Midterm 2 - Review
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
卡片预览 (24 张)
Nc is…
The census population size (number of elephants in the isolated population that you count).
Ne is…
The effective population size is the size of an ideal population that would undergo the same amount of genetic drift (loss of heterozygosity per generation)
Ne > 50 prevents… Ne > 500 prevents…
Ne > 50 prevents severe inbreeding. Ne > 500 prevents severe loss of alleles from drift.
T or F: Inbreeding alone does not change allele frequencies?
True
Why do small populations lose genetic variation?
Due to the issue sampling from a small gene pool leading to rate of loss proportional to Ne
Why do small populations decline in mean fitness caused by inbreeding?
Mating between close relatives that carry the same deleterious recessive allele, result in more homozygous recessive genotypes and lowers fitness.
Hardy-Weinberg Theorem
Predicts that no evolution will take place between generations in the absence of the evolutionary mechanisms: genetic drift, selection, mutation, non-random mating and migration.
What is population subdivision: Fst
Reduction in heterozygosity in local populations caused by genetic drift and inbreeding.
Fitness
The reproductive success of an individual with a particular phenotype
What are the 3 components of fitness?
• Survival to reproductive age • Mating success • Fecundity
Relative fitness, w
Genotype with highest absolute fitness, wmax = 1. Fitness of all other genotypes standardize by dividing by wmax.
When fitness effects oppose each other, what determines the direction of selection?
environment
True or False: 1. Population size influences power of drift and weak selection 2. Drift is more powerful in large populations 3.Selection is more powerful in large popualtions
• True • False • True
What are the 5 drivers of evolution?
• Mutation • Non-random mating • Gene flow • Genetic drift • Natural selection
Which factors produce the variation that make evolution possible?
• Mutation • Non-random mating
Which factors alter a population’s genetic composition
• Gene flow • Genetic drift • Natural selection
T or F: small populations have lower heterozygosity than the total metapopulation
True
T or F: Most fit genotype depends on environment?
True
Intrasexual Selection
Males fight over females
Ansiogamy
Differences in the size of gametes between sexes results in differential investment in reproduction
What may explain the difference in parental care between sexes?
Uncertain paternity 2. females have certain parentage and are investing in their offspring or those of their relatives. 3. Males have uncertain paternity and could be directed toward offspring not their own.
Operation sex ratio
• Investment differences between sexes can extend past fertilization. • Sex that invests more will be in shorter supply. • Ratio of males to females available for mating at a given time
Male-biased OSR
• Slower rate of reproduction by females often leads to male-biased OSR • Highest when OSR when female is pregnant or lactates for long periods of time and male does not assist with offspring care
Female-biased OSR
• High ratio of sexually active males to fertilizable females • Low ratio of males willing to accept eggs to females who despite male to incubate them.