Unit Test Answers

Why do a chicken embryo and a cow embryo look very similar even though the adults do not?

Variations within a species are an important part of Charles Darwin's theory of evolution. Which example can be explained by individual variation?

Darwin’s finches evolved on an island. What is the main reason that islands often provide good examples of evolution?

Carlos is collecting data about the length of earthworms in his backyard. The shortest worm he found is 4 inches long; the longest worm is 8 inches long. If most of the worms are either short or long, which type of distribution is displayed in the population?

Consider the cladogram.Which is the best description of the two organisms highlighted in orange?

Which is an example of temporal isolation?

Consider the cladogram.According to the cladogram, which characteristic was used to separate bony fish from amphibians?

Consider the generalized cladogram of fish.Osteichthyes is a group of fish that have the derived characteristics of jaws and true bones. Which letter corresponds to where Osteichthyes belongs on the cladogram?

Populations of organisms that exhibit a high degree of variation have a greater chance for survival than populations of organisms that show little variation. This statement is

Changes in the gene pool can occur due to various mechanisms. In 1989, a large oil spill occurred in Prince William Sound, Alaska, when the Exxon Valdez oil tanker ran aground. Approximately 11 million gallons of oil were spilled and spread 1,300 miles along the Alaskan coastline. The damage from the oil spill affected thousands of animals in the area, including killer whales, harbor seals, sea otters, fish, and sea birds. Which mechanism most likely affected the gene pools of the organism populations in the areas around the oil spill?

Read this passage about global fishing.Global consumption of large fish has led to an exploitation of fish populations. Overfishing has led to a decline in the populations of many species of large fish including North East Arctic Cod. The graph below shows the decline in the cod population.As the human population grows and countries continue to develop, the demand for large fish has been steadily increasing. Unfortunately, the average size of the cod has decreased because the fishing nets were designed to catch the large fish and the smaller individuals could escape more easily.What is most likely happening to the genetic variation of the population of North East Arctic Cod?

Read the following passage from the Biology Department at University of California, Berkeley.Northern elephant seals have reduced genetic variation because hunting by humans reduced their population size to as few as 20 individuals at the end of the 19th century. Their population has since rebounded to over 30,000, but their genes still carry the marks of this near extinction: they have much less genetic variation than a population of southern elephant seals that was not hunted as intensely.Which of the following best describes how the population has evolved?

It can be seen on a cladogram that modern birds and reptiles share a common ancestor. Select the piece of evidence that best supports this idea.

A feature in the early hominid was her apelike shoulders and forelimbs, but a pelvis that indicated that most of her body weight lay above her pelvis. Which best describes the fossil?

What will happen to the frequency of the recessive allele for the HbS gene when there is an outbreak of malaria?