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It is created by the direct action of natural selection.
It arises in response to changes in the environment
It must be present in a population before natural selection can act upon the population.
It tends to be reduced by the processes involved when diploid organisms produce gametes.
A population that has a higher average heterozygosity has less genetic variation than one with a lower average
The population is diploid.
Heterozygotes can come about in two ways.
The population is doubling in number.
Heterozygotes have two alleles.
Change in allele or gene frequency
Change in gene expression
Change in average heterozygosity
Must happen, due to organisms’ innate desire to survive.
Must happen whenever a population is not well-adapted to its environment
Can happen whenever any of the conditions for Hardy-Weinberg equilibrium are not met.
Requires the operation of natural selection.
Requires that populations become better suited to their environments.
All of the above
Only A and B
It represents the result of selection for acquired characteristics.
It is synonymous with the process of gene flow.
It is descent of humans from present-day great apes
It is the differential survival and reproduction of the most-fit phenotypes.
Genetic variation among individuals
Variation among individuals caused by environmental factors
Three of the responses are correct
Two of the responses are correct
Mechanical . . . postzygotic
Behavioral . . . prezygotic
Mechanical . . . prezygotic
Temporal . . . prezygotic
Gametic . . . postzygotic
New mutations that occurred in the preceding generation.
Genetic drift due to the small size of the population.
Reshuffling of alleles in sexual reproduction.
Geographic variation within the population.
Reduced hybrid fertility
The formation of new species
The extinction of species
Dramatic biological changes, such as the origin of flight, within a taxon
The generation of biodiversity
A change in allele frequencies within the gene pool of a population
The postzygotic barrier called hybrid inviability
The postzygotic barrier called hybrid breakdown
The prezygotic barrier called hybrid sterility
The species is now extinct.
Speciation occurred instantaneously.
Speciation occurred in one generation.
Speciation occurred rapidly in geologic time.
The species will consequently have a relatively short existence, compared with other species
Occurs at such a slow pace that no one has ever observed the emergence of new species.
Occurs only by the accumulation of genetic change over vast expanses of time.
Must begin with the geographic isolation of a small, frontier population. must begin with the geographic isolation of a small, frontier population.
And microevolution are synonymous.
Can involve changes to a single gene.
The goal of natural selection is speciation.
When reunited, two allopatric populations will interbreed freely if speciation has occurred.
Natural selection chooses the reproductive barriers for populations.
Prezygotic reproductive barriers usually evolve before postzygotic barriers.
Speciation is a basis for understanding macroevolution.
The number of chromosomes in the gene pool must change.
Changes to centromere location or chromosome size must occur within the gene pool.
Large numbers of genes that affect a single phenotypic trait must change.
Large numbers of genes that affect numerous phenotypic traits must change.
At least one gene, affecting at least one phenotypic trait, must change.
A single diploid parent plant.
A single triploid parent plant.
Single tetraploid parent plant.
The hybridization of two parent species and subsequent chromosome duplications.
The hybridization of a diploid and a tetraploid parent species.
That evolution occurs.
A mechanism for how evolution occurs.
That Earth is older than a few thousand years.
A mechanism for evolution that was supported by evidence.
That population growth can outpace the growth of food resources.
The bottleneck effect
Less than they resembled animals on ecologically similar but distant islands
More than they resembled animals on ecologically similar but distant islands.
Less than they resembled animals in Europe.
Less than they resembled animals from Australia.
Very closely; in most cases, the species from the mainland and the islands were identical.
Darwin thought individuals varied
Darwin thought the Earth was a few thousand years old
Darwin thought fossils in a given area were similar to extant species in the same area
Darwin thought organisms were capable of producing many offspring
Darwin thought few offspring of a pair survived
They live in very different habitats.
They should share fewer homologous structures than two more closely related organisms.
Their chromosomes should be very similar.
They shared a common ancestor relatively recently.
They should be members of the same genus.
1 and 2
2 and 4
Inheritance of acquired characteristics
Differential reproductive success based on inherited characteristics
Inheritance of acquired characteristics
Change in response to need
A process of constant improvement, leading eventually to perfection
Survival of the fittest
The wing of a bat and the scales of a fish
The wing of a bat and the flipper of a whale
The antennae of an insect and the eyes of a bird
The feathers of a bird and the wing membrane of a bat
The wing of a bat and the wing of a butterfly
The bottleneck effect
The founder effect
There is heritable variation among individuals
Poorly adapted individuals never produce offspring
Species produce more offspring than the environment can support
Individuals whose characteristics are best suited to the environment generally leave more offspring than those whose characteristics are less well suited
Only a fraction of an individual’s offspring may survive
Technological innovation in agricultural practices will permit exponential growth of the human population into the foreseeable future.
Populations tend to increase at a faster rate than their food supply normally allows
Earth changed over the years through a series of catastrophic upheavals.
The environment is responsible for natural selection
Earth is more than 10,000 years old.
Genetic variation exists within populations
The best-adapted individuals tend to leave the most offspring
Individuals who survive longer tend to leave more offspring than those who die young
Populations tend to produce more individuals than the environment can support
Individuals adapt to their environments and, thereby, evolve
High rate of mutation
Bottle neck effect
Directional selection for extra toes