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Gen. Bio II - Evo.
General Biology II - Evolution of Populations
Question | Answer |
---|---|
the smallest unit of evolution are | populations |
the impact of natural selection is only apparent in populations____________________ | over time |
microevolution is | the change in allele frequencies in a population over generations |
what are three mechanisms of microevolution | 1) natural selection, 2) genetic drift, 3) gene flow |
just a few years after Darwin published his essay, Gregor Mendel started studying ______________ | peas |
who set the stage to understanding genes and genetic variation | Gregory Mendel |
evolution would be impossible without ______________________________ | genetic variation |
individuals within species vary in specific characteristics , is an example of what? | genetic variation leads to variations in specific characteristis |
genetic variations are often reflected by ___________________ | phenotypic variations |
name the four sources of genetic variation | 1) formation of new alleles, 2) altering gene number or position, 3) rapid reproduction, 4) sexual reproduction |
new alleles are formed by _________________ | mutations |
a mutation is a change in ___________________ sequence of an organisms DNA | nucleotide sequences |
(high/slow) reproduction rates have lower mutation rates | high mutation rates = lower mutation rates |
_____________________ results in unique combinations of alleles | sexual reproduction |
what kind of reproduction allows the shuffling of existing alleles | sexual reproduction involves shuffling of existing alleles |
what is a group of individuals of the same species living in the same area, interbreeding, and producing fertile offspring | population is the group of individuals of the same species living in the same area, interbreeding, and producing fertile offspring |
what is a gene pool | all copies of every type of allel at every loci in all member of the population |
in Hardy-Weinberg what does "p" represent | the frequency of the dominant allele |
in Hardy-Weinberg what is the frequency of the recessive allel | q |
the Hardy-Weinberg represents populations that (are/are not) evolving | Hardy-Weinberg represents populations that ARE NOT evolving |
name the five conditions that need to exist for the Hardy-Weinberg Equilibrium | 1) No Mutations, 2) Random Mating, 3) no natural selection, 4) extremely large population size, 5) no gene flow. |
what is the medical application for the Hardy-Weinberg equation | medicine- determining what percentage of the population is carrying an allele for inherited diseases |
what three things disrupt the Hardy-Weinberg equilibrium | 1) genetic drift, 2) natural selection, 3) gene flow |
why is genetic drift not ideal fro the hardy-weinberg equilibrium | genetic drift causes allele frequencies to fluctuate unpredictably, one generation to the next |
genetic drift has the greatest effect on (small/large) populations | small populations |
what two type of genetic drifts can have significant impact on populations | 1) founders effect, 2) bottleneck effect |
the ____________________ effect is the isolation of a few individuals from larger population, that lease to establishment of a new population (like colonization) | founders effect |
describe the bottleneck effect | a suddentenvironmental change that leads to the drastic reduction of population size (like Noah's Flood) |
what could lead to higher frequency of certain inherited disorders and lower levels of genetic variation over a long period of time | genetic drift |
what is the transfer of alleles into or out of a population due to movement of fertile individuals or their gametes | gene flow |
what is relative fitness | the contributions that an individual makes to the gene pool of the next generation relative to the contributions of others. |
natural selection acts more on (genotype/phenotype) | phenotype. |
name the three ways in which natural selection can alter frequency distributions in populations | directional selection, disruptive selection, stabilizing selection |
(directiona/disruptive/stabilizing) selection occurs when the phenotype favors one extreme over middle of the road | directional |
as a result of the directional shift, what happens to the bell curve | bell curve moves to one side or the other |
disruptive selection favors what phenotypes | disruptive selection favors the phenotype at both extremes |
disruptive selection is also known as _________________ selection | diversifying |
birth weights is an example of _________________ selection | stabilizing |
what is stabilizing selection | when natural selection favors only the middle |
___________________ leads to a "good match" between organisms and its environment | natural selection |
____________________ leads to sexual dimorphism | sexual selection |
what is sexual selection | individuals with certain inherited traits more likely to obtain mates |
what is sexual dimorphism | the difference of secondary sexual characteristics between males and females |
name the two types of sexual selection | 1) intrasexual selection, 2) intersexual selection |
what is intrasexual selection | when same sex individuals in the populations compete for the opposite sex (usually occurs with males) |
what is intersexual selection | when one sex chooses the mate of the opposite sex |
carriers of sickle cell anemia, do not get Malaria, this is an example of what | heterozygote advantage |
what is heterozygote advantage | when the heterozygote has greater advantage than homozygotes |
frequency - dependent selection is | when the fitness of the phenotype depends on how common it is in population |
evolution is limited by | historical constraints ; each species descends with modification from ancestral forms |
adaptations often comes with _________________________. example, structural reinforcements are compromised for agility (increased agility can also be more prone to sprains, torn ligaments, and dislocations) | compromises |