Vocabulary
Superposition
Index Fossils
Absolute Dating
Earth's Changes
100
The preserved remains or traces of an organism that lived in the past
fossil
100
What is the oldest layer in this image?
Layer Q
100
Do index fossils help determine relative age or absolute age through correlating rock layers in different locations?
Relative Age: Index fossils are found in many places and lived during a short time period, so they help scientists match rock layers across different locations to determine relative age.
Do not get an exact number from fossil comparison
100
The time it takes for half of a radioactive element to decay into stable element is called the_______.
half-life
100
Scientists found that the desert of Peru used to be underwater. What fossils would they be least likely to find?
Dinosaur fossils, insect fossils, non-marine fossils
200
The age of a rock compared to the age of other rocks based on their organization.
Relative Dating
200
Is the age of the rock layers described using relative or absolute dating? Why?
At Grand Canyon Park, the Kaibab rock layer is found on top of the Toroweap rock layer. This means the Kaibab layer is younger than the Toroweap layer.
relative dating because we are comparing layers and not getting the exact age.
200
Which two traits make a fossil a good index fossil?
widespread geographically, short lifespan
200
Why are radioactive substances useful for determining the absolute age of rocks?
Because they decay at a constant, predictable rate, which allows scientists to calculate the exact age of the materials.
200
What do fossils show about how life today compares to life from the past?
Fossils show that life has changed from simple to more complex over time.
300
Measuring the decay of radioactive material in rocks to determine the exact age.
Absolute Dating or Radioactive Dating
300
Which rock layer in the diagram seems to be the oldest?
Layer A
300
In rock layers, trilobite fossils are found lower than coral fossils, and coral fossils are found lower than ammonite fossils. Order these 3 fossils from the youngest to the oldest.
-ammonites (youngest)
-corals
-trilobites (oldest)
300
Why can't we use radiocarbon dating for remains like dinosaur bones and ammonite shells?
Too much time has passed since the organism died- only useful for organisms that recently died! up to 60,000 years
300
Scientists have found the same types of plants and fossils on different continents suggesting that they were all once joined in a single landmass called Pangea. What scientific theory was supported by this evidence?
Theory of Plate Tectonics, a revision of the hypothesis of Continental Drift
400
The same fossil found in two different places, telling us that the rock layers are a similar age. Used to match/correlate rock layers.
Index Fossils
400
What is the youngest feature in this image?
Igneous Intrusion B
400
How could I use fossil remains as a geologist?
To determine the age of rocks in the surrounding area.
OR
Determine what the past environment/climate was like.
400
Select the correct term to complete the sentence:
During ________, atoms of the radioactive element break down into another, more stable element.
A. Half-life
B. Radiation
C. Energy and particles
D. Radioactive decay
D. Radioactive decay.
400
When scientist find buried marine fossils at the top of a mountain, what does it suggest?
The rock layer was once submerged underwater.
500
The geologic principle/law that states that the youngest rocks are at the top and oldest rocks are at the bottom.
law of superposition
500
List the layers of rock from oldest to youngest.
E, B, C, D, A
500
If scientists find the same fossil in multiple places around the world, what can they conclude?
The rock layers are the same age
500
Why is measuring the decay of radioactive elements the most accurate way to measure a rock's age?
It gives us an exact number of years for the age.
500
Scientists were exploring a place in the Arctic where it is very cold called the Dry Valleys and found fossils of moss, small shrubs, and insects. What can be inferred about the environment in the past?
For insects and plants to survive in this area, it had to be warmer and more welcoming to life than it is today.