Factoring Afects Flashcards
What is selective sexual selection?
Only certain phenotypes get chosen by mates, increasing the frequency of their alleles and decreasing those of the unchosen ones.
Example: Peacock fancy feathers in males are chosen to reproduce, while non-fancy tails are not.
How does differential migration affect gene frequency?
If a certain phenotype moves out of an area, the frequency of those alleles decreases.
Emigrate means to move out, while immigrate means to move in.
What happens to the frequency of alleles when long-necked giraffes leave a plain?
The frequency of alleles for long necks decreases.
Those that stay will have an increased frequency.
What is the principle of natural selection?
Certain phenotypes survive, increasing the frequency of their alleles while decreasing those of unsuccessful ones.
This is often summarized as ‘Survival Of The Fittest’.
What does the founder effect describe?
A small group of individuals separated from the main group may have a different frequency of alleles in their gene pool.
As the population grows, this frequency may differ significantly from the main group.
What is random genetic drift?
A change in allele frequency that occurs in small populations due to chance mating or luck.
Smaller samples may not conform to the overall ratio of alleles.
How does a small population’s genetic drift affect its future?
It can lead to dramatic changes in allele frequency, making the population too different for interbreeding with the main population, potentially resulting in two species.
Mutation plus random genetic drift can quickly change small populations.
What are mutations in the context of genetics?
Changes to a gene that are inheritable and produce new variations.
Most mutations are slight; if severe, they are typically fatal.
What is the significance of mutations affecting sex cells?
Only mutations that affect sex cells can cause a population to evolve.
These mutations will affect the frequency of alleles.
What role do mutations play in adaptation?
Occasionally, a new mutated gene may provide a trait that increases survival, allowing that individual to out-compete others in the population.
