Exam 15: Tracing Evolutionary History

You compare homologous nucleotide sequences among several pairs of species with known divergence times. A pair of species that diverged 1 million years ago has two nucleotide differences, a pair that diverged 2 million years ago has four nucleotide differences, and a pair that diverged 3 million years ago has six nucleotide differences. You have sequence data for another pair of species for which the divergence time is unknown. There are five nucleotide differences between them. Based on your clock, when did their line of ancestry diverge?

The "big bang" that produced the universe is thought to have occurred

The Mesozoic era is often called the age of reptiles. Which of the following also occurred during this era?

Miller-type experiments have shown that

How is the merging of continents to form Pangaea believed to have altered Earth's environments at the end of the Paleozoic era?

In the three-domain system, the eukaryotes are represented

The similarities in function of hummingbird wings and the wings of a butterfly reflect

Feathers are an example of a/an ________; they originally evolved ________.

Which of the following is an example of exaptation?

Over a span of several thousand years, a number of species show adaptations to climate change: Drier, warmer conditions select for succulent vegetation and deep taproots in plants, burrowing in mammals and amphibians, and other similar adaptive changes. What will happen if the climate shifts in the opposite direction and becomes progressively wetter and cooler?

Which of the following statements regarding genetics is false?

The greatest number of organisms would be found in

________ makes it possible to trace phylogenies among microbial groups for which there is no fossil record.

How can a phylogenetic tree be used to make predictions?

The three-domain system

According to this figure, during what time frame was there an adaptive radiation of eutherians?

If all of Earth's history were compressed into an hour, humans would first appear less than

Anti-evolutionary thinkers sometimes argue that natural selection could not produce a complex structure like the vertebrate eye. They claim that all of the parts of the eye must have arisen at once, asking why natural selection would favor the development of part of an eye that is not yet capable of forming a focused image. Which of the following statements is consistent with a survey of eye structure in the molluscs?

How can the success of one group of organisms promote the adaptive radiation of a second group?

In 1865, a biologist, St. George Jackson Mivart, constructed an evolutionary tree of existing primate species with many branches based on analysis of spinal columns. But to his dismay, another tree based on limb comparison was quite different. Which of the following analyses would be best to include today to determine which tree is more accurate?