Term
| Primary method of dating the earth |
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Definition
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Term
| Half-lifes of Radioactive-isotopes P, H, C, K |
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Definition
-32P = 14.3 days (31P)
-3H = 12.3 years
-14C = 5700 years (12C)
-40K = 1.3 billion years (40Ar) |
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Term
| Changes of the earth that have occurred over time |
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Definition
-oxygen concentration (rising)
-sea levels
-temp and humidity,
-meteor impacts
-continental drift |
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Term
| Laws of the Fossil Record |
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Definition
-Law 1: In sequence of sedimentary rocks, layers originally formed by lying horizontally
-Law 2: oldest are lowest, youngest are highest |
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Term
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Definition
| 4.5bya - 543mya -origin of earth to Cambrian Explosion |
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Term
| Evolutionary Milestones of the Precambrian Era |
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Definition
1.life arises
2.cells form (prokaryotic)
3. photosynthesis (cynobacteria- blue/green)
4. Sex happens (bacterial conjugation)
5. Eukaryotes form (protists: single celled eukaryote)
6. multicellularity (volvox: multicellular protist) |
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Term
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Definition
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Term
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Definition
-Buildup of many animal and plant forms (Cambrian Explosion: 540-510mya)
-ends with earth's greatest mass extinction (permian extinction) |
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Term
| Reasons for why we observe a Cambrian Explosion of diversity in the fossil record |
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Definition
1. Fossil record incomplete, diversification could have begun earlier.
2. Tens of millions of years still a very long time for evolution to take place.
3. Key innovations such as jointed appendages and jaws may have lead to escalation of biotic interactions and rapid co-evolution. Motile jawed predators select for defenses of prey (e.g. legs, shells, sensory capabilities).
-Colonization of terrestrial habitats. |
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Term
| Six Periods of the Paleozoic Era |
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Definition
• Cambrian(542-510mya):origin of animal phyla
• Ordovician(510-440mya):Colonization of land by plants and arthropods, diverse marine invertebrates
• Silurian(440-409mya):Diversification of early vascular plants
• Devonian(409-354mya):Diversification of bony fishes. First tetrapods and insects
• Carboniferous(354-290):Extensive forests, first seed plants, origin of reptiles
• Permian(290-245):Diversification of reptiles and insects. Largest mass extinction at end of period. 96% of marine animals went extinct. Many terrestrial extinctions as well |
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Term
| Earth's greatest mass extinction |
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Definition
| Permian Extinction: 251 mya |
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Term
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Definition
251-65mya
-age of dinosaurs |
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Term
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Definition
-age of dinosaurs
-evolution of flowering plants
-ends with sudden extinction of dinosaurs |
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Term
| 3 Periods of Mesozoic Era |
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Definition
-Triassic (245-206 mya)
-Jurassic (206-144 mya)
-Cretaceous (144-65mya) |
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Term
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Definition
-65mya aka cretaceous-tertiary boundary
-Worldwide iridium layer
-Dinosaurs did not go extinct (birds still exist)
-Mammals did not originate (small mammals co-existed with dino’s) |
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Term
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Definition
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Term
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Definition
-Quarternary Period: 1.8mya - present
-2 Epochs: 1.Pleistone and 2. Holocene(lasted 12,000 yrs) |
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Term
| Time when most large mammals in north/south america went extinct |
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Definition
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Term
| Possible causes of pleistocene extinctions of large mammals |
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Definition
-Climate change: Could be, but climate had fluctuated between glacial and interglacial periods many times without previous extinctions.
-Humans Hunters using 'clovis' points arrived in North America about 12-13 thousand years ago. As extinctions on other continents (e.g. Australia) also correlate with human arrival, THIS hypothesis seems likely |
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Term
| Alfred Wegener (1880-1930) |
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Definition
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Term
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Definition
1.Shapes match: Continents look like jigsaw puzzle
2.Plants and animals match:
similar fossils on different continents. Close matches between the coastlines of South America and Africa
3.Rocks match: Same types of rock at same age on different continents
4.Ice matches: Striations from glaciers on southern continents about 300mya. No glaciers of this age in what are now northern continents. Conclusion: Northern continents were equatorial at that time. |
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Term
| Mechanism of Continental Drift |
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Definition
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