Exam 19: Earths Evolution Through Geologic Time

Western North America is the leading edge of the _________plate.

During the early Paleozoic era, the current continents of South America, Africa, Australia, Antarctica, India, and perhaps China comprised the vast southern continent of __________.

The Cenozoic Era is often called the "age of _________."

Towards the end of the Mesozoic Era, the_________ Orogeny formed the southern ranges of the Rocky Mountains.

During the Cenozoic, plate interactions gave rise to many events of mountain building, volcanism, and earthquakes in _________North America.

Bacteria that thrive in oxygen free environments are called_________ bacteria.

One group of reptiles, exemplified by the fossil Archaeopteryx, led to the evolution of __________ .

Why is it so difficult to interpret the geology of the Precambrian? How are these difficulties or limitations different in the younger eras of the Phanerozoic Eon? Finally, are there unique rocks or events in the Precambrian that are not present in younger rocks?

The _________Period was the "golden age of trilobites."

The rock formations of the __________ Era are more widespread and less disturbed than those of any other time.

_________Eon accounts for ~90% of the geologic time scale.

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

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

The major source of free oxygen in the atmosphere is from_________ .

What were the three gases that made up Earth's original atmosphere?

Many of the most ancient fossils are found in a hard, dense, chemical rock called_________ _.

_________are the dominant land plants of the Cenozoic Era.

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?

Which of the following gases was not part of Earth's original atmosphere?

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