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13 Cards in this Set
- Front
- Back
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Phylogeny
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a species family tree that is constructed in order to trace how it evolved through time
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Pleisomorphic vs. apomorphic traits
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Pleisomorphic = a trait that is ancestral; means that 2 species are directly related
Apomorphic = a trait that is derived; helps to pinpoint where a species split from its ancestors |
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Homologous vs. Analogous structures
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Homologous = characteristics (behavioral or morphological) that are the same due to common descent
Analogous = characteristics (behavioral or morphological) that are the same due to similar environmental pressures |
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7 levels of structural hierarchy
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Kingdom
Phylum Class Order Family Genus species |
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Relative vs. absolute dating
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Relative = places events and items into a sequence rather than giving real ages; based on stratigraphy and superposition
Absolute = AKA chronometric; techniques that provide a calendar age |
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Radiometric dating
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Absolute
• some action sets a "clock" to zero • some kind of radioactive decay records the passage of time |
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Biostratigraphic dating
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Relative
Compares fossils in order to place them into a time frame |
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Palemagnetism
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Relative
Comparison of polarities in the earth's layers in order to date something within them |
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Indirect vs. direct dating
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Indirect = dating objects or sediment around an object of interest in order to place it in a time frame
Direct = dating an THAT object of interest direct |
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Stratigraphy
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Sequence of layers in the ground
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Superposition
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Principle that governs the interpretation of stratigraphy
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Element
Isotope |
Element = pure chemical substance consisting of one type of atom distinguished by its atomic #
it's nuclei contain an equal # of protons and neutrons Isotope = atoms whose nuclei have the same number of protons but different number of neutrons, making it heavier |
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Stable vs. radioactive isotopes
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The number of stable isotopes remain in constant concentrations, while radioactive isotopes decay over time, according to the isotope's half life. These numbers can be compared to date objects
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