Paleontology, macroevolution and extinction-9 Flashcards Preview

evolutionary biology of animals > Paleontology, macroevolution and extinction-9 > Flashcards

Flashcards in Paleontology, macroevolution and extinction-9 Deck (10)
Loading flashcards...

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:
-cast formatio
-mold formation
-unaltered remains


how are fossils dated?

radioactive dating based on the ratios of decayed: non decayed nuclides


index fossil?

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


what factors could determine which fossils show up in the record for longer?

-broader ranges so greater persistence
-some organisms more likely to be fossilized