Biology Questions
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Early in the third month, ectodermal epithelium of forming meatus proliferates and form meatal plug (a solid mass of epithelial cells). Later, a channel within meatal plug extends existing external auditory meatus to the level of tympanic membrane
the process by which a sperm and an egg are united is called
16. An oak tree produces two kinds of leaves: large with shallow lobes, and narrow with deep lobes. If thisdimorphism is based solely on the ecological condition of amount of sunlight exposure and no genetic differenceexists between leaves that express either of the two forms, then:A) natural selection cannot preferentially select one of the two leaf forms over the other.B) the environment cannot affect the relative abundance of the two leaf forms.C) this must be a trait that expresses quantitative variation.D) natural selection cannot act on the trait of leaf morphology.E) the large, shallow-lobed leaves must be adapted for sunnier conditions
One end of semicircular duct forms dilation (Crus Ampullare), the other does not widen (Crus nonampulare)As two of the crus nonampullare will fuse together, there will be 3 crus ampullare and 2 crus nonampullare
depolarization of an egg following fertilization prevents more than one sperm from entering the egg, a condition called
18. Which of these is not a mechanism of genetic change in populations?A) mutationB) migrationC) genetic driftD) natural selectionE) heritability
23. The contribution of a genotype or phenotype to the genetic composition of subsequent generations relative toother genotypes or phenotypes best describes which of the following concepts?A) evolutionB) migrationC) the founder effectD) fitnessE) natural selection
It separates from surface ectodermElongation of it forms a dorsal vestibular region and a ventral cochlear region
14. Genetic drift will have the greatest effect for populations:A) that are in Hardy-Weinberg equilibrium.B) that are undergoing stabilizing selection.C) that are undergoing directional selection.D) with a high degree of gene exchange with other populations.E) that are very small.
24. Evolutionary change as a result of natural selection:A) always leads to increased complexity.B) inevitably leads to malfunction.C) always leads to more intricate adaptations.D) trends toward uniformity.E) never leads to perfect organisms.
On day 22, otic placode (thickened surface ectoderm) is formed on each side of hindbrainOtic vesicle (otocyst) is formed by invagination of otic placode
21. To establish that evolution by natural selection is operating in a population, one must demonstrate variability fora trait, heritability, and which of the following?A) progressB) differential reproductive successC) increased complexity of an organismD) random matingE) continuous change in the environment
13. A storm washed five female and five male tiger beetles from the mainland to a small island that had no previouspopulation of tiger beetles. In tiger beetles, having six spots (A) is dominant to having four spots (a). All ten beetleshad six spots; however, one male and one female were heterozygous for the four-spot trait. If six of the beetles diedwithout reproducing, the ratio of the genotypes could be quite different in subsequent generations. This is anexample of:A) diploidy.B) gene flow.C) genetic drift.D) disruptive selection.E) stabilizing selection.
19. Which scenario is the most likely to result in natural selection that leads to adaptive evolution in a population ofhumans?A) Individuals in Australia only reproduce by random mating.B) Individuals colonize another planet and become isolated from earth.C) A tsunami kills hundreds of thousands of people in Southeast Asia.D) A new influenza strain becomes an epidemic and kills all individuals over age 50.E) Mortality due to heart disease increases to 80% in middle-aged Americans.
22. Which characteristic would not increase or decrease the fitness of the organisms that possess it?A) Certain fruit flies in a population carry genes that increase their ability to survive longer without food thanindividuals that do not possess that gene.B) Certain mice in a population carry genes that cause their fur to be darker than the fur of other individuals that donot possess those genes.C) Certain male birds in a population carry genes that increase the size of their tail relative to the size of the tails ofthe male individuals that do not possess those genes.D) Certain sterile mules in a population carry genes that allow them to carry heavier loads than other sterileindividuals that do not possess those genes.E) Certain humans in a population carry genes that cause their eyesight to deteriorate at a more rapid rate thanother individuals who do not possess those genes.
38. The larvae of the gooseneck barnacle and brine shrimp display similar morphological features, despitedifferences observed in the adult forms. The similarities present in the larval forms suggest that:A) evolution was "descent with modification."B) the results of evolution could be viewed as a "tree of life."C) similarities among embryos can infer relationships between species.D) changes in genes regulate the development of organisms.E) the genes that regulate development are highly conserved.
30. Directional selection favors:A) one narrow intermediate phenotype.B) two otherwise maladapted phenotypes.C) one broad intermediate phenotype.D) one extreme phenotype.E) two extreme phenotypes.
10. Genetic drift leads to fixation when an allele's frequency reaches _____ in a population.A) 1%B) 10%C) 50%D) 51%E) 100%
32. Assume that you find a population of finches in which the members have a bimodal distribution in bill size. Someindividuals have a significantly larger bill than others, regardless of sex. Under which condition could disruptiveselection maintain this bimodal distribution of bill size?A) The population has two major food sources that differ markedly in size.B) Bills of the intermediate size are difficult to form.C) In the original population, all of the birds had large bills, but there is continual immigration of birds with small billsinto the population.D) Males use their bills in two different forms of sexual display.E) Directional selection cannot act on bill size.
11. If a gene is fixed in a population:A) it cannot undergo mutation.B) one allele exhibits complete dominance over the other allele for that gene.C) only one allele appears for that gene in that population.D) it causes the organism to be infertile.E) it is located near the centromere on the chromosome, reducing its ability to recombine.