Earth's History Quiz #2

What is an index fossil?

• A fossil that helps scientists find other fossils.
• A fossil that scientists have not dated yet.
• A fossil that helps scientists date unknown fossils.
• A fossil that is from the earliest life forms on earth.

An index fossil is:

• found during a limited time period.
• widely distributed.
• Neither a or b.
• Both a and b.

An unknown fossil is found in the same layer or rock as two different index fossils. One of them existed 275 to 200 mya, and the other 250 to 150 mya. The unknown fossil must have existed:

• 275 to 150 mya.
• 250 to 200 mya.
• 200 to 150 mya.
• only around 250 mya.

What is a synonym for radioactive decay?

• Break down
• Build up
• Fall apart
• Destroy

What is radioactive dating?

• A way to find radioactive material.
• A method of determining the relative age of a rock or fossil.
• A method of determining the actual age of the earth.
• A method of determining the actual age of a rock or fossil.

What is a half life?

• The time it takes for half of a radioactive sample to decay to a stable form.
• The time it takes a sample to completely decay to a stable form.
• The age of a radioactive sample.
• Around 35 to 45 years.

What is relative dating?

• A method to determine the actual age of fossils.
• A method to determine the actual age of rock layers.
• A method to find fossils in a rock layer.
• A method to determine the relative age of fossils or rock layer.

Fossils in shallow layers of rock are ___________ than fossils in deeper layers of rock.

• older
• larger
• younger
• smaller

An intrusion of igneous rock is:

• younger than the rock layers it cuts through
• older than the rock layers it cuts through
• the same age as the rock layers it cuts through
• not found in sedimentary rock layers

A tree ring represents:

• the growth of a tree in the winter
• the growth of a tree in the summer
• the growth of a tree during the spring
• the growth of a tree in a single growing season