Download This History of Life

Where
did we come
from?
How did the Earth
created or come to be?
Big Bang theory
 Creation

 Big
Bang - The Big Bang Theory is the
dominant scientific theory about the
origin of the universe. According to
the big bang, the universe was
created sometime between 10 billion
and 20 billion years ago from a
cosmic explosion that hurled matter
and in all directions

Divine origin - (Earth
and life was not
spontaneous and
placed here by
creator)
4.6 billion years old (radiometric dating)
 Current population 7,206,766,000
 261 born every minute
 Year 1000 = 310 million (current US pop.)
 1900 = 1.6 billion
 2050 = 9 billion
 Life first appeared on Earth between 3.9
– 3.5 billion years ago.

Earth was one big ball of magma
 Meteorites hit the Earth causing heat
 Volcanoes emit gases creating
atmosphere (H20, CO2, S02, CO, H2S,
HCN, N2, H2)

http://www.youtube.com/watc
h?v=Tz8ithgTBj4
Earth cooled and water formed oceans
 500 millions of years ago, life first
appeared
 Earliest clues date 3.5 billion years ago
 Records in fossils: Trace, Molds/Casts,
Replacement, Petrified, Amber, Original
material)


In 1915, a geologist named Alfred
Wagner came up the theory of
Continental drift. This theory states that
parts of the Earth's crust slowly drift atop
a liquid core. Fossils records found,
support the theory of continental drift
and plate tectonics. Pangea started as
one big super continent then during the
Jurassic period broke up into two smaller
super continents.
Model that expresses the major
geological and biological events in
Earth’s history.
 Divided into Precambrian and
Phanerozoic eon.
 Era – next largest division
 Period – each era divided into one or
more periods

What happened to them?
 Theories:

› Volcanism
› Plate tectonics (earthquakes)
› Disease
› Alvarez Asteroid Theory (The asteroid hit the
Earth. Research found a likely candidate for the
crater at Chicxulub, on the Yucatan Peninsula of
Mexico.)
› http://www.youtube.com/watch?v=Y8Ij9xboreA

1. End Ordovician (~445 Ma); ~12% of families, ~ 65%
species; large glaciation/sea level fall??

2. Late Devonian (~365 Ma); ~ 14% of families, ~ 72%
species; impact (Siljan Crater)?

3. End Permian (~250 Ma); ~ 52 % families, >90% species;
impact (Bedout Crater)?; flood basalts (Siberia); one
continent; global warming; low oxygen conditions

4. End Triassic (~210 Ma); ~ 12% families, ~ 65% species;
impact (Manicouagan Crater); flood basalts (Central
Atlantic)

5. End Cretaceous (65 Ma); ~11% families, ~ 62%
species; impact (Chixculub