Fossil Record

How do fossils end up at the bottom of bodies of water?

Small particles are carried by streams and rivers into lakes or seas eventually settling to the bottom.

What is radioactive dating?

carbon 14 dating; assign an absolute age (very precise) to fossils based on the amount of remaining radioactive sample it contains.

What does a fossil record provide?

evidence about the history of life on Earth

What is fossil formation?

the preserved remains or traces of animals and plants

What happens after small particles settle to the bottom of a body of water?

As layers of sediment build up over time, dead organisms sink to the bottom and become buried (remains must be kept free from decay)

What information do fossil record show?

Fossils occur in a particular order; shows that life on Earth has changed over time. NOTE: 99% of all species that have ever lived on planet Earth are now EXTINCT (species has died out)

What happens after fossil sediments build up over time?

Weight of layers of sediment compress remains where they are turned into rock.

What is relative dating?

age of fossil determined by comparing its location to other fossils with sediment.

What lies at the bottom of the rock?

at the bottom are the oldest remains with the "youngest"/most recent fossilized remains near top

What is Carbon 14?

has a standard decay rate(1/2 life of 5730 years) it is taken up by organisms while they are alive yet begins to decay upon death. Compare this to the normal isotope.(Carbon 12) which is not radioactive and does not decay upon death. Therefore, by comparing the amounts of 14C/12C one can precisely determine the age of the fossil.

What does a fossil record demonstrate?

how different groups of organisms have changed over time; a way to infer what past life forms were like. 1. structure of the organism 3. What organisms ate them 2.What organism ate 4. Environment lived in.

What is a fossil record?

it provides information about how life changes over time

What is half life?

length of time required for half of radioactive atoms in sample to decay.

How do fossils form in rocks?

within sedimentary rock(expose existing rock to rain, wind and cold break rock down to small particles of sand and clay)