Chapter 13outlinept1

Chapter 13

Earth’s History Precambrian Time: Vast and

Puzzling

Precambrian History

• The Precambrian encompasses all the geologic time from 4.5 billion years ago until the state of the Cambrian Period, 4 billion years later.

• 88% of the geologic time scale is encompassed here.

Precambrian Rocks

• Many Precambrian rocks are buried under layers of younger rocks.

• Sometimes these rocks are exposed at the surface by the process of?

_________

• Most Precambrian rocks are igneous or metamorphic in nature and tend to form the core of most continents called _________

• The North American Continent was formed around the _________

Shield areas are rich in _________ such as nickel, iron, gold, silver, copper,

aluminum, uranium, and diamonds.

Earth’s Atmosphere Evolves

• Earth’s original atmosphere was composed of gases similar to those released by volcanic eruptions including:

• _________• _________• _________

• No oxygen

• As Earth cooled, water vapor condensed to form clouds and great rains began.

• Most of the rain evaporated before reaching the surface and when it did reach the surface it boiled or evaporated.

• The evaporation process caused the Earth to cool faster.

• The rain literally filled the ocean basins, which reduced the amount of water vapor in the air and reduced the amount of carbon dioxide, leaving a _________

rich atmosphere.

The Process of Change

• All organisms change• The study of changes that occur in

organisms is called the theory of ________.

• Are there evidences that tend to suggest this process occurs?

Evidence to support the theory of evolution

1. _________

only ___% of all living things were ever fossilized

3. Embryological Similarities

4. Vestigial Organs

• These are organs that you have that _________ function

• _________• _________• _________• _________• _________

Life through geologic time

• For the sake of this class, we will start in the Precambrian time.

• Why are fossils so rare to find from this time?

Most of the rocks are _________

Most critters here were without _________

What causes evolutionary changes to happen?

_________

Specialization•Some organisms tend to adapt toward _________ needs……

•What special needs do Koalas have ?

_________

Stress is……..

necessary to put _________ pressure on critters to make them change (_________ )

_________ means: _________

The more diversified the organism, the _________ its chances are to survive.

Examples how animals diversify

1. _________ex: _________2. _________ex: _________ _________ _________

Examples how animals diversify3.What animals can and

can not see color?Can not see color

____________________________________

__________________

_________

_________

Can see color____________________________________

Examples how animals diversify

4.Temperature

ex: _________ _________ _________ _________ _________

5. Ecotype adaptation

ex: _________ _________ __________________