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BIO 206 Final Exam Questions and Answers (Success)
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BIO 206 Final Exam Questions and Answers (Success)
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©PREP4EXAMS@2024 [REAL EXAM DUMPS] Tuesday, July 23, 2024 10:52 AMBIO 206 Final Exam Questions and Answers (Success)
Homoplasy - ✔️✔️A similar (analogous) structure or molecular sequence that has evolved
independently in two species.
Problems with Homoplasy - ✔️✔️It can create an unpredictable gain or loss of a specific trait over
time and during the evolution of new species
Slowly evolving genes - ✔️✔️Useful for distantly related species
Rapidly evolving species - ✔️✔️useful for closely related species
Most useful traits - ✔️✔️Shared derived traits
convergent evolution - ✔️✔️repeated evolution of a trait
Homology - ✔️✔️Similarity in characteristics resulting from a shared ancestry.
Synapomorphies - ✔️✔️shared derived characteristics that evolved in a common ancestor of the
group and were inherited by all of its descendants
Evolution - ✔️✔️change in allele frequencies through time
Population genetics - ✔️✔️- tracks the fate, across generations, of alleles in populations
- concerned with whether a particular allele or genotype will become more or less common over
time, and WHY
single locus polymorphism - ✔️✔️genes that control a single trait
additive ("incomplete dominance") - ✔️✔️allele yields twice the phenotypic effect when 2 copies
are present (phenotype is in-between)
5 Hardy Weinberg Assumptions - ✔️✔️1. No selection
2. No mutation
3. No migration
4. No chance events
5. There is random mating
Primary uses of HWE - ✔️✔️- compute genotype frequencies from generation to generation
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,©PREP4EXAMS@2024 [REAL EXAM DUMPS] Tuesday, July 23, 2024 10:52 AM
- null model in tests for evolution (compares observed to expected)
- forensic analysis
Common mistake of HWE - ✔️✔️- Population is in HWE because it sums to 1, this is just to check
your math
* To determine HWE you need to COMPARE observed to expected *
Genetic Drift - ✔️✔️- A change in the allele frequency of a population as a result of chance events
rather than natural selection
- Alleles are "sampled" to form progeny
Finite Population - ✔️✔️- Chance events
- Randomly pair egg and sperm to make zygotes. If population is finite in size, WILL NOT GET
allele frequencies in their exact proportions
Genetic Bottleneck - ✔️✔️Non-representative set of alleles for subsequent populations, even after
the population size rebounds
Founder Effect - ✔️✔️- Type of genetic bottleneck resulting from a small number of individuals
colonizing a new, isolated habitat
- Not representative of source population
Properties of genetic drift - ✔️✔️- DIRECTION of change in allele frequency can NOT be
PREDICTED
- One allele will eventually be fixed, the other eliminated: genetic drift tends to REMOVE
VARIATION
- Probability that a particular allele will eventually be fixed (or lost) is proportional to its
frequency in the population
What does drift do to genetic diversity? (One word) - ✔️✔️Reduces
3 main features of genetic drift - ✔️✔️- loss of genetic variation results WITHIN populations (1
allele will eventually be lost or fixed)
- Genetic divergence results BETWEEN populations (populations become more different by
chance)
- Drift CAUSES evolution, but NOT adaptive evolution
Fitness - ✔️✔️expected reproductive success of an individual with a particular phenotype (or
genotype)
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, ©PREP4EXAMS@2024 [REAL EXAM DUMPS] Tuesday, July 23, 2024 10:52 AM
3 components of fitness - ✔️✔️- survival to reproductive age
- mating success
- fecundity
Absolute fitness equation - ✔️✔️(probability of survival) * (average number of offspring)
Relative Fitness - ✔️✔️Fitness of a genotype standardized by comparison to other genotypes
Change is fastest when the selection is _____________ (ie; larger differences in relative fitness)
and allele frequencies are ___________ - ✔️✔️strong; similar
Additive (relationships among alleles at a locus) - ✔️✔️allele yields twice the phenotypic effect
when two copies present
Dominance - ✔️✔️dominant allele masks presence of recessive in heterozygote
Directional Selection - ✔️✔️1 of the 2 alleles has higher fitness than the other one
Selection coefficient (s) - ✔️✔️Fitness disadvantage to (or strength of selection against) a
genotype
s=1-w
Dominance Coefficient (h) - ✔️✔️Proportion of s applied to the heterozygous genotype
hs = 1 - w
h = hs/s
Heterozygote advantage (overdominance) - ✔️✔️- heterozygote has greater fitness than either
homozygote
- results in stable equilibrium polymorphism
Heterozygote Disadvantage (Underdominance) - ✔️✔️- when a heterozygote has a lower fitness
than either homozygote
- results to unstable equilibrium polymorphism
Negative Frequency Dependent Selection - ✔️✔️- An allele becomes LESS fit as it becomes more
common
- Multiple alleles will be maintained in a stable polymorphism (both alleles are maintained),
promotes genetic diversity
- Fitness is GREATEST when the phenotype is RARE
Ex; pathogen, mating, resource use, predation
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