Ch 4-1
Ch 4-2
Ch 4-3
Ch 4-4
Misc.
100
What is the definition of a fossil?
preserved remains or traces of living things
100
How do geologists understand the relative ages of igneous rocks?
The age of the rock compared to other rocks
100
What happens during radioactive decay?
atoms of one element breaks down to form atoms of another element
100
During which geologic Period were earliest grasses deposited?
Paleogene
100
In what type of rock are fossils usually found?
Sedimentary rock
200
How do fossils form?
When living things die and are buried by sediment. The sediments slowly harden into rock and preserve the shapes of the organisms
200
What’s the difference between an intrusion and an extrusion?
Intrusion- magma that cools and hardens beneath the surface
Extrusion- lava that hardens on the surface
200
When a radioactive element decays, what does it release?
particles of energy
200
What are Eras of geological time subdivided into?
periods
200
What parts of an organism are most likely to become a fossil?
Hard parts, bones
300
A type of organism that no longer exists on Earth is said to be what?
Extinct
300
A student found this index fossil of Cryptolithus in the bedrock near his home. What was the approximate age of the bedrock?
Approximately 466 million years old
300
Scientists use radioactive dating to do what?
scientists use the rate at which elements decay to determine the absolute age of rocks
300
In which segment of the Earth's geologic history are very few fossils found?
precambrian
300
What does a paleontologist do?
use fossils to build up a picture of Earth's environments in the past
400
The fossil record provides evidence to support the theory of what? Explain this theory. (2 part answer)
*Theory of Evolution
*the gradual change in living things over a long period of time
400
For which time frame of the Earth's geologic history are fossils rarely found?
Precambrian
400
how much of the radioactive element remains after three half-lives?
12.5%
400
In which segment of the Earth's geologic history are the most fossils found?
Paleozoic
400
Which event is generally accepted as the cause of the mass extinction that occured 65.5 million years ago?
asteroid impact
500
What is the fossil record and what does this show? (2 part answer)
*provides evidence about history of life on Earth
*how species have evolved over time
500
To be useful as an index fossil, a fossil must have what two characteristics?
*widely distributed
*represent a type of organism that existed only briefly
500
Explain what half-life is.
time it takes for half of the radioactive atoms to decay
500
Name two other organisms from your ESRT that existed when the nautiloid and ammonoid fossils found in layer F were deposited.
ANY TWO-Phacops, ctenocrinus, stylonurus, aneurophyton, naples tree, bothriolepis, pleurodictyum, platyceras, mucrospirifer
500
During which Epoch and Period are most Index Fossils found?
Middle Devonian, 6: C, F, G, N, X, and Z