CHAPTER 16 Test Your Knowledge

Driving Question 1

By answering the questions below and studying Infographics 16.1, 16.2, and 16.3, you should be able to generate an answer for the broader Driving Question above.

KNOW IT

Which of the following is most likely to leave a fossil? a. a jellyfish

b. a worm

c. a wolf

d. a sea sponge (an organism that lacks a skeleton)

e. All of the above are equally likely to leave a fossil.

Generally speaking, if you are looking at layers of rock, at what level would you expect to find the newest—that is, the youngest—fossils?

You are examining a column of soil that contains vertebrate fossils from deeper to shallower layers. Would you expect a fossil with four limbs with digits to occur higher or lower in the soil column relative to a “standard” fish? Explain your answer.

What can the fossil shown below tell us about the structure and lifestyle of the organism that left it? Describe your observations.

USE IT

You have molecular evidence that leads you to hypothesize that a particular group of soft-bodied sea cucumbers evolved at a certain time. You have found a fossil bed with many hard-shelled mollusks dating to the critical time, but no fossil evidence to support your hypothesis about the sea cucumbers. Does this find cause you to reject your hypothesis? Why or why not?

A specific type of oyster is found in North American fossil beds dated to 100 million years ago. If similar oyster fossils are found in European rock, in layers along with a novel type of barnacle fossil, what can be concluded about the age of the barnacles? Explain your answer.

Driving Question 2

By answering the questions below and studying Infographics 16.4 and 16.5, you should be able to generate an answer for the broader Driving Question above.

KNOW IT

Which of the following features of Tiktaalik is not shared with other bony fishes? a. scales

b. teeth

c. a mobile neck

d. fins

e. none of the above

Tiktaalik fossils have both fishlike and tetrapod-like characteristics. Which characteristics are related to supporting the body out of the water?

USE IT

Tiktaalik fossils are described as “intermediate” or “transitional” fossils. What does this mean? Why are transitional organisms so significant in the history of life?

Tiktaalik has been called a “fishapod”—part fish, part tetrapod. Speculate on the fossil appearance of its first true tetrapod descendant—what features would distinguish it from Titkaalik? How old would you expect those fossils to be relative to Titkaalik?

If some fish acquired modifications that allowed them to be successful on land, why didn’t fish just disappear? In other words, why are there still plenty of fish in the sea if the land presented so many favorable opportunities?

Driving Question 3

By answering the questions below and studying Infographics 16.5, 16.6, and 16.7, you should be able to generate an answer for the broader Driving Question above.

KNOW IT

Compare and contrast the structure and function of an eagle wing with the structure and function of a human arm.

Vertebrate embryos have structures called pharyngeal pouches. What do these structures develop into in an adult human? In an adult bony fish?

You have three sequences of a given gene from three different organisms. How could you determine how closely the three organisms are related?

USE IT

What is the evolutionary explanation for the fact that both human hands and otter paws have five digits?

Could you use the presence of a tail to distinguish a human embryo from a chicken embryo? Why or why not?

If, in humans, the DNA sequence TTTCTAGGAATA encodes the amino acid sequence phenylalanine-leucine-glycine-isoleucine, what amino acid sequence will that same DNA sequence specify in bacteria?

Gene X is present in yeast and in sea urchins. Both produce protein X, but the yeast protein is slightly different from the sea urchin protein. What explains this difference? How might you use this information to judge whether humans are closer evolutionarily to yeast or to sea urchins?