Download QAD Answers Time Marches On

Inside the Restless Earth
Chapter 3 Section 5
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A: The rock layers (strata) in the Grand
Canyon represent about 2 billion years of
Earth’s history.
◦ D:The Colorado River has cut (weathering and
erosion) the canyon in as much as 2km is some
areas.
◦ D: The river has been at work for almost 6 million
years.

A: Fossils of plants and animals are common
in the sedimentary rock structures of the
Green river in Colorado, Utah, and Wyoming.
◦ D: The rocks were part of a system of lakes for
millions of years.
◦ D: Fine-grain sediment preserved delicate
structures

A: The geologic time scale in divided into
eons, eras, periods, epochs.
◦ D: eon
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Hadean (4.6 billion – 3.8 billion year ago)
Archean (3.8 billion – 2.5 billion years ago)
Proterozoic (2.5 billion - 543 million years ago)
Phanerozoic (543 million – present time)
◦ D: Panerozoic eon is divided into three eras
 Cenozoic
 Mesozoic
 Paleozoic

A: Throughout history the number of
different species either increased or
decreased.
◦ Hallucigenia appeared in the Cambrian period
◦ Other organisms disappeared
 Extinction-the death of every member of a species (ex.
Dinosaurs)

A: This is the first era represented by fossils
and is known as the old life era.
◦ D: Marine (ocean) life flourished
◦ D: Near the end of the era-reptiles began to live on
land
◦ D: This era ended with a mass extinction. 90% of
all species were killed

A: This is called the age of reptiles because
dinosaurs roamed the land during this time.
◦ Birds and mammals began to evolve
◦ 15%-20% of species went extinct
 Climate change or an asteroid caused the extinction

A: This era is known as the Age of Mammals.
◦ D: Mammals flourished
 Regulate body temperature