Download Biol 467 Evolution Study Guide 2 p 1 1) Describe and contrast the

Biol 467 Evolution Study Guide 2
p1
This is intended to be an exercise, i.e., practice for exam 2. It is NOT a complete list of material for which you are
responsible. Exams will concentrate on lecture material, but you are responsible for any concepts in the assigned
readings from the text book. In general, your text goes into more detail with examples than you will be examined on.
Understand the principles, be able to define all italicized or boldfaced terms, and be able to cite some examples (i.e., of
history, phenomena, or concepts) accurately without concerning yourself on memorizing every detail of every example
provided in the text.
Read each question carefully and, minimally, answer exactly what it asks. A complete answer will include an
explanation, e.g., definition of term, explanation of how or why, for all technical terms and concepts either posed in the
question or used in the answer. Your response should be balanced to address all aspects of the question, rather than
going into great detail about only part of it. Space for answering open-ended questions is limited on exams, so be
concise but make good use of all the space you have available to you.
1) Describe and contrast the major types of genetic mutations.
2) Outline the different forms of mutations that can cause changes in translation of amino acid sequences in
coding regions.
3) What is recombination? What is the importance of recombination in evolution and how does it affect the
rate of origin of new variation?
4) What are the “assumptions” of the Hardy-Weinberg principle, i.e., under what conditions can a locus be
in Hardy-Weinberg equilibrium?
5) Explain the significance of Hardy-Weinberg equilibrium as a null hypothesis in evolutionary biology.
Under what circumstances will it be rejected? What are the possible reasons for its rejection and what
are the conclusions that would be drawn in that case?
6) A population has genotype frequencies of A1A1 = 0.50, A1A2 = 0.40, A2A2 = 0.10. What is the
probabality of fixation of either the A1 or A2 alleles? What is the probablity of fixation of either A1 or
A2 alleles after one generation of random mating under the assumptions of Hardy-Weinberg
equilibrium?
7) Is a population with genotype frequencies of A1A1 90%, A1A2 10%, and A2A2 0% in Hardy-Weinberg
equilibrium? Show calculations with fractional values rounded to nearest 1%.
8) A population in Hardy-Weinberg equilibrium has A1A1 genotype frequency of 25%. What are the
frequencies of the A1A2 and A2A2 genotypes? Prove, with calculations, that the genotypes are in
equilibrium. Draw a graph showing the relationship of the three genotype frequencies to allele
frequencies in Hardy-Weinberg equilibrium.
9) A population has genotype frequencies of A1A1 = 0.20, A1A2 = 0.60, A2A2 = 0.20. What is the
probabality of fixation of either the A1 or A2 alleles, under a model of drift? What is the probablitiy of
fixation of either A1 or A2 alleles after one generation of random mating under the assumptions of
Hardy-Weinberg equilibrium?
10) A panmictic population with genotype frequencies of A1A1 40%, A1A2 40% and A2A2 20% is
subdivided into ten isolated demes of finite population size. Predict the genotype frequencies for this
locus for the ten populations (as percentages of the ten) after an infinite number of generations, under the
model of drift. Will the demes diverge from or converge on one another when you consider all loci,
instead of just this one? Why?
11) Contrast genetic drift with Hardy-Weinberg equilibrium, citing similarities as well as differences in
cause and effect.
12) Outline and compare the two models of genetic drift. What are the most important predictions of these
models and how do they relate to population size?
13) Explain how drift predicts the divergence of demes in a metapopulation.
14) Explain the theory of neutral evolution.
15) Under what special conditions will censused and effective population sizes be equal? What are the
definitions of each?
Biol 467 Evolution Study Guide 2
p2
16) What is FST, and what is its relationship to Nm? Describe the four basic biogeographic models of gene
flow.
17) Define inbreeding coefficient. Contrast the effects of drift and inbreeding on changes in genotype and
allele frequencies, with and without the effect of selection against deleterious recessives.
