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)
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1

what is macroevolution?

evolution over long periods
large evolutionary changes e.g. new organs and body plans

2

how are fossils formed?

any of the following:
-compression
-mineralisation
-cast formatio
-mold formation
-unaltered remains

3

how are fossils dated?

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

4

index fossil?

a fossil used to date

5

cambrian explosion (565-525 mya) first time we see life with?

segmented body plans and notochords which are primitive nervous systems e.g. pikaia

6

how is it known that fossils marks were above water?

because there were ripples in sandstone caused by wind

7

what is a micro CT scan?

non invasive imaging (used for amber samples and to look at inner ear of fossil)

8

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

9

how do we know there was a mass extinction event at the end of the cretaceous?

presence of certain chemicals like iridium

10

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