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BIOL 1200- Midterm Exam Guide - Comprehensive Notes for the exam ( 33 pages long!)Premium

33 pages122 viewsSpring 2017

Department
Biology
Course Code
BIOL 1200
Professor
Trip Lamb
Study Guide
Midterm

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ECU
BIOL 1200
MIDTERM EXAM
STUDY GUIDE
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How does antibiotic resistance evolve in populations? What is the agent of
selection?
Natural selection to a new environment. Antibiotics.
Ex. If a bacterium is resistant to antibiotics, it will be favored to reproduce.
How does Darwin’s concept of descent with modification explain both the
unity and diversity of life?
Favorable traits are passed down, which is descent with modification,
which causes new species but at the same time, all species are linked
through common ancestors.
Genetic terminology review
Know the following terms: allele, gene, locus, homozygous, heterozygous,
codominance, replication, transcription, translation, proofreading, point
mutation, silent, missense, and nonsense mutations
Allele: Variant form of a given gene. (Produces distinguishable
phenotypes).
Gene: Segment of DNA codes for a protein.
Locus: Location of a gene on the length of a chromosome.
Homozygous: Having two identical alleles for a given gene.
Heterozygous: Having two different alleles for a given gene.
Codominance: Phenotypes of both alleles are exhibited in the heterozygote
because both alleles affect the phenotype in separate, distinguishable ways.
Replication: When new DNA is recreated from old DNA.
Transcription: Where DNA is copied onto mRNA.
Translation: Where the code carried by mRNA is coded into amino acids.
Proofreading: DNA polymerase’s ability to check over DNA to look for
mistakes.
Point Mutation: Mutation where only one nucleotide is affected.
Silent Mutation: Point mutation where the same amino acid is coded for.
Missense Mutation: Point mutation that codes for a different amino acid
and affects phenotype.
Nonsense Mutation: Causes reading of the stop codon too early.
Evolution of populations (Chap 21)
Define microevolution.
Microevolution: Change in allele frequencies over a short time within a
population.
Review the medium ground finch study discussed in lecture (and text).
What are the sources of genetic variation?
Mutation, gene flow, sex.
What is a gene pool?
The stock of different genes in an interbreeding population.
What is the Hardy-Weinberg (H-W) principle? Did Hardy and Weinberg work as
a team?
Genotypic and allele frequencies don’t change from generation as long
other evolutionary factors are not present. Yes.
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When is a population in H-W equilibrium? What assumptions (conditions) must
be met?
If the allele frequencies don’t change or are near the expected values.
Random mating, no natural selection, no gene flow, extremely large
population size (no genetic drift), no mutation.
Why is H-W equilibrium characterized as the null hypothesis of population
genetics?
Because it tests whether evolution or nonrandom mating is occurring for a
particular gene.
How many generations of random mating are required to reach H-W
equilibrium?
One, if all the conditions required are met.
What happens to allelic and genotypic frequencies once a population is in H-W
equilibrium?
Nothing, they are in stasis.
How do you evaluate whether or not a population is in H-W equilibrium?
Calculate allelic frequencies to see if genotypic frequencies meet the
expected frequencies.
Why would allele or genotype frequencies change in a population?
Natural selection, nonrandom mating, gene flow, genetic drift, mutation.
In what ways does mutation differ from other forces responsible for evolution?
Mutation can be spontaneous and creates new alleles/new genetic
variation.
What is relative fitness?
Contribution an individual makes to the gene pool of the next generation
relative to the contributions of other individuals in the population.
(An individual’s ability to produce surviving offspring, relative to others in
the population).
Describe the differing outcomes of directional, stabilizing, and disruptive
selection.
Directional: Where average increases.
Stabilizing: Reduction in variation.
Disruptive: Increase in variation, selection against the mean, bimodal
distribution. (Extreme values for a trait are favored over intermediate
values. Variation increases and the population is divided into two distinct
groups).
What is genetic drift? What is its role with regard to fitness?
A change in allele frequencies just by chance. The loss of potential
favorable alleles can reduce fitness.
(Change in the frequency of a gene variant (allele) in a population due to
the random sampling of organisms).
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