18) Explain the relationships of population size, heterozygosity (H), and the rate population growth (r) in
the context of the founder effect of genetic drift.
19) What are the effects of inbreeding?
20) Phenotypic traits and genotype frequencies that we observe in nature may have arisen by several
mechanisms other than by selection. Outline several methods that are available to measure selection or
infer that it is operating in nature.
21) What is an adaptation? How can traits be recognized as adaptations?
22) Use examples to explain how we know that selection can act at cross-purposes, thus independently, at
the levels of the gene, individual, and species.
23) Explain the relationships between absolute fitness, relative fitness, and the rate of change of allele
frequency.
24) The average fecundity of species-X is 10, but genotype A1A1 has 30% survivorship to reproductive age,
genotype A1A2 has 40% survivorship and genotype A2A2 has 50% survivorship. Assuming nonoverlapping generations, what are the absolute fitnesses of the genotypes? What are their relative
fitnesses? What is the average fitness? Set up, but do not solve, and equation that predicts the change in
frequency of allele A1 if 20% of the population is A1A1, 30% is A1A2, and 50% is A2A2.
25) Explain the dynamics of the change in allele frequency of a new advantageous recessive mutant allele in
a small population.
26) Explain the dynamics of the change in allele frequency of both 1) a deleterious recessive, and 2) a new
advantageous recessive mutant allele in small versus large populations.
27) Outline mechanisms for the maintenance of stable polymorphisms.
28) Contrast positive and inverse frequency dependent selection. How do they work and what is the
difference in their predicted outcomes?
29) If selection acts on fitness in such a way as to make species "climb adaptive peaks" within an adaptive
landscape, then how might an incipient species cross an "adaptive valley" to reach a new peak? What
does it mean to cross an adaptive valley?
30) Contrast the biological species concept and the phylogenetic species concept, highligting the most
important criterion for diagnosing a species in each?
31) Why might it be difficult to come up with a definition for "species" that applies in all cases?
32) Contrast geographic models of speciation.
33) Describe the forms of prezygotic isolating mechanisms.
34) Outline and define the mechanisms of reticulation (reticular evolution).
35) Contrast different potential outcomes of hybridization in the context of reticular evolution.
Biol 467 Evolution Study Guide 2
p3
Define each of the following as specifically as possible in one or two sentences at most. An example is not
a definition, and a term should not be used in the definition of itself. This is NOT a complete list of
terms, but it is pretty close.
allele
allozygous, autozygous
altruism
Alu-I
aneuploidy
assortative mating
character displacement
chronospecies
cline
coalescence
coefficient of selection
conversion
crossing over
cryptic species
deme
directional selection
Ensatina
Epigenesis
epistasis
fitness: absolute, relative, average, landscape
fixation
fixation index
genetic structure
genotype
haplotype
hemiplasy
heritability
heterosis
inbreeding coefcient
incomplete lineage sorting
indel
independent assortment
introgression
inversion
isolating mechanism: prezygotic, postzygotic
linkage equilibrium
meiosis
metapopulation
microevolution
mitochondrial Eve
monomorphic locus
neofunctionalization
neutral theory
nondisjunction
nonsynonymous substitution
paralogous genes
parapatric speciation
pericentric inversion
pleiotropy
ploidy: haplo-, diplo-, poly-, homo-, autopoly-,
allopoly-, etc.
polygenic trait
population size: censused, effective
postzygotic isolating mechanism
pseudogene
relative fitness
reticulation
transposons: DNA-, retroRobertsonian rearrangement
secondary contact
segregation distortion
selection:genic, individual, kin, group, etc.
selection: directional, stablizing, disruptive,
frequency dependent, etc.
selection, balancing: varying, antagonistic
sexual selection
speciation: sympatric, parapatric, allopatric, etc.
species: biological, phylogenetic, etc.
species: semi-, super-, chrono-, etc.
substitution: transition, transversion,
synonymous, etc.
synapsis
dominance: under-, over- co-, semitransilience
vicariance