Geologic Time Scale Flashcard

Front

What is the timeline created by geologists called?

Back

Geologic timescale

Front

What do geologists look for in sedimentary rock layers to map out Earth's history?

Back

Fossil record and mineral composition

Front

What rule helps geologists determine the relative ages of rock layers and fossils? Options: Law of Original Horizontality, Law of Lateral Continuity, Law of Crosscutting Relationships, Law of Superposition

Back

Law of Superposition

Front

What is the name of the rule that states the feature that cuts through the other is younger?

Back

Law of Crosscutting Relationships

Front

What are fossils that are only found on a specific section of the geologic timescale called?

Back

Index fossils

Front

What evidence can help geologists figure out a rock's relative age? Mineral composition, Fossils, Geologic events

Back

All of the above

Front

When did the first multicellular life form according to the geologic timescale?

Back

600 million years ago

Front

What did relative dating help geologists figure out about the evolution of life?

Back

First single cellular life formed 3.8 billion years ago; Stegosauruses were extinct before T-Rex's existed; Modern humans didn't exist until about 200,000 years ago.