Exam 25: Evolutionary Processes

Two frog populations (same species)living in two neighboring lakes sing slightly different courtship songs.Predict what likely happens to the songs of the two frog populations after increased irrigation makes the land between the two lakes wetter.Females prefer loud frogs to quieter frogs,but do not distinguish between the two slightly different songs.Assume that courtship song differences have a genetic basis.

If an allele is found at a frequency of 0.8 in a population that is in Hardy-Weinberg equilibrium,and an individual is heterozygous for that allele,what is the probability they will pass on that allele to their offspring?

Figure 25.4 -This chapter's essay explains that the membrane protein involved in cystic fibrosis confers resistance to typhoid fever.Imagine that a drug-resistant form of typhoid fever becomes common worldwide,killing a significant proportion of the human population over a period of several decades.Which of the following would you expect to observe in the world population during this period?

The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid-1700s.They do not marry with members outside their own immediate community.Today,the Dunkers are genetically unique and differ in gene frequencies,at many loci,from all other populations including those in their original homeland.Which of the following likely explains the genetic uniqueness of this population?

Figure 25.4 -Male turkeys have a snood,a flap of skin that hangs across their beak.Snood length is negatively correlated with parasite load (e.g.,males with longer snoods have fewer parasites),and females prefer to mate with long-snooded males.This is an example of

The UCSD campus male junco population tails were,on average,36% white,whereas the tails of males from nearby mountain populations averaged 40-45% white.If this observed trait difference were due to a difference in the original colonizing population,it would be due to

Given the information about the number of individuals of specific genotypes in the table above,what can you infer?

Wikelski and Romero (2003)found that large marine iguanas had higher reproductive success than smaller iguanas did.However,the large iguanas were generally in poor body condition because they could not eat enough;at higher temperatures their foraging efficiency improved,allowing them to eat more.Thus,Wikelski and Romero hypothesize that iguana size will ________ as global warming gradually increases air and water temperatures in the Galápagos Islands.

A hurricane sweeps across the southern tip of Florida,killing salamanders randomly.Salamander colour is genetic,and,after the storm,scientists notice that the frequency of yellow-brown salamanders and green-brown salamanders has changed significantly.This is an example of a ________ and we would predict that 20 generations after the storm the population would show ________.

In Kerr and Wright's experiment with 96 fruit-fly populations,only 4 males and 4 females bred in each generation.After 16 generations,73% of their populations had only one allele present for the bristle morphology gene.Which of the following would you expect to occur if they allowed 10 males and 10 females to breed each in generation?

Figure 25.4 -Refer to Figure 25.4.Male reproductive success,measured as the number of offspring surviving to adulthood (pupating),is found for two closely related beetle species and graphed above.Which of these statements would you expect to be true of sexual dimorphism in the two species?

For biologists studying a large flatworm population in the lab,which Hardy-Weinberg condition is most difficult to meet?

In a population of parrots on an island,there is considerable variation in beak size.Parrots with small,thick beaks can efficiently eat locusts (insect),while birds with long,thin beaks can efficiently eat beetles.Both food types are available on the island.Which of the following types of selection,and effects on phenotypic variation would you expect to see?

Given the information above,what is the frequency of individuals with the A₁A₁ genotype?

The UCSD campus male junco population tails are about 36% white,whereas the tails of males from nearby mountain populations are about 40-45% white.The founding stock of UCSD birds was likely from the nearby mountain populations because some of those birds overwinter on the UCSD campus each year.Population sizes on the UCSD campus have been reasonably large,and there are significant habitat differences between the UCSD campus and the mountain coniferous forests;UCSD campus has a more open environment (making birds more visible)and a lower junco density (decreasing intraspecific competition)than that in the mountain forests.Given this information,which of the following evolutionary mechanisms do you think is most likely responsible for the difference between the UCSD and mountain populations?

An earthquake decimates a ground-squirrel population.The surviving population happens to have broader stripes on average than the initial population.If broadness of stripes is genetically determined,what effect has the ground-squirrel population experienced during the earthquake?

Which of the following is the most predictable outcome of increased gene flow between two populations?

Speller et al.(2010)analyzed turkey mitochondrial DNA haplotypes and reported that turkeys were domesticated by precontact native North American cultures in several independent events.Which of the following would be evidence of domestication of turkeys?

Martin Wikelski and L. Michael Romero (Body size, performance and fitness in Galápagos marine iguanas, Integrative and Comparative Biology 43 [2003]:376-86)measured the snout-to-vent (anus)length of Galápagos marine iguanas and observed the percent survival of different-sized animals. Figure 25.2 shows the log snout-vent length (SVL, a measure of overall body size)plotted against the percent survival of these different size classes for males and females. Figure 25.2 -Examine the figure above.What type of selection for body size appears to be occurring in these marine iguanas?

Suppose 64% of a remote mountain village can taste phenylthiocarbamide (PTC)and must therefore have at least one copy of the dominant PTC taster allele.If this population conforms to Hardy-Weinberg expectations for this gene,what percentage of the population must be heterozygous for this trait?