(8) Geologic Time Scale

Fossils are

• molds and casts of organisms that live today

• preserved remains or traces of organisms that lived in the past

• drawings of ancient animals and other organisms

• footprints or burrows of small animals that live today

Tags

NGSS.MS-LS4-1

What is the principle of Uniformitarianism?

• Earth's eras occurred during uniform time spans

• organisms that lived in the past can be preserved

• there are no gaps in the geologic record

• processes that operate today also operated in the past

Tags

NGSS.MS-ESS2-1

What has studying fossils allowed scientists to do?

• predict which organisms will become extinct

• describe past environments and the history of life

• analyze the chemical composition of sedimentary rocks

• study ocean temperatures at different depths

Tags

NGSS.MS-LS4-1

Geologists use radioactive dating to

• determine the relative ages of rock layers

• tell the difference between molds and casts

• determine the absolute ages of rocks

• tell where one soil horizon ends and the next one begins

Tags

NGSS.HS-PS1-8

What is the relative age of a rock?

• its age based on how much carbon-14 the rock contains

• its age compared to the ages of other rocks

• the number of years since the rock formed

• less that the age of the fossil it contains

Tags

NGSS.MS-ESS1-4

The time it takes for half of the radioactive atoms in a sample of a radioactive element to decay is called

Tags

NGSS.HS-PS1-8

Velociraptors live during the _______________ era

A ______________ fossil forms when dissolved minerals replace the remains of an organism and then harden to form rock

Potassium-40 is useful for dating very old rocks because it has a(n) _______________ of 1.3 billion years

Tags

NGSS.HS-PS1-8

_______________is a gap in the geologic record where some rock layers have been lost because of erosion