Where are substitutions more common? - ANSWERSat positions that do not change the amino acid
What does neutral mean? - ANSWERSdon't convey a selective advantage or disadvantage
What does the molecular clock do? - ANSWERShelps you calculate how long it has been since two species "diverged" fro...
Biology Evolution Exam 3 Questions &
Answers
Where are substitutions more common? - ANSWERSat positions that do not change the
amino acid
What does neutral mean? - ANSWERSdon't convey a selective advantage or
disadvantage
What does the molecular clock do? - ANSWERShelps you calculate how long it has
been since two species "diverged" from a common ancestor
What is positive directional selection? - ANSWERSrate of non-synonymous substitution
exceeds the rate of synonymous substitution
What is neutral selection? - ANSWERSrate of non-synonymous substitution equals the
rate of synonymous substitution
What is a form of stabilizing or purifying selection? - ANSWERSrate of non-synonymous
substitution is less than the rate of synonymous substitutions
Where is genetic drift stronger: smaller or larger populations? - ANSWERSsmall
populations
What does sexual recombination lead to? - ANSWERSleads to genetic variability in
offspring
What are some of the disadvantages of sexual reproduction? - ANSWERSonly 50% of
the female genes are passed on; recombination separates adaptive gene combinations
What are the advantages of sexual reproduction? - ANSWERSrecombinations can
separate deleterious combinations; homologous chromosomes are used to repair
damaged DNA; recombination introduces genetic variation
What is the main advantage of asexual reproduction? - ANSWERSincreased fitness
What are some of the disadvantages of asexual reproduction? - ANSWERSno way to
eliminate deleterious mutations
What is lateral or horizontal gene transfer? - ANSWERSprocess by genes, organelles,
or fragments of entire genomes move from one lineage to another
, What is gene duplication? - ANSWERSentirely new copy of a gene appears in a
genome over evolutionary time
What is a gene family? - ANSWERSgroup of homologous genes that have related
functions
What is speciation? - ANSWERSprocess in which biological lineages diverge due to
reproductive isolation, resulting in new species
What are sister species? - ANSWERSeach one is the other's closest relative
What is the morphological species concept? - ANSWERSdefines a species based on
observable morphological characteristics such as body shape, size, color, and other
structural features
What are some of the problems of the morphological species concept? -
ANSWERSmembers of the same species may look alike; members of the different
species may look similar
What is the biological species concept? - ANSWERStwo organisms are of the same
species if they can mate with one another
What is the main idea of the biological species concept? - ANSWERSgroups of actually
or potentially interbreeding natural populations that are reproductively isolated
What is reproductive isolation? - ANSWERSsituation in which two groups of organisms
are unable to exchange genes
What are the disadvantages of the biological species concept? - ANSWERSdoes not
apply to asexual organisms; cannot be applied to extinct species; ring species are too
distantly related to interbreed
What is the lineage species concept? - ANSWERStwo groups that share a branch on
the tree of life
What does speciation require> - ANSWERSrequires an interruption in gene flow
What does the Dobzhansky-muller model explain? - ANSWERSexplains how a single
lineage can split into two reproductively isolated species; overtime, the two species will
be unable to mix and will be considered two different species
When does reproductive isolation increase? - ANSWERSwhen a species diverges
genetically
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