Exam 6: Evolution and Ecology

Refer to the figure. You are studying the evolution of a group of tree species that all share a common ancestor. -Referring to the figure, when might an adaptive radiation have occurred? Explain.

Genetic drift tends to _______ genetic variation within small populations, and _______ genetic differences among populations.

Refer to the figure. - The figure shows four cases of selection on egg number in a population of flour beetles. The solid blue line represents the frequency of the original population and the dashed red line represents the frequency distribution after eight generations. Which figure most likely represents a case of directional selection?

After large seeds became more common, the average beak size of the medium ground finch increased in size over the course of a few years. This change was most likely a case of

Refer to the figure. - The figure shows four cases of selection on egg number in a population of flour beetles. The solid blue line represents the frequency of the original population and the dashed red line represents the frequency distribution after eight generations. In which figure did the variance within the population for egg laying increase the most?

If an herbivorous beetle species is accidentally transported from China and becomes abundant and widespread in North America, which of the following statements is false?

Refer to the table. -Suppose that, following the experiments by Dodd, Drosophila pseudoobscura are fed one of two diets (starch or maltose) for many generations. Once they have adapted to the new food sources, individual females from the starch treatment are given a choice between a male adapted to starch (a starch male), or a male adapted to maltose (a maltose male). Once 50 females have chosen a mate, the experiment is repeated with females adapted to maltose. According to the results in the table, what percentage of starch females chose maltose males?

Refer to the figure. - The figure shows the changes associated with the overall size of bighorn sheep (top), and the size of their horns (bottom) during the period between 1975 and 2005. In 2005, the sheep had horns that were approximately _______ than the average horn lengths found in 1976.

Refer to the table. Suppose that, following the experiments by Dodd, Drosophila pseudoobscura are raised on one of two diets (starch or maltose) for many generations. Once they have adapted to the new food sources, individual females from the starch treatment are given a choice between a male adapted to starch (a starch male), or a male adapted to maltose (a maltose male). When 50 females have chosen a mate, the experiment is repeated with females adapted to maltose. The results are in the table. Which conclusion is best supported by the data?

Two tree species live in different environments yet share many similar characteristics. The most likely reason for these similarities is

Refer to the figure. You are studying the evolution of a group of tree species that all share a common ancestor. -Suppose that species B, C, E, and F all share characteristics that are very different from those of species D, but there are currently no living species that "fill the gap" between the B/C/E/F group and species D. Now suppose you could team up with a paleontologist to look for fossils to better understand how B/C/E/F became so different from species D. What age of rocks would you look for to target your search?

Refer to the figure. -Based on the figure, the largest mass extinction occurred about _______ million years ago.

In the 1890s, the biologist Hermon Bumpus found that sparrows that had survived a Rhode Island storm were more likely to be of intermediate size than sparrows that had perished from the storm. This is most likely an example of

Refer to the figure. - The figure shows four cases of selection on egg number in a population of flour beetles. The solid blue line represents the frequency of the original population and the dashed red line represents the frequency distribution after eight generations. Which figure most likely represents a case of disruptive selection?

Refer to the figure. Simulations, in which it was assumed that the populations were subject to only genetic drift (no selection), were performed using three different starting population sizes, and they were scored for the frequency of the B allele. All populations started with the frequency of 50% of the B allele. Each line represents a different replicate of the conditions. The three panels differ only in the population size. Which graph is of populations with the largest population size?

Suppose a population of shorthorn cattle has only two alleles (R and r) at a locus. If the frequency of R is 0.37, what is the frequency of r?

Refer to the figure. -You are studying a remote island before and after a volcanic eruption. Data at Time 1 were collected one month before the eruption, and data at Time 2 were collected one month after the eruption. All of the species on the island are endemic. The island is 100 km across. Each animal icon represents 20 individuals. Species A and B (the two snail species) generally move a distance of only 2 m a day. Species C (the bird) often covers 20 km a day in search of food. After the eruption, the lava flow hardens, and the island is divided by a 20-km strip of bare rock with few if any resources these animals need to survive. What is the most likely explanation for what happened to species A as a result of the volcanic eruption?

The recovery of egg hatching rates in the Illinois population of prairie chickens was most likely due to

Grasshoppers and crickets share many similar characteristics such as general body form, elongated hind legs (which they use for jumping), and particular wing structures. The simplest hypothesis that would explain the similarities between these insects is that they resulted from

Refer to the figure. -The figure shows the changes associated with the overall size of bighorn sheep (top), and the size of their horns (bottom) during the period between 1975 and 2005. In 2005 the sheep, on average, weighed approximately _______ than in 1976.