness

-Neutral mutations: a change that has no positive or negative effect on fitness (or no change at all)

Traits vs adaptations

Traits

- Who people are (behaviorally)

Adaptations

- What people want to become

- How they view the world / themselves

- How these processes change with development

4 mechanisms of evolution

o Natural Selection: the process by which individuals with traits better suited to their environment survive

o Mutation: Change in DNA sequence - usually occurring because of errors in replication or repair

o Gene flow: Exchange of alleles between two or more separate populations of the same species

o Genetic drift: Random fluctuations in the frequency of an allele in a population from generation to generation

-Founder effect: The founder effect is when a new population is started by a small group of individuals, causing reduced genetic variation and differences from the original population.

-Bottleneck effect: The bottleneck effect occurs when a population's size is drastically reduced by an event, leading to a loss of genetic diversity in the surviving population.

Artificial selection

selective breeding - picking what and who we breed together