Lecture 1

Question 1

Lead 204 is not produced by radioactive decay and is –

Answer 1

constant throughout geologic time

Question 2

lead – comes from the radioactive decay of uranium 238 the half life is about 4.7 Ga(age of the Earth)

Answer 2

206

Question 3

lead 207 comes from the radioactive decay of uranium 235 the half life is about –

Answer 3

0.7 Ga

Question 4

no rocks only a few tiny materials

Answer 4

Hadean

Question 5

5 mass extinctions based on the number of families of easily –

Answer 5

skeletonized marine invertebrates

Question 6

characters are properties of organisms (either anatomical or molecular) that can be used to reveal –

Answer 6

relationships

Question 7

crocs are – of birds

Answer 7

sister groups

Question 8

dinosaurs are – of birds

Answer 8

plesion