Scientists who specialize in the study of fossils are called

• biologists.

• paleontologists.

• zoologists.

• geologists.

Sedimentary rocks usually form when layers of small particles are compressed

• in the atmosphere.

• in a snow field.

• in mountains.

• under water.

Using C–14 to analyze rock layers

• is a method of estimating absolute age.

• is a method of estimating relative age.

• can only be used on extremely ancient rock layers.

• is impossible because rock layers do not contain carbon.

Half-life is the time required for half the atoms in a radioactive sample to

• decay.

• double.

• expand.

• be created.

According to the theory of plate tectonics,

• Earth's climate has changed many times.

• Earth's continents move very slowly.

• evolution occurs at different rates.

• giant asteroids crashed into Earth in the past.

How does relative dating enable paleontologists to estimate a fossil's age?

Explain how radioactivity is used to date rocks.

What is the geologic time scale, and how was it developed?

How have the activities of organisms affected Earth's environment?

Calculate The half-life of carbon-14 is 5730 years. What is the age of a fossil containing 1/16 the amount of carbon-14 of living organisms? Explain your calculation.

Apply Concepts Evolutionary biologists say that there is a good reason for gaps in the fossil record. Can you explain why some extinct animals and plants were never fossilized?

The process that produces similar-looking structures in unrelated groups of organisms is

1. adaptive radiation.

2. coevolution.

3. convergent evolution.

4. mass extinction.

The general term for large-scale evolutionary changes that take place over long periods of time is called

1. macroevolution.

2. coevolution.

3. convergent evolution.

4. geologic time.

Cladograms that are based on the fossil record always show

1. which organisms are direct ancestors of the others.

2. relationships based on shared derived characteristics.

3. that clades are made up only of extinct species.

4. relative ages of organisms in the clade.

Explain and give an example of the process of adaptive radiation.

Explain the model of evolution known as punctuated equilibrium.

Use an example to explain the concept of coevolution.

Infer Major geologic changes often go hand in hand with mass extinctions. Why do you think this is true?

Apply Concepts Why is rapid evolution especially likely to occur in a small population that has been separated from the main population?

Apply Concepts What is the role of natural selection in adaptive radiation? How do these processes lead to diversity?