Exam 25: The History of Life on Earth

You are the lucky student of a wacky professor who develops a time machine. He asks if you will test it with him. You get in, and there is an immediate glitch-the date readout fails so that when you land, you are not sure what era you are in. Your professor begins to panic, but you see something that tells you are in the Cenozoic era. Which of the following could it be?

Insect wings may have begun to evolve as lateral extensions of the body that were used as heat dissipaters for thermoregulation. When they had become sufficiently large, these extensions became useful for gliding through the air. Additional selection refined them as flight-producing wings. If this hypothesis is correct, modern insect wings would be an example of ________.

Which listing of geological periods is in the correct order, from oldest to most recent?

Adaptive radiations can be a direct consequence of three of the following four factors. Select the exception.

Many species of snakes lay eggs. However, in the forests of northern Minnesota, where growing seasons are short, only live-bearing snake species are present. This trend toward species that have live births in a particular environment is an example of ________.

Which of the following is a limit of evolution that results in exaptations?

How was early Earth from more than three billion years ago different from today's Earth? Unlike Earth today, early Earth ________.

Which of the following statements suggests natural selection as a mechanism in the evolution of ribozymes?

Which period had the greatest increase in the number of extant species?

How does continental drift explain the uniqueness of Australian fauna?

Why are fossils considered to be an incomplete record of evolution?

The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic effects of Pitx1 gene ________.

Which of the following characteristics are expected in the first animals to have colonised land? I. They were probably herbivores (ate photosynthesisers). II. Animals had four appendages. III. Animals had the ability to resist dehydration. IV. Animals had lobe-finned fishes as ancestors. V. Invertebrates

Which of the following would be least likely to appear in the fossil record?

An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to ________.

The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that ________.

The oxygen revolution changed Earth's environment dramatically. Which of the following took advantage of the presence of free oxygen in the oceans and atmosphere?

What is true of the Cambrian explosion?

If a fossil is encased in a stratum of sedimentary rock without any strata of volcanic rock (for example, lava or ash) nearby, then it should be ________.