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Macroevolution
-major change over long periods of time
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Sedimentary rocks
- Older strata at bottom, higher strata younger
- Fossils of similar are distributed on earth
- Certain fossils are found in younger rocks….older rocks Higher strata fossils closely related to modern organisms
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Radioactive isotopes
- Half the remaining radioactive material decays to become
- stable isotope
- Ratio of C14:C12, when it decrease age is dated
- Halflife of 157 years
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Precambrian 3bya
- -least evidence and knowledge of
- small and aquatic
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Continental drift
- movement of lithospheric plates and continents they contain
- 25 miles thick
- Affects:climate, distribution of organisms, sea level
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Pangea
- -magma activity
- Volcanic ash effected sun rays hitting earth---cold
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Meteorites
- -Iridium originated from them
- Hit earth and circulated in atmosphere and settled on ground Extinction of dinosaurs
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Earliest life form
- Anaerobic bacteria
- 3.8 billion years old
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Major patterns
- Precambrian
- Paleozoic
- --Cambrian
- --Ordovician
- --Silurian
- --Devonian
- --Carboniferous
- --Permian
- Mesozoic
- --Triassic
- --Jurassic
- --Cretaceous
- Cenozoic
- --Tertiary
- --Quartenary
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Cambrian 542-488 mya
- Continental drift cause the plates come together (GONDWANA LAND) near southern pole
- Life was blossoming-most phyla came into existence-marine species
- “Cambrian Explosion”
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Ordovician 488-444mya
- Marine-brachipods, mollusks
- Glaciersover S continents
- Sealevels down 50 meter- Temp down
- 75% species extinct
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Silurian 444-416 mya
- Continents merge
- Marinelife rebound-open water swimmers First vascular plants
- First arthropods-scorpions millipedes
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Devonian 416-359 mya
- Plates continue to come together
- Great diversification of coral animals
- Great-shelled cephalapod mollusks were prevalent
- 75% extinction 2 meteorites
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Carboniferous 359-297 mya
- Crinoid gardens-echinoderms
- Tree-sized
- Glaciers in high latitudes of S continents
- Swamp forests--todays coal
- Amniotes-eggs in dry places
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Permian 290 mya
- Continents come to form Pangea
- Volcanic events
- Glaciation-due to ash
- Massive climate change
- Massive extinction 96%
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Mesozoic 251 mya
- Age of dinosaurs
- Jurassic-dinosaurs thrive
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End of Crustaceous period
- —meteor eliminated dinosaurs and end of Mesozoic Cretaceous-continents move apart
- Pangea euroasia+gondwana
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Oxygen levels
- 1.Increase in O2- 2.4 bya bacteria used water’s H for photosynthesis
- Cyanobacteria
- Aerobesreplaced anaerobes
- 2.Evolutionof large vascular plants in expansive lowland swamps
- 359-297mya
- Oconcentrations were all time high
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Biota
Flora
Fauna
- Biota-all organisms living in a particular time
- Flora-plants
- Fauna-animals
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Rates of evolutionary change
- Little change--IE Ginko plants, horseshoe crabs, sea urchin Gradual change-gradualism
- Rapid change-Punctuated equilibrium
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Scarcity of fossils
- Decomposition
- Rocks are transformed
- Inaccessible
- Hard-skeletonswithstand
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Living fossils
-much alike organisms from along time ago still alive
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Extinction
- 99% of all species that have ever lived on earth are extinct
- Environment is key factor
- Land/marine rates are different
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Future of Evolution
- Artificial selection
- Genetic engineering
- Indirect means
- --Pollution
- --Movement of exotics
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