Lecture 4 & 5 Flashcards
(37 cards)
Microevolution
change in allele frequencies in a population over time
What are the four processes that drive out populations?
1-Mutations
2-genetic drift
3-geneflow
4-selection
What is the purpose of equilibrium
allows us to identify forces that drive microevolutionary change
Who created the control model?
Hardy Weinberg
What happens in the HW model?
it has no mutations, is fully isolated, allele has no effect on survival or reproduction, & all mating is random
What is the purpose of the HW model and what is the general use of the control models in biology?
-it can be used as the control model, testing the conditions for evolution not to occur
-it allows us to identify the forces that drive microevolution change
What does fitness affect?
Lethal mutations (death of species)
Deleterious mutations (harms one’s fitness)
Neutral mutations (no effects)
Beneficial mutations( increase fitness)
What is genetic drift?
allele randomly become fixed causing a loss of alleles (affect fitness)
Why does Drift come about?
Bottle Neck events and founder effect
What is the bottleneck effect?
a catastrophe that causes the population to collapse
What is the founder effect?
people from a population start a new population with different allele frequencies
How can genetic drift cause concern?
lead to inbreeding can cause harmful alleles to become fixed in a population
Examples of genetic drift?
greater prairie chicken
Migration
movement of alleles between populations
Gene flow
the transfer of alleles from the gene pool of another population
Directional Selection
allele frequencies give rise to a range of variation
Stabilizing selection?
the middle trait of a species favored
Disruptive Selection
favors both ends of traits in the population & not the intermediate
Translocation
taking individuals from one population and moving them to different area
What is speciation?
ancestral species gives rise to a pair of daughter species
What are the 3 steps of the classic model?
1-isolation of populations
2-divergence in traits
3-reproductive isolation
What is gene flow?
exchange of genetic information
What is Allopatric Speciation?
A physical barrier arises and stops geneflow between 2 populations
Examples of barriers?
mountains, ocean
