Download 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
•
•
•
•
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
•
•
•
•
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.
2.
3.
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?