Fossil Record and Organic Molecules

Paleontologists provide evidence for all of the following EXECPT...

• how organisms changed overtime

• where organisms first appeared

• when organisms went extinct

• the size of the earth

fossils in lower layers are older then the fossils in the higher layers

• carbon dating

• radioactive dating

• relative dating

• sedimentry rock

half life

• amount of time for 1/2 of radioactive atoms to decay

• determines the age of the fossil and based on amount of remaining isotpes it contains

• sediment, sand silt and clay

An isotope of caesium (Cs-137) has a half-life of 30 years. If 1.0g of Cs-137 disintegrates over a period of 90 years, how many grams of Cs-137 would remain?

• 1.25g

• 0.125g

• 0.000125g

• 12.5g

Selenium-83 has a half-life of 25.0 minutes. How many minutes would it take for a 10.0 mg sample to decay and only have 1.25 mg of it remain?

• 75 minutes

• 75 seconds

• 75 hours

• 75 days

Q4. What is the half-life of a radioactive isotope if a 500.0g sample decays to 62.5g in 24.3 hours?

• 8.1 hours

• 6.1 hours

• 5 hours

• 24 hours

determines the age of the fossil and based on the amount of remaining isotope it contains

• relative frequency

• carbon dating

• half life

• relative dating

Early Earth history when atmosphere was toxic

• 3.5 billion years ago

• 4.6 billion years ago

• 4 billion years ago

• 2.2 billion years ago

earth cooled and oceans formed and where brown due to iron. skies were pink and orange .... years ago

• 2.2 billion

• 3.5 billion

• 4.6 billion

• 4 billion

Miller Urey experiment - said that condition of early earth could form organic molecules

• results where that meteors could carry organic molecules and possible microbes to earth

• results where amino acids and concluded organic molecules could form spontaneously

• results where nucleic acids and concluded that meteors brought DNA to earth