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Bio 181 History of the Earth

Terms in this set (24)

where are fossils found?
sedimentary rock
relative dating
working off of the geological laws of superposition, layers on top of other layers are going to be different.
Radioactive material
One thing they noticed is different materials emitted energy and the amount varied. These elements decayed at different rates. When a radioactive element decays it converts to a different type of element.
Half life
length of time required for half of the radioactive atoms in a sample to decay
geological record
a standard time scale that divides Earth's history into 3 eons and further subdivisions
Precambrian
first 2 eons lasting around 4 billion years
Phanerozole
3 eras that represent the majority of multicellular life:
1. Paleozonic
2. Mesozoic
3. Cenozoic
Paleozonic
542 mya
Mesozoic
251 mya
Cenozoic
65.5 mya
Mass extinctions
1. Permian
2. cretaceous
Permian (250 mya)
96% of all life wiped out (biggest mass extinction event that we know about) This is associated with Pangea broke apart.
Cretaceous (65 mya)
asteroid
Plate tectonics
® the study of the movement of the major crustic plates of the lithosphere float on top of the magma found in the mantle
2 types of tectonic plates
1. continental
2. oceanic
Chemical evolution
→ life developing from nonliving matter. At some point the first cell had to emerge.
Steps of chemical evolution
1. abiotic synthesis of small organic molecules
2. joining of the molecules into polymers
3. Packaging of these molecules into "protobionts"
4. Origin of self-replicating molecules ("RNA world")→ inheritance possible
prokaryotes
1. Bacteria
2. Archae
Cambrian explosion
Animal diversity exploded around 543 mya
Colonization of land about 500 mya
beginning of Ordovician period
Devonian Period
Age of fishes
Permian Period
"Age of Amphibians"
Mesozonic Life
"age of reptiles"
Cenozoic Era
"age of mammals"
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