Exam 12: Earths Evolution Through Geologic Time

Fossil fuels are abundant in Precambrian rocks.

The ________ era is known as the "age of flowering plants."

In North America (including Greenland), the vast exposure of Precambrian rocks, called the ________ Shield, encompasses 2.8 million square miles.

Following the reptilian extinctions at the close of the Mesozoic, two groups of mammals, the marsupials and ________, evolved.

Fossils that are not of the animals themselves, but of their activities, such as trails and wormholes, are referred to as ________ fossils.

Examine Figure 12.13 below which illustrates the distribution of cratons and orogens (mountain belts) on Earth today. Briefly discuss how have these regions have developed over time using the concept of plate tectonics. Include the relationship between specific types of plate boundaries to the various regions if possible.

During the Cenozoic era, a great wedge of sediments from the eroding Rockies created the Great Plains.

As they formed, due to their high temperatures and comparatively weak gravitational fields, which planets were unable to retain appreciable amounts of hydrogen, helium, and ammonia?

The beginning of the Precambrian era is marked by the appearance of the first life forms with hard parts.

The process in which plants use light energy to synthesize food sugars from carbon dioxide is called ________.

The late ________ era extinction was the greatest of at least five mass extinctions to occur over the past 540 million years.

The most common Precambrian fossils are ________, layered mounds of calcium carbonate.

The first true terrestrial land animals were the mammals.

________ means "planets in the making."

Following the reptilian extinctions at the close of the Mesozoic era, two groups of mammals, the marsupials and ________, evolved and expanded.

During the ________ era, the westward-moving North American plate began to override the Pacific plate, eventually causing the tectonic activity that ultimately formed the mountains of western North America.

The ________ period was a time of major extinctions, including 75 percent of amphibian families.

The era of "ancient life" is the ________ era.

The Cenozoic era is the age of mammals.

The Cenozoic era is often called the "age of ________."