Lecture 4/5 Flashcards
88% of earths history happened in the _________
Precambrian Eon
42% Proterozoic
33% Archean
13% Hadean
The oldest evidence of life comes from the early part of the _____
Archean
The Mesozoic period ended _____ years ago
66 million
And that was when the Cenozoic Era began
The 4 Eons are
Hadean Archean Proterzoic and Phanerozoic
The Phanerozoic Eon is composed of what 3 era’s
Cenozoic (66Ma - Today)
Mesozoic (252 Ma - 66 Ma)
Paleozoic (539 MA- 252 MA) MA= Mega-annum (10^6 years)
How old is the earth?
4.567 GA (GA= 10^9 years) or 4.567 Billion years
What is the Giant impact Hypothesis
The Hadean earth was hit by a planet about the size of mars called Theia. This caused light material to eject into space and then unite to create the moon
Simple, single celled life evolved on earth during which period
Hadean
Likely as chemosynthetic bacteria feeding on chemicals brought to the surface at hydrothermal vents
The very oldest rocks are exactly _____ years old and come from the _____ period
4 Billion years old
From the Archean earth Period
Acasta Gneiss is a rock from this period located in the Canadian shield of the Northwest Territories
The oldest fossilized life on Earth are trace fossils called _________
Stromatolites
Earliest evidence of life comes from photosynthetic bacteria called_______
Cyanobacterial (or Blue-Green Algae)
These microscopic life forms live in colonies called “algal mat”
In the _______ time period, oxygen from cyanobacteria bonded with heaps of iron in the early oceans creating an ________
Proterozoic
Iron Sink - This is later depleted and around 1.9 Ga of oxygen builds up in the earth’s atmosphere
The first large Multicellular animal was the
Ediacaran Biota
From the end of the Proterozoic when enough oxygen was present in the atmosphoer for large life forms
In this Eon fossils became plentiful thanks to the development of animals and hard parts leading to the term ________
The Cambrian explosion which took place during the beginning of the Phanerozoic Eon
Camrian animals are much more complex as well, having advanced sensory organs such as eyes
In this era life begins to diversify, oceans are dominated by invertabrate animals but the first fish amphibians and reptiles are seen. On land plants and insects evolve
Paleozoic Era
The survivors of the Permian Mass extinction which ends the Paleozoic Era go on to diversify during the ___________ Era
Mesozoic
This becomes the age of the Reptiles as they dominate the skies, seas, and land.
After a large asteroid hits the Earth 66 MA Mammals and other survivors get to shine and diversify during the ______ Era
Cenozoic
“The Age of the Mammals”
The ______ epoch is often reffered to as the Ice Age
Pleistocene
The age of the earth is based on ___________
The age of meteorites- fragments of ancient planets/moons destroyed early in the formation of the solar system
