Chapter 7 Review

The earliest form of life known on Earth was:

• leafy plants

• bacteria

• fossils

• single-celled organisms

During the Paleozoic Era, the first organisms to live partly on land were:

• insects

• reptiles

• amphibians

• invertebrates

Which best describes the climates of Europe and North America during the 1.8 million years of the Quaternary Period?

• hot and dry climates

• cool and rainy periods followed by droughts

• warm and mild climates

• a series of ice ages followed by periods when the glaciers melted

What has the study of fossils allowed scientists to do?

• describe past environments and the history of life

• study present ocean temperatures at different depths

• analyze the chemical composition of sedimentary rocks and minerals

• predict which organisms will become extinct in the future

Which era was known a the, "Age of the Reptiles"?

• Mesozioc

• Cenozoic

• Paleozoic

• Precambrian

According to scientists, both Earth and the moon are...

• about 1.6 billion years old

• about 4.6 billion years old

• about 9.6 billion years old

• about 14 billion years old

The relative age of a rock is

• its age compared with the ages of other rocks

• less than the age of the fossils the rock contains

• the number of years since the rock has formed

• its age based on how much carbon-14 the rock contains

Geologists use radioactive dating to

• determine the relative ages of rock layers

• tell the difference between molds and casts

• tell where one soil horizon ends and the next one begins

• determine the absolute age of rocks

What are fossils?

• molds and casts of organisms that live today

• drawings of ancient animals and other organisms

• footprints or burrows of small animals that live today

• the preserved remains or traces of organisms that lived in the past

Originally, the geologic time scale placed Earth's rocks in order by

• absolute dates

• relative age

• composition

• decades and centuries