Transcript Earth: An Ever changing planet

Overview of natural history
Breakdown of time
• Different periods of Earth’s
history are broken into sets of
time
– just like a year is broken into
months, weeks, days and hours
• Earth history is broken into eons,
eras, periods, epochs
Eons – Millions and Billions of years
• Haden: Earth before life evolved
3.5 to 3.9 Billion years ago (13% of Earth’s history)
• Archean: Earth with only bacteria like cells
3.9 to 2.5 Billion years ago (28% of Earth’s history)
• Proterozoic: Multicellular life forms
2.5 BYA to 540 MYA (48% of Earth’s history)
• Phanerozoic: Dinosaurs to now
• 540 MYA – present day
(11% of Earth’s history)
How time periods are distinguished
• Major geological events: The
movement of tectonic plates to
form continents & supercontinents
• Changes in climate: a change from
an ice ace to a warming period
• Mass extinctions or explosions:
Changes in the types of life forms
on earth
Haden Eon 4.6-3.9 BYA
• So hot that the rock was molten &
Water was vapor
• Lifeless, little O2 in the atmosphere
• Relative to a calendar year:
• Jan 1st – Feb. 25th
Archean Eon 3.9-2.5 BYA
• Earth cooled enough to have a
crust & ocean
• Life forms in the sea
• Bacteria & photosynthetic blue-green algae
Feb. 25th - April 17th
Proterozoic Eon: Precambrian Era
2.5 BYA – 540 MYA
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Super continent Rodinia
21% O2 in Atmosphere
First complex cell -July 13th
First multicellular organism (seaweed/algea)
– Aug 31st
Review of
Earth’s first
3.9 Billion
years
Haden
lifeless Earth
Proterozoic
Complex life,
multicellular,
First plants & soft
bodied animals all life
was in the oceans.
Archean
Prokaryotic life
Little O2
Paleozoic Era
From the Cambrian explosion to the
dawn of the dinosaurs
Cambrian - Permian period:540 MYA – 248 MYA
• Cambrian: Starts with a burst of new
life forms & all life in ocean
• Plants & animals evolved from simple
seaweed & sponges
• to fish in the oceans & insects,
amphibians, and early reptiles on land
• 1 Mass extinction in the ocean
• Nov. 17 – Dec 6
Triassic period to Holocene Epoch
248 MYA – present
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From the early dinosaurs to extinction 65 MYA
1st mammals, birds, and flowering plants
The ice age to modern civilization
Dec 7th - Midnight Dec 31st
First monkeyFirst human
Last Dinosaurs
First bird
Flowering Plants
First Mammals
First Dinosaurs
Review of last 248
Million years
White board Review
1.
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What was the surface of the earth like during the
Haden Era?
During which era did multicellular life evolve?
Which is a shorter period of time and eon or an
era?