Geologic Time and Fossil Concepts

5.3.a Geologic Time

I can describe how fossils are used to understand that life has become more complex over geologic time.

Geologic Time Scale

• Earth's 4.6 billion-year history can be investigated and understood by studying the rock record and fossils found in sedimentary rocks.

• Time is divided based on major or catastrophic events.

• The divisions of time from largest to smallest are: eon, era, period, epoch, and age.

Multiple Choice

The geologic time scale is divided into units of time based on what?

• a specific amount of time

• the evolution of humans

• major or catastrophic events

• no one knows

Multiple Select

Scientists can investigate and understand Earth's 4.6 billion year long history by studying all of the following. (Select all that apply)

• Fossils found in igneous rocks

• Fossils found in sedimentary rocks

• Fossils found in metamorphic rocks

• Rocks

Multiple Choice

Which of the following choices puts the divisions of time in order from the largest amount of time to the smallest amount of time?

• age, epoch, period, era, eon

• eon, era, period, epoch, age

• period, eon, era, epoch, age

• age, eon, epoch, era, period

Multiple Choice

When looking at layers of rock, where would the OLDEST rocks and fossils be found?

• on the top

• on the bottom

Precambrian Eon

• 90% of all time on Earth

• 4.6 billion years ago until 542 million years ago

• 3 eras, in order from first to last: Hadean, Archean, Proterozoic

• The Earth forms, oceans form, and there is NO life except VERY simple, single-celled organisms in the oceans.

Phanerozoic Eon

• Time of "visible life" from 542 million years ago until the present

• 3 eras, in order from first to last: Paleozoic, Mesozoic, Cenozoic

• The Paleozoic Era is known as the Age of Fish

• The Mesozoic Era is known as the Age of Reptiles when dinosaurs ruled the land

• The Cenozoic Era is known as the Age of Mammals

Multiple Choice

In which EON do the Hadean, Archaean, and Proterozoic Eras belong?

• Cenozoic

• Paleozoic

• Precambrian

• Mesozoic

Multiple Choice

In which EON do the Paleozoic, Mesozoic, and Cenozoic Eras belong?

• Archaean

• Phanerozoic

• Precambrian

• Hadean

Multiple Choice

Which of the following lists the evolutionary events in order from first to last?

• age of fish, simplest life, age of mammals, age of reptiles

• simplest life, age of fish, age of reptiles, age of mammals

• age of reptiles, age of mammals, simplest life, age of fish

• age of mammals, age of reptiles, age of fish, simplest life

Multiple Choice

In which EON did the Earth and oceans form, and the first simple cells appear?

• Paleozoic

• Precambrian

• Phanerozoic

• Cenozoic

Multiple Choice

In which EON did the ages of fish, reptiles, and mammals happen?

• Proterozoic

• Precambrian

• Hadean

• Phanerozoic

Multiple Choice

True or False: Dinosaurs did NOT exist on Earth at the same time as humans.

• True

• False

Multiple Choice

True or False: Life on land evolved long before life in the oceans.

• True

• False

Multiple Choice

True or False: As life evolved on the Earth, it became more complex and more diverse (meaning that there are more species).

• True

• False