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Ch. 17
The Means of Evolution
| Question | Answer |
|---|---|
| What is adaptation? | A modification in the form, physical functioning, or behavior of organisms in a population over generations in response to environmental change. |
| What is an allele? | One of the alternative forms of a single gene. In pea plants, a single gene codes for seed color and it comes in two _____-one codes for yellow seeds, the other for green seeds. |
| What is a bottleneck effect? | A change in allele frequencies in a population due to chance following a sharp reduction in the population's size. One of the factors that potentiates genetic drift. |
| What is directional selection? | In evolution, the type of natural selection that moves a character toward one of its extremes. Compare to stabilizing and disruptive selection. |
| What is disruptive selection? | In evolution, the type of natural selection that moves a character toward both of its extremes, operating against individuals that are average for that character. This type is less common in nature than either stabilizing or directional selection. |
| What is evolution? | Any genetically based phenotypic change in a population of organisms over successive generations. Species of living things can undergo modification over successive generations, with such modifications sometimes resulting in formation of new species. |
| what is fitness? | In evolution, the success of an organism, relative to other members of its population, in passing on its genes to the next generation of offspring. |
| What is the founder effect? | The phenomenon by which an initial gene pool for a population is established by means of that population migrating to a new area. One of the conditions that potentiates genetic drift. |
| What is gene flow? | The movement of genes from one population to another. |
| What is a gene pool? | The entire collection of alleles, or variant forms of genes, in a population. |
| What is genetic drift? | The chance alteration of allele frequencies in a population, with such alterations having greatest impact on small populations. |
| What is a genotype? | The genetic makeup of an organism, including all the genes that lie along its chromosomes. |
| What is macroevolution? | Evolution that results in the formation of new species or other large groupings of living things. |
| What is microevolution? | A change of allele frequencies in a population over a short period of time. The basis for all large-scale evolution (macroevolution). |
| What is migration? | The movement of individuals from one population into the territory of another. |
| What is natural selection? | The process through which traits that confer a reproductive advantage to individual organisms grow more common in populations of organisms over successive generations. |
| What is a phenotype? | A physiological feature, bodily characteristic, or behavior of an organism. |
| What is polygenic? | Having multiple genes affecting a given character, such as height in humans. |
| What is a population? | All the members of a species that live in a defined geographic region at a given time. |
| What is sexual selection? | A form of natural selection that produces differential reproductive success based on differential success in obtaining mating partners. |
| What are species? | A group of actually or potentially interbreeding natural populations that are reproductively isolated from other such populations. |
| What is stabilizing selection? | In evolution, the type of natural selection in which intermediate forms of a given character are favored over either extreme. This process tends to maintain average traits for a character. Compare to directional and disruptive selection. |
| In most populations of living things, each individual has ___ copies of each gene, which may be the same or different allelic variants. A population may have ____ allelic variants for a given gene. | 2; many |
| What are the meanings of: A.) gene pool B.) allele C.) allele frequency D.) genotype E.) gene flow | A. the set of all alleles in a population; B. a variant form of a gene C. The relative representation of a given form of a gene in a population D. the genetic makeup of an organism E. exchange of genes between populations |
| What is a true statement about microveolution? | It is a change in allele frequency within populations. |
| Agents of allele frequency change in populations include: A.) genetic drift B.) meiosis C.) mutation D.) segregation E.) natural selection | Genetic drift, mutation, and natural selection |
| Agents that consistently produce adaptive evolution (adaptation) include: A.) genetic drift B.) mutation C.) meiosis D.) natural selection E.) gene flow | Natural selection |
| Mutations are: A.) generally beneficial B.) sometimes heritable C.) always caused by changes in single base pairs of DNA D.) the ultimate source of new genetic information E.) prone to occur with great frequency | B. sometimes heritable D. the ultimate source of new genetic information |
| What are the descriptions of: A.) mutation B.) gene flow C.) natural selection | A. changes in the genetic material B. movement of alleles between populations by migration c. a process through which traits that confer a reproductive advantage to individuals are seen with greater frequency in succeeding generations of a population |
| What are the descriptions of: A. genetic drift B. founder effect | A. the genetic makeup of an organism B. the exchange of genes between populations |
| Finches in the Galapagos experienced ______ selection on beak depth following a drought; the African finch P. ostrinus experienced _____ selection on beak size because it eats either very small, soft seeds or much larger, hard seeds | directional; disruptive |
| The essential unit that evolves in nature is the _____, which can be defined as all the members of a _____ ______ living in a specific geographic region at a given time. | population; single species |
| Genes come in variant forms called ______. A gene pool is defined as all the ______ that exist in a ______. | alleles; alleles; population |
| Microevolution is defined as a change in ______ ______ in a population over a relatively short period of time. | allele frequencies |
| What the agents of microevolution all have in common is that each of them can alter _______ ________ in a population. | allele frequencies |
| Genetic drift is a _____ alteration of ______ ______ in a population that has its greatest effect on ______ populations. | chance; allele frequencies; small |
| In sexual selection, differential reproductive success comes about because of differential success in obtaining _______ ________. | mating partners |
| True or False: If an insect has 1,000 offspring, we can label it as "fit" in an evolutionary sense. | False: Evolutionary fitness exists only in a relative sense; in a population, one organism is more or less fit than another depending on whether it has more or fewer offspring than another. |
| In stabilizing selection, forms that are ____ are favored over forms that are _____. | intermediate; extreme |
| We normally think of evolution working through _____ _______, in which a character moves toward _______ _______. | directional selection; one extreme |
Created by:
kpalmerton
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