GenBio2 Reviewer Lesson 1

A remnant, impression, or trace of an animal or plant of a past geologic age that has been preserved in Earth's crust.

It is the primary source of information about the history of life on Earth

How old is the Earth?

• 4.3 Billion Years Old

• 4.4 Billion Years Old

• 4.5 Billion Years Old

• 4.6 Billion Years Old

A record of life forms and geological events in Earth's history

The largest division of geologic time scale

• Epoch

• Eon

• Era

• Period

Proterozoic, Archean and Hadean Eon combined. Clustered as a Supereon

It is the "Age of Early Life".

• Precambrian

• Phanerozoic

• Mesozoic

• Paleozoic

Planet was characterized by a partially molten surface, volcanism, and asteroid impacts.

• Hadean

• Archean

• Proterozoic

• Mesozoic

Earth's crust cooled down enough forming continental plates and the first signs of life appeared

• Hadean

• Archean

• Proterozoic

• Mesozoic

First organism on Earth