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34 Cards in this Set

  • Front
  • Back
Particulate model of genetics
Mendel: traits are passed on in particles (opposite of blending hypothesis)
Group of interbreeding individuals
When only one allele is at a locus (ie if everyone who had a red lifesaver could not reproduce), everyone then becomes homozygous for that allele
Gene Pool
Sum of all alleles across loci (bag of life savers)
Allelic frequency
# of red
# of white
Genotypic frequency
# RR
# Rr
# rr
Genetic load
pool of deleterious (bad) alleles in a population
No evolution if:
No selection (everyone equal)
No Mutation
No Migration
No Genetic Drift (Infinite pop size)
Random Mating
increases variation-adds alleles, major source of variation, most are bad, then neutral, least are beneficial
input of new alleles from another population
Genetic drift
on average reduces variation->propels a population to fixation; random deviation from expectation (more drift with smaller samples)
shrinks population, shifts frequencies
Founder effect
emigrate out and result in rapid changes (sever bottleneck)
Assortative mating
like mates with like; tend toward excessive homozygotes
Disassortative mating
like mates with unlike; tend toward excessive heterozygotes
Inbreeding depression
shared sickness among close relatives (hemophelia)
contribution to next generation
Relative fitness
relative contribution to the rest of the population
Stabilizing selection
phenotypes in the mean are favored
Directional selection
one extreme is favored over another (reduces variation)
Diversifying (disruptive) selection
extremes are favored (expand variation)
Sexual dimorphism
differences between sexes; behavioral and morphological (body characteristics)
features of both sexes in 1 individual
In the gene pool of a population with 100 individuals, a fixed allele for a particular gene locus has a frequency of
Researchers examining a particular gene in a fruit fly population discovered that the gene can have either of two slightly different sequences, designated A1 and A2. Further tests showed that 70% of the gametes produced in the population contained the A1 sequence. If the population is at Hardy-Weinberg equilibrium, what proportion of the flies carries both A1 and A2?
At a locus with a dominant and a recessive allele in Hardy-Weinberg equilibrium, 16% of the individuals are homozygous for the recessive allele. What is the frequency of the dominant allele in the population?
The average length of jackrabbit ears decreases gradually with increasing latitude. This variation is an example of
directional selection
Longer tails of male barn swallows evolve because female barn swallows prefer to mate with the males that have the longest tails. This process is best described as
intersexual selection for traits, such as long tails, that help males attract mates.
Road construction has isolated a small portion of a beetle population from the main population. After a few generations, this new population exhibits dramatic genetic differences from the old one, most likely because
allele frequencies among the stranded beetles differed by chance from those in the parent population's gene pool and subsequent genetic drift caused even more divergence from the original gene pool.
What are the expected genotype frequencies for a population at Hard-Weinburg equilibrium, where there are two alleles at a locus, p an q, and p=.2?
Which of hte following increases the genetic variation in a population?
C)Stabilizing selection
D)Answers a and b
E) All of the above
D) Answers a and b
(mutation and migration)
Male deer clash antlers in order to compete for mates. This is an example of:
intrasexual selection
How woul dyou test if the following population was in H-W equilibrium?
Genotype: AA Aa aa
Frequency: .33 .34 .33
find p (A) by .33+1/2(.34)
then find q (a) by 1-p
Then do p^2+2pq+q^2, which does not equal 1.
Red queen hypothesis
keep evolving to not lose place; unifying theory of evolution