Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Geologic Time

No description
by

Trevor Heard

on 19 February 2014

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Geologic Time

Geologic Time
Development of Life and Major Events in Earth's History
Formation of Earth's Atmosphere
Evolution of Life
Outgassing
Oxygen in the Atmosphere
Earth's early atmosphere consisted of very different gases than today's:
hydrogen, methane, helium, ammonium, carbon dioxide, water vapor
Lighter
gases like H and He lost to outer space because Earth's
gravity
too weak to hold them
Earth's first
enduring
atmosphere was generated by
outgassing,
the release of gases from Earth's interior through volcanoes, a process which continues today through hundreds of active volcanoes
water vapor, carbon dioxide, sulfur dioxide
most abundant gases in this enduring atmosphere

As Earth cooled, water vapor
condensed
into clouds and torrential
rains
began to fill low-lying areas, which became the
oceans
Photosynthesizing
bacteria
in the oceans began to release oxygen into the water as a product of
photosynthesis
Oxygen bean to accumulate in the atmosphere as early as
2.2 bya
, and stabilized about
1.5 bya
Atmospheric oxygen allowed for
life
on earth, and provided protection from
UV radiation
in the form of
ozone (O3)

First significant atmospheric oxygen - 2.2 bya
First stable atmospheric oxygen - 1.5 bya
Great Permian Extinction - 250 mya
Pangaea reaches it's maximum size - 250 mya
Great Mesozoic Extinction - 65 mya
Defines boundary between
Paleozoic
and
Mesozoic
eras
Resulted in extinction of
70%
of land dwelling vertebrates and up to
90%
of all marine organisms
The most widely accepted hypothesis involves a combination of the following:
massive
eruptions
of lava and
carbon dioxide
and
sulfur dioxide
the release of carbon dioxide would enhance the
greenhouse effect
and sulfur dioxide would result in huge amounts of
acid rain
increasing
temperature
would decrease oxygen in
sea water
, and increase amount of
anaerobic bacteria
, which release
hydrogen sulfide gas
into the atmosphere
hydrogen sulfide is
toxic
to both
plants
and
animals
on land
Defines the boundary between
Mesozoic
era (middle life) and
Cenozoic
era (recent life)
Approximately
75%
of all plant and animal species died out
Most strongly supported hypothesis is as follows:
Earth was struck by a
meteorite
approx. 10 km in diameter, and traveling 90,000 km/h
suspended
dust
from impact greatly reduced amount of
sunlight
reaching Earth's surface, resulting in
global cooling
inhibited
photosynthesis
, and therefor,
food
production
reduced photosynthesis resulted in high levels of
carbon dioxide
, followed by period of
global warming
Extinction of
dinosaurs
opened up habitat for surviving
mammals
, thus beginning the age of mammals
Full transcript