Exam 12: Earths Evolution Through Geologic Time

The major source of oxygen in Earth's atmosphere is from the decay of plants.

The age of Earth is about ________.

The time of the great extinction that took place at the end of the Mesozoic era is called the ________ or KT boundary.

Due to a virtual absence of land plants and certain animals, fossil fuels are notably absent in ________ rocks.

Each continent contains large "core areas" of Precambrian rocks referred to as ________.

Bacteria that thrive in oxygen free environments are called ________ bacteria.

During the ________ period, large evaporite deposits of rock salt and gypsum formed in North America.

One hypothesis for the extinction that took place at the end of the Mesozoic is that a large ________ collided with Earth.

Toward the end of the Mesozoic era, the ________ orogeny formed the southern ranges of the Rocky Mountains.

The ________ means "the Sun in the making."

During the early Paleozoic era, the ________ orogeny affected eastern North America from the present-day central Appalachians to Newfoundland.

Volcanic activity was common in western North America during much of Cenozoic time.

This least understood era of Earth's history has not been subdivided into briefer time units.

Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.

Abundant fossil evidence did not appear in the geologic record until about ________.

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

Western North America is the leading edge of the ________ plate.

Earth's primitive atmosphere evolved from gases ________.

The most common Precambrian rock type is ________ rock.

The theory for the formation of the solar system is known as the ________.