Evolution- (5) Mechanics of Evolution Flashcards
What are mutations?
A change in DNA, which can then impact an entire gene pool. The more genetic diversity(mutations) in a population, the greater chance the population survives.
What is gene flow?
The net movement of alleles from one population to another as a result of the migration of individuals.
Give an example of gene flow
Grey wolves may travel over 800km to find new territory/ a mate. Often, a wolf from one population will mate with a member of a nearby population, thus increased genetic diversity.
What is Non-Random mating?
Mating among individuals on the basis of mate selection for a particular phenotype or due to interbreeding.
What is meant by mating for Preferred Phenotypes?
Individuals may choose mates based on physical and behavioral traits.
Whats an ex of breeding for preferred phenotypes?
Female greater sage grouse. In herds, males compete for mates by using their antlers to spar against other males. This prevents small- antlered males from reproducing.
What is inbreeding?
When closely related individuals breed together.
Whats the dangers of inbreeding?
Close relatives share similar genotypes, so inbreeding increases frequency of homozygous genotypes. This can result in harmful recessive alleles more likely to be expressed.
What is genetic drift?
The change in allele frequencies due to chance events in population. Larger populations have a better chance of survival vs small populations. Sometimes genetic drift can cause gene variants to dissipate completely, or cause some alleles to become fixed.
Whats the founder affect?
When a small group of individuals “founders”, establish a new population.
Why might the founder affect decrease genetic diversity?
These founders may not represent all the genetic diversity of original population.
Whats an example of the founder affect?
Strong winds carry a pregnant fruit fly to a new island. The new population does not represent the full genetic diversity of og population, therefore when the new population mates with another population certain traits may become more or less fequent.
Whats the bottleneck affect?
Events like natural disasters can decimate a population, killing most individuals and leaving behind a small and random assortment of individuals.
Give an example of the bottleneck affect?
A typhoon devastated an island and 30/16000 individuals survive. 1 survivor carried CVD, and the current day popuation traces back to this person, bc now up to 10% have CVD. In general population CVD is pretty rare.
Explain stabilizing selection
Favours intermediate phenotypes and acts against extreme variants. The most common phenotype- the intermediate form- becomes most prevalent.
