Upgrade to remove ads
Evolution Exam 2
Terms in this set (30)
What three factors contribute to linkage disequilibrium?
1. multilocus selection
What is the formula for D, coefficient of linkage disequilibrium?
D = gABgab - gAbgaB
What is the mathematical relationship between the frequency of a gamete in this generation versus its frequency in the last generation?
D' = D(1-r)
r = recombination frequency
What is the advantage of asexual reproduction over sexual reproduction? Explain.
easier, less complicated, less costly and less dangerous than sexual reproduction
no meiosis, which is a very complex and error prone process
How does selection favor sexual reproduction over asexual?
sexual reproduction yields progeny with higher fitness values because meiosis is where the vast majority of mutations occur. Mutation is too uncommon to happen a lot with cloning
How does a changing environment favor sexual reproduction over asexual?
recreation of new genotypes, genotypes without deterious alleles, and genotypes previously lost by selection in a changing environment can only occur in sexual selection
Define S, the selection differential, with regard to quantitative traits.
Difference between the means
Variance for a trait
What is the mathematical relationship between heritability, selection differential, and selection response?
R = h^2 * S
Name three patterns of selection on quantitative traits and indicate what values of a trait have highest and lowest fitness (low values, high values, or mid values).
a. Directional selection
highest fitness at one end
lowest fitness at one end
b. Stabilizing selection
highest fitness in the middle
lowest fitness at the ends
c. Disruptive selection
highest fitness at the ends
lowest fitness in the middle
Consider the adaptive landscape model of Sewell Wright. How is it possible that a population is prevented from reaching the highest possible mean fitness for the species? Name three factors that might "help" a population attain the highest mean fitness possible.
What are three cautions noted by researchers studying the adaptation of traits to the environment?
1. not every trait is an adaptation
2. differences between populations are not always adaptive (drift, founder effect, etc)
3. adaptations are not necessarily perfect
What were three of the alternative hypotheses?
1. No mimicry occurs
2. Mimicry deters predators other than jumping spiders
3. Mimicry deters jumping spiders
What was the purpose of reattaching the same wings that had been cut off of the Zonosemata?
To test if the act of cutting and reattaching itself had any effect
What was the conclusion of the Zonosemata experiment?
The flies with both the behavior and patterns deterred the jumping spiders, but not other predators.
What was the hypothesis of the comparative study correlating testes size and mating system in primates?
males in multi-male systems should have larger testes per body weight than males in the dominant male or monogamous systems
What three pieces of data were collected on each primate group in the comparative study correlating testes size and mating system in primates?
1. which type of mating system
2. body weight of males
3. testes weight
What was the final conclusion of the comparative study correlating testes size and mating system in primates?
larger males have smaller testes
testes size in primates is an adaptation to fecundity selection
How does phenotypic plasticity differ from evolutionary adaptation?
phenotypic plasticity - phenotype of an individual changes in response to environmental change
evolutionary adaptation - traits of a population change (by allele frequency change) due to environment
Briefly describe three hypotheses given to explain why females might choose certain male traits.
a. genetic quality - it requires a lot of energy to defending against parasites; only the best genotypes would be able to make such a fabulous display
b. runaway selection - stalk eyed flies
c. positive assortative mating - inheriting traits...
From the asymmetry in contribution to sexual reproduction what are the limiting factors to maximum reproductive potential for males versus females?
Males - number of mates
Females - energy and resources
Differentiate between intrasexual competition and intersexual competition among males.
intrasexual - involves only males (female choice is not involved)
intersexual - involves female choice; displays chosen by females
Why are male perianths of dioecious species sometimes bigger even though the female reproductive organs are larger?
larger perianth on staminate flowers is an adaptation to sexual selection
Define linkage disequilibrium
the non-random association of alleles at different loci
Define linkage equilibrium
the completely random association of alleles at different loci
Explain how drift can result in linkage disequilibrium.
causes some allele combinations to become more or less common
Explain how selection of genotype combinations can result in linkage disequilibrium.
causes those genotype combinations with higher fitness values to become more common
What eliminates linkage disequilibrium?
What happens to gamete frequencies in a population in linkage equilibrium?
they stay the same
What happens to gamete frequencies in a population in linkage disequilibrium?
List the three types of intrasexual competition discussed in class. Which is most common in natural populations?
infanticide (most common)
YOU MIGHT ALSO LIKE...
Lecture 14- Natural Selection
Non-Random Mating/Sexual Selection
Chapter 13 Evolution
Biology 142 exam 3 UMBC
OTHER SETS BY THIS CREATOR
Psych Exam 4
EC Exam 3 Regular
EC Exam 3
OTHER QUIZLET SETS
A&P II Lymphatic System
Ap study terms 8
Kleidung machen Leute
leadership and management SNCOA test