AP Bio Unit 7 Test

how did darwin's understanding of artificial selection lead him to propose the theory of natural selection?

darwin recognized that the effects of competition for resources in nature produced a similar result, as the process of a breeder who chooses organisms with specific phenotypes to pass on to the next generation.

The change in the genetic make up of a population over time is defined as

evolution

what is the independent variable?

The variable, that one manipulates controls or varies in an experimental study to explore its effects

what is the dependent variable?

The variable that is being measured or tested in an experiment

what are the driving mechanisms of evolution?

mutations, genetic drift, and migration

Darwin's observation that traits are heritable led him to the conclusion that

some individuals may be able to survive longer, in reproduce more than other members of the same species, thereby passing their genes to subsequent offspring, which could result in a change to the populations characteristics overtime

mutation

The changing of the structure of a gene resulting in a variant form that may be transmitted to subsequent generations caused by the alteration of single base units in DNA, or the deletion insertion or rearrangement of larger sections of genes or chromosomes

genetic drift

variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die, or do not reproduce

adaptation

A feature that arose and was favored by natural selection for its current function. helps an organism survive, and or reproduce in its current environment

bottleneck effect

The loss of genetic variation that occurs after outside forces destroy most of the population. The few individuals left to reproduce past their traits onto all of their offspring, which then may thrive without the competition of a large population

divergent evolution (divergent selection)

The accumulation of differences between closely related populations within a species, sometimes leading to speciation. It is typically exhibited when two populations become separated by a geographic barrier in experience different selective pressures that drive adaptations to their new environment.

convergent evolution

occurs when organisms that aren't closely related evolve similar features or behaviors often as solutions to the same problems. The process can result in matching body shapes, color patterns, or abilities.

adaptive radiation

The diversification of a group of organisms into forms filling different ecological niches

microevolution

A change in gene frequency within a population

analogous structures

features of different species that are similar in function, but not necessarily in structure in which do not derive from a common ancestral feature and which evolved in response to a similar environmental change

homologous structures

similar physical features in organisms that share a common ancestor, but the features serve completely different functions

gene flow

The transfer of genetic material from one population to another. It can take place between two populations of the same species through migration and is mediated by reproduction and vertical gene transfer from parent to offspring.

prezygotic isolation

The separation of different species, to keep them from creating offspring by preventing the gametes from forming a zygote

natural selection

A mechanism of evolution. Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success. This process causes species to change and diverge overtime.

allopatric speciation

occurs when a species separates into two separate groups that are isolated from one another. A physical barrier makes it impossible for them to bleed with one another.

sympatric speciation

involves the splitting of an ancestral species, into two or more reproductively, isolated groups without geographical isolation of those groups

punctuated equilibrium

when evolution occurs rapidly after a long period of stasis

directional selection

Selection towards one extreme phenotype

stabilizing selection

Selection towards the mean, and against the extreme phenotypes

disruptive selection

Selection against the mean. Both phenotypic extremes have the highest relative fitness.

niche

The match of a species to a specific environmental condition

habitat

The natural home or environment of a plant, animal or other organism

gradualism

A hypothesis, a theory, or a tenet, assuming that change comes about gradually, or that variation is gradual in nature and happens over time as opposed to in large steps

what were the results of the miller and urey experiment?

resulted in organic compounds in amino acids forming

what evidence supports the endosymbiotic theory?

it's supported by evidence that some organelles and eukaryotes have their own DNA similar to that of prokaryotes

habitat isolation

A form of reproductive, isolation, in which reproduction between two populations generally two species that are capable of interbreeding is restricted, because each population occupies a different habitat

temporal isolation

A reproductive barrier which prevents interbreeding between distinct but closely related species due to the differences in timing of mating receptivity, activity, or fertility

behavioral isolation

when species are reproductively, isolated from others due to differences in behavior

mechanical isolation

A physical incompatibility between reproductive organs of two organisms. It is a type of biotic barrier, where no fertilization occurs in thus reproduction does not occur. It includes any physical barrier that prevents mating.

gametic isolation

occurs when the two organisms/species mate successfully, but cannot form a zygote (prezygotic mechanism)

reduced hybrid viability

describes offspring that have a lower rate of survival than the parent species. This reduces the likelihood of the hybrid offspring surviving to sexual maturity.

reduced hybrid fertility

another type where the hybrid is viable, but is sterile, and cannot produce offspring

hybrid breakdown

A type of reproductive failure that appears after the F2 generation of crosses between different species or sub species. It is caused by incompatibility between interacting genes.

evidences of evolution

fossil record, comparative morphology, biogeography, and DNA/genetic information

Hardy-Weinberg equilibrium equation

p²+ 2pq + q² = 1
p²= percentage of homozygous dominant
2pq= percentage of heterozygous
q²= percentage of homozygous recessive

Hardy-Weinberg equilibrium equation 1

p = frequency of dominant allele

q = frequency of recessive allele