ch 12 b Flashcards
microevolution
evolution at the molecular (gene) level; doesn’t necessarily involve formation of a new species
gene variation
necessary for evolution; results from mutations in combination with sexual reproduction
average heterozygosity
the average % of loci that are heterozygous
geographic variation
difference in genetic composition of separate populations
evolution
generation to generation change in a population’s frequency of alleles
True or False: the hardy-weinburg only looks at one allele at a time
true
5 unlikely situations of the Hardy-Weinburg Theorem
- Allele and genotype frequencies never change from one generation to the next
- mutations do not occur, so no new alleles rise
- large population
- Individuals mate randomly
- individuals remain in their own population
What are the three types of natural selection?
- Directional Selection
- Disruptive selection
- Stabilizing selection
What is the Hardy-Weinburg Equation?
p^2+2(p)(q)+q^2=1
What is sexual dimorphism
Appearances of male and female differ in order to aid in reproductive success, can also scare off predators
How do mutations lead to evolution?
A change in an organism’s DNA sequence can lead to a new allele to be introduced into a population. The effect of the mutation on a protein sequence can determine if a new trait is beneficial
Genetic Drift
Change in allele frequency, eliminates alleles from a population and occurs by chance
3 points of genetic drift
- small population
- only few reproduce and lose alleles in the next population
- reduces variation
What is the founder effect?
Occurs when a small group of individuals leaves home and isolates themselves into a new community
What are the 2 examples of genetic drift?
- Founder effect
- Bottleneck effect
What is the bottleneck effect?
results when a population reduces greatly over a short period of time
Random mating and example
every individual has an equal chance of mating (ex. plants pollinated by wind)
Non-random mating two factors
- geological restrictions
- attractions such as calls
gene flow
moves alleles from one population to another, helps with genetic diversity
directional natural selection
one extreme phenotype is the fittest and the environment doesn’t support others (moths in england)
disruptive selection
two or more phenotypes are more fit and the intermediate phenotype (rabbits)
stabilizing selection
extreme phenotypes are less fit than the intermediate optimal phenotype
intrasexual selection
the members of one sex compete among themselves for access to the opposite sex (fighting)
intersexual selection
the members of one sex choose their mates from among multiple individuals of the opposite sex (appearance)
