The Precambrian Time
Felipe González.
Daniela Ramos.
María Alejandra Vargas.
Daniel Pérez.
Valentina Stozitzky.
10B
4.5 billon years ago
The earth was born!!!
4
Geologists and paleontologists
• Geologic time scale
-relative, absolute dating.
-major divitions of the geologic time scale.
Eons
Stop! Notice fabulous table on your book
Era
Periods
PRECAMBRIAN• It means before the
“cambrian period”.
• Before the formation of rocks with recognizable
fossils.
• Cryptozoic or "obscure life“.
90%
Divided into three Eons
HadeanArchean
Proterozoic
Precambrian Environment The atmosphere was
reduced into gases and oxygen.
The planet had a redish tint.
The seas had a green bright tone.
Oxygen began to be produced in large quantities.
Oxygen had chimical reactions: Iron and oxidable surfaces.
The planet developed a solid crust that created water vapor.
Scientist think that seas were created by a volcanic catalist.
Important info…Scientists think the first
seas gave rise to life.
hot, mineral-rich volcanic vents actied as catalysts for chemical reactions .
Other bubbles contained self-replicating substances.
The water bubbles that formed-1st cell membranes.
chemicals around them combined to produce energy-using, living cells.
The first living organism were microscopic bacteria founded in fossils.
Fossilized bacteria and blue-green algae 3,500 million years ago.
Eukaryotic cells2,100 million years after.
Protozoa.
Found mainly in the oceans.
Forms of life
Invertebrates.
Evolved later on (700 million years ago)
Sponges, corals, jelly fish
HADEAN EON
From 4567 to 3800 mya.
• Formation of the Solar System
• Formation of the Earth.
• Moon is created.• Oceans of liquid rock,
boiling sulfur, and impact craters everywhere.
• The air is hot, thick, steamy.
• No oxygen -water vapor.
-carbon dioxide.
The big bang Splashh!
• No rocks of this time have been found.
ARCHAEAN EON
From 3800 to 2500
• Surface of the Earth molten solid rock.• Water
condensed in liquid form.
• 15 hours long.
• 1st Prokaryotes appeared.
-oxygen producing bacteria.- cyanobacteria (blue-
green algae).
• Atmosphere (75% nitogen,15% carbondioxide.)
• The continents have not formed yet. (global ocean)
PROTEROZOIC EON
From 3800 to 2500
Divided in Era and Periods• Paleoproterozoic Era
Siderian Period - Stable continents first appeared.
• free oxygen is found -oceans and atmosphere.
• Oxygen catastrophekilled many organisms.
• Start of Huronian ice
age.
PROTEROZOIC EONFrom 3800 to 2500
• Rhyacian Period - Organisms with mitochondria capable of aerobic respiration appear.
• Orosirian Period - Mountain development - Oxygen starts accumulating in the atmosphere
• Statherian Period -single-celled life appeared. - lots of bacteria and archaeans.
PROTEROZOIC EON
From 3800 to 2500
• Mesoproterozoic Era Calymmian Period ) - Oxygen builds up in the atmosphere. - Formation of ozone layer. - Eukaryotic (nucleated) cells appear.
• Ectasian Period - lots of green (Chlorobionta) and red (Rhodophyta) algae.
• Stenian Period - Spore-gamete formation sexual reproduction. - Formation of the supercontinent.
16
• http://www.prehistory.com/precambrian.htm
• http://fossils.valdosta.edu/era_precambrian.html
• http://www.scientificpsychic.com/etc/timeline/timeline.html
• http://www.geo.msu.edu/geogmich/Precambrian.html
Recommended
