Paleontology, macroevolution and extinction-9

Question 1

what is macroevolution?

Answer 1

evolution over long periods

large evolutionary changes e.g. new organs and body plans

Question 2

how are fossils formed?

Answer 2

any of the following:

• compression
• mineralisation
• cast formatio
• mold formation
• unaltered remains

Question 3

how are fossils dated?

Answer 3

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

Question 4

index fossil?

Answer 4

a fossil used to date

Question 5

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

Answer 5

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

Question 6

how is it known that fossils marks were above water?

Answer 6

because there were ripples in sandstone caused by wind

Question 7

what is a micro CT scan?

Answer 7

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

Question 8

what are the theories that explain the appearance of complete forms in the record and no precursors?

Answer 8

• rapid diversification punctuated equilibria (speciation sometimes faster)
• incomplete fossil record
• more ecological niche- NS

Question 9

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

Answer 9

presence of certain chemicals like iridium

Question 10

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

Answer 10

• broader ranges so greater persistence

- some organisms more likely to be fossilized