Term
| Metozoans, ___ animals, exist in 35 phyla today. Fossil record has helped preserve those with hard shells, not with soft. These animals share the following synapomorphies: ___ (three things). |
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Definition
multicellular
multicellular, mobility and heterotrophy (getting energy from complex organic molecules) |
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Term
| The "Cambrian Explosion," where a vast diversity of animals appeared in fossil records occured about ___mya. A famous area for finding fossils is the ___ in Canada. |
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Definition
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Term
| The half-life of carbon is about 5,700 years. Overtime the ratio of ___ decreases, which is how scientists can determine the age of a fossil up until about 50,000 years ago. |
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Definition
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Term
| For fossils older than 50,000 years, if there is neighboring igneous (volcanic) rock present, ___ or ___ can be used to date it; their half-lives are about 1.25 billion years. |
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Definition
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Term
| For fossils that are older than 50,000 years, if there is no igneous rock present, scientists can use ___, using records of Earth's known magnetic field. |
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Definition
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Term
| Dinosaurs are thought to have gone extinct because of a meteor and volcanic activity in the Cretaceous-Tertiary period (~65mya). Earlier than that, there was a mass extinction in in the Permian-Triassic period, where apprxoimately ___% of all marine species and ___% of all land species went extinct. |
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Definition
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Term
| There are many possible reasons for mass extinction. Besides meteors, there are also ___ (two things). |
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Definition
varyation of sea levels
major volcanic activity, sending basalt into the atmosphere |
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Term
| Alfred ___ proposed the idea of ___, he published his findings in his book, The Origin of Continents and Oceans, in 1912. |
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Definition
Wegener
continental drift |
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Term
| In terms of supercontinents, Rodinia (___bya) preceeded ___, which split into Laurania and ___. |
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Definition
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Term
| Snowball Earth was believed to occur in time between the supercontinents ___ and ___, during the ___ period. It was thought to occur, because most of the land was near the equator, causing a large uptake of ___ from erosion. |
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Definition
Rodinia
Pangaea
Cryogenian
CO2
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Term
| The Cambrian Explosion took place ___ Snowball Earth. |
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Definition
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Term
| Snowball Earth most likely ended because of ___. |
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Definition
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Term
| The Cambrian period shows the first evidence of animals with ___ skeletons. |
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Definition
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Term
| There are many theories as to why the Cambrian Explosion occured. ___ may have been able to change easier, or the environment may have been full of ___. It is also possible that there wasn't an explosion, there just aren't a good amount of fossils prior. |
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Definition
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Term
| Bilaterians are ___; they all have three germ layers. |
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Definition
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Term
| "Eumetazoans" encompass ___ and ___, but do not include ___ and ___. This is because ___ and ___ are not organized in germ layers. |
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Definition
diploblasts
tripoblasts
sponges
placazoa
sponges
placazoa |
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Term
| Bilaterians, AKA ___, have two subclasses: protostomes and deuterostomes. In protostomes, the ___ forms first from the blastopore during gastrulation, in deuterostomes the ___ forms second. |
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Definition
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