PCB 4674 Lecture Notes - Lecture 47: Hadrosaurid, Trilobite, Ct Scan
14 Apr 2018
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Because: no hard parts (annelids/flatworms) (fossilize in special conditions, organisms live in area that wasn"t forming sedimentary rock (desert doesn"t, marine organisms fossilize) It happens frequently because sediments are accumulating quickly in the bottom of lakes/ocean. Other traits can be known, like footprints and bones. What does the fossil record help us learn about extinct species: morphology, behavior (trackways, nests, stomach content, development (trilobite lifecycle, cellular structure (sem, shows plumage, function of parts (cat scan for hadrosaur crest) When put onto a plot, there is a clear trend but there are gaps. This is consistent with molts, therefore we know how they developed. It helped create very accurate models of shape/interior. We found that it was connected to the nasal cavity. There is sound generated by blowing air/used as trumpet. Confirmed since ears are tuned to this frequency -- optimal pitch of crest was optimal pitch for hearing. If it happened before it had a chance to decay.
