Unit 7 Flashcards
(88 cards)
Evolution
Change in the gene pool of a population over time
- All living beings are from the same source
- Change over time
What are the four mechanisms of Evolution? (4)
- Natural Selection
- Mutation
- Genetic Drift
- Gene Flow
What is Natural Selection and its result?
The idea that the fittest survive and have more offspring.
Result: Adaptation
1. Increasingly well suited
2. Acts on existing heritable variation *
What is Genetic Drift
random loss of alleles
example: only breeding dominate, resulting in fixation
Fixation
Where one allele goes to 100%
What are the two examples of the Genetic Drift?
- Bottle Neck Effect
- Founder Effect
What is the bottle neck effect
When a disaster causes reduction of genes
What is the founder effect
When a sample of alleles moves to a different area to reproduce, excluding other alleles
What population is Genetic Drift relevant to?
Small populations
What is fitness depended on? (2)
- Survival
- Mate ability
Stabilizing Selection
Where the intermediate (mild form) of the trait is the fittest
Disruptive Selection
Where both* extremes of the trait is the fittest
Directional selection?
Where either* one of the extremes are the fittest
What is Gene flow?
where a movement of one gene to another population
Allele Frequency?
How common an allele is in a population
How do you calculate the percentage of an allele?
(Allele Frequency) = {(#of alleles)/(total number of copies of gene in population)}
What is population genetics
the study of allele frequencies in a population and how they change
Gene Pool
All copies of all genes in a population
Microevolution
small changes in a population, which is the smallest unit for evolution
Macroevolution
Large changes involving multiple populations
What does the Hardy-Weinberg Equation used for?
It is to make a general approximation of allele frequencies
What does the Hardy-Weinberg Equation assume? (5)
- No mutation
- Random mating
- No gene flow
- Large population
- No natural selection
i.e.
1. Stable allele frequency
2. No Evolution
what is the Hardy-Weinberg Equation
(p+q)^2
p+q = 1
P^2 = homo Dominant
2pq = hetero Dominant
q^2 = homo recessive
What are the four
ways for the evidence of evolution?
- Structural - Morphology
- Molecular - DNA
- Observation - fossils
- Biogeographical evidence