Other important points in interpreting the fossil record

Other important points in interpreting the fossil record -...

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Other important points in interpreting the fossil record: Dating fossils requires radiometric dating of associated igneous rock . (sedimentary rock is of highly mixed origin). Moreover, fossils and the bed in which they lay have been reworked and redeposited. Careful stratigraphy and analyses of surrounding strata must be done to provide meaningful data about the relative and absolute ages of fossils. Gaps in the record . The nature of the fossilization process almost assures that there will be gaps in the fossil record. We have to live with it. What do we know about fossil organisms? Certain associated information allows informed speculation about the biology of fossil organisms. Large dinosaurs that left tracks without tail dragging marks suggest an active lifestyle ? (other fossil remains do show clear evidence of tail dragging and footprints). Other assemblages show fossil bones of adults associated with nest sites and eggs: suggests parental care
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Unformatted text preview: ? Simple footprints may seem like a cute form of fossil evidence. Actually a lot can be learned about the organisms: one can corroborate estimates of the animal's size; one can measure distance between prints and obtain information about gait, travel speeds, etc.; these interpretations further dictate a host of different physiological processes that might be able to sustain such a manner of locomotion. These types of issues are the main point of this lecture: from a small amount of fossil information, certain biological interpretations are implied simply by the necessary biological attributes that go along with a given footprint size, shape, etc. Fossils can help define ancestral character states and thus help clarify relationships of extant organisms. However, this cannot be done without the extant organism's character states (i.e. fossils alone aren't much help. Is Archaeopteryx birdlike enough to be considered a bird ancestor?...
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