Chapter 7 Trip Through Geologic Time

An _____ is a gap in the geologic record where some rock layers are lost because of erosion

The extinction of the dinosaurs gave warm-blooded vertebrates called ____ to live

Earth's earliest atmosphere lacked gas which was necessary for life as we know it to exist 

What is L called

What era would have found the dinosaurs

What is H called

During the Cambrian Explosion that began the Paleozoic Era, many new forms of life that evolved

Fossil formed when minerals replace all or part of an organism

Which layer is the youngest

Which layer is the youngest?

The time it takes for half the radioactive atoms to decay

Scientist who studies fossils

What do scientist use to find the age of bones

Which layer is the oldest

Which layer is the older H or C

Geologists use radioactive dating to

The climate in the center of Pangaea at the end of the Paleozoic Era was probably....

During the Quaternary Period a series of ______ that cooled and warmed the climate

Relative age of rocks

Jawless fish were the first _______ or animals with backbones

What What type of rock would H be made of?

What is the age of an intrusion of igneous rock in relation to the sedimentary rock it passes

What do scientist study to see how organisms change over time

radioactive dating works best on what type of rock?

Radioactive decay occurs when atoms of some elements

Earth's atmosphere, oceans, and continents began to for in what Era

What are fossils?

Potassium-40 is useful for dating very old rocks because its ______ is 1.3 billion years.

Which layer is the younger L or C