Flashcards in Paleontology, macroevolution and extinction-9 Deck (10)
what is macroevolution?
evolution over long periods
large evolutionary changes e.g. new organs and body plans
how are fossils formed?
any of the following:
how are fossils dated?
radioactive dating based on the ratios of decayed: non decayed nuclides
a fossil used to date
cambrian explosion (565-525 mya) first time we see life with?
segmented body plans and notochords which are primitive nervous systems e.g. pikaia
how is it known that fossils marks were above water?
because there were ripples in sandstone caused by wind
what is a micro CT scan?
non invasive imaging (used for amber samples and to look at inner ear of fossil)
what are the theories that explain the appearance of complete forms in the record and no precursors?
-rapid diversification punctuated equilibria (speciation sometimes faster)
-incomplete fossil record
-more ecological niche- NS
how do we know there was a mass extinction event at the end of the cretaceous?
presence of certain chemicals like iridium