Biology 18, 19, 20

Hawaiian honeycreepers are a group of birds with similar body shapes and size. However they vary greatly in color and beak shape. Each species occupies its own niche and is adapted to the foods available in its niche. Which type of evolution is this en example of?

divergent evolution

If an allele makes up one fourth of a population's alleles for a given trait, its relative frequency is

25%

Which is MOST likely to be explained by the concept of coevolution?

Markings on flower petals attract bees that pollinate the flower.

Two species of fruit flies whose ranges overlap have different periods of mating activity. Drosophila persimilis breeds early in the morning, while Drosophila pseudoobsura breeds in the afternoon. Identify the mechanism of isolation between these two species.

Temporal isolation: The species remain separate because the period of most active mating differs.

According to the Hardy-Weinberg principle, the frequencies of alleles remain constant in a population, but only under certain conditions. Which of these events or conditions is most likely to maintain Hardy-Weinberg equilibrium?

The alleles have no effect on which males and females mate and produce offspring.

A plant called a heliconia has flower parts that form an unusual curved shape. Vera claims that the evolution of the flower shape is an example of coevolution. Which of the following observations would provide the STRONGEST evidence in support of Vera's claim?

The beak of a species of hummingbird fits snugly into the curved flower parts of the heliconia.

The cladogram shown represents the evolutionary relationship among five modern species, as well as five derived characters of the lineages. Although derived characters may be lost, none of the derived characters shown in the cladogram were lost in the five modern species. Identify the choice that best completes the statement or answers the question. Which statement describes the evolution of the trait of an amniotic egg?

The trait evolved in an ancient ancestor of lizards and wallabies, and was passed to all of the ancestor's descendants.

The domain is a relatively new taxonomic category. Why did scientists add the domain to the Linnaean classification system?

The two groups of prokaryotes differ greatly from each other and from eukaryotes.

In the Linnaean system of classification, camels are members of the order Artiodactyla and the family Camilidae. Llamas are also members of the family Camilidae. Based on this information, are llamas members of the order Artiodactyla?

Yes, because all family members are classified together in the same order.

All the genes of all members of a particular population make up the population's

gene pool

The two main sources of genetic variation are

gene shuffling and mutations

Which is an example of evolution by genetic drift, and NOT by natural selection?

A small population of bark beetles is carried in driftwood to a new island, where the members reproduce rapidly.

A geneticist collected data of a population of mice. Of the 50 mice, 12 were homozygous black (BB), 24 were heterozygous black (Bb), and 14 were brown (bb). What are the allele frequencies for the (B) and (b) alleles in this population?

B = 0.48; b = 0.52

A scientist is studying the classification of three species of birds, labeled Bird A, Bird B, and Bird C. According to a field guide on birds, Birds A and B are very closely related, while Bird C is a more distant relative. However, the scientist concludes that the field guide is wrong, and that Birds A and C are the closest pair of relatives. Which finding would provide the STRONGEST evidence in support of the scientist's conclusion?

Birds A and C share more genetically derived characters with one another than with Bird B.

In a population of goats, both beige-coated and brown-coated goats are better able to blend with the rocky environment than white-coated goats. In this case, the beige and brown coat colors are favored by natural selection over the white color. Which type of pattern of natural selection would occur in this scenario?

Disruptive Selection

Which is an example of binomial nomenclature in the Linnaean system of taxonomy?

Felis catus

Over the past 80 years, changes have occurred to the bacteria populations that commonly cause infectious diseases. The drug penicillin once killed most of these bacteria. Now, the original form of penicillin kills a very low percentage of the bacteria population. How does evolution by natural selection explain this change to the bacteria population?

Repeated us of penicillin selected for bacteria that were resistant to it; these bacteria passed resistance to the next generation

Western and Eastern meadowlarks look very similar and it is difficult to tell them apart, until they sing. Their mating songs are quite different. The Western meadowlark has a melodious song, whereas the song of the Eastern meadowlark sounds more like a whistle. Even though their ranges overlap in the central United States, they do not interbreed and are two different species. How would speciation most likely have occurred in these two species of meadowlarks?

Reproductive isolation occurred through behavioral isolation.

A team of scientists discovers a fossil of an ancient plant species. They report that the plant developed from an embryo and had vascular tissues, but it did not have seeds. The ancient plant might have been an ancestor of which set of plants?

Something between embryo and seeds on the a cladogram

Robins typically lay four eggs. Four eggs allow the offspring to be well fed, whereas larger clutches may result in malnourished chicks that have a lower chance of survival. Fewer than four eggs per clutch may result in no surviving offspring if the eggs are preyed upon. Which pattern of natural selection most likely acts to keep four eggs the most common clutch size?

Stabilizing selection

A population of mice lives on an island in the Pacific Ocean. From year to year, the size of the adult population remains at about 300 individuals, and the variety and frequency of the genes and alleles of the mice change very little. What events would be MOST likely to cause a change to the allele distribution of the mouse population on the island?

a drought that reduced and altered the food supply of the mice

The genetic equilibrium of a population will not be disturbed by

a large population size

According to one scientific study, the ancient ancestor of all placental mammals was about the size of a shrew or rat. It climbed trees and ate insects. It evolved soon after the mass extinction that killed the dinosaurs. As shown by the cladogram, several classes of mammals evolved from the common mammal ancestor. Each line in the diagram represents an evolutionary lineage. The cladogram above describes an example of which macroevolutionary pattern, and for what reason?

adaptive radiation, because an ancient ancestor gave rise to many species with diverse adaptations

In genetic drift, allele frequencies change because of

chance

The flying squirrel of North America very closely resembles the flying sugar glider of Australia. They are similar in size, have long, bushy tails, and thin folds that allow them to glide through the air. The squirrel is a placental mammal while the sugar glider is a marsupial. These close resemblances, even though genetically geographically separated by great distances, can best be explained by:

convergent evolution

The type of genetic drift that follows the colonization of a new habitat by a small group of individuals is called

the founder effect

A scientist is studying the fossil record to construct an evolutionary lineage for an order of fishes. The scientist proposes that the lineage involves long periods of little change to species, then brief periods of significant changes. Is the scientist's proposal consistent with modern evolutionary theory?

yes, the scientist is describing a pattern of punctuated equilibrium