Rock Correlation & Index Fossils

According to the Law of Superposition, the oldest fossils are found

• at the top of the rock layers

• in the bottom rock layers

• in the middle of the rock layers

• somewhat near the surface

Answer explanation

According to the Law of Superposition, in undisturbed rock layers, the oldest fossils are found in the bottom rock layers, while younger fossils are located above them. Therefore, the correct answer is 'in the bottom rock layers'.

Tags

NGSS.MS-ESS1-4

NGSS.MS-LS4-1

Which rock layer contains the youngest fossils?

• F

• E

• B

• C

Answer explanation

Layer F contains the youngest fossils because, in geological terms, the youngest layers are typically found at the top of the sequence. Therefore, F is the correct choice for the layer with the youngest fossils.

Tags

NGSS.MS-ESS1-4

NGSS.MS-LS4-1

Which fossil is the oldest?

• Trilobite

• Ammonite

• Crinoid

• Gastropod

Answer explanation

The trilobite is the oldest of the listed fossils, dating back to the Cambrian period, around 521 million years ago. In contrast, ammonites, crinoids, and gastropods appeared later in the geological timeline.

Tags

NGSS.MS-ESS1-4

NGSS.MS-LS4-1

Which rock layer in the diagram seems to be the oldest?

• F

• E

• B

• A

Answer explanation

Layer A is the oldest because, in geological formations, the principle of superposition states that lower layers are older than those above them. Therefore, since A is at the bottom, it is the oldest rock layer.

Tags

NGSS.MS-ESS1-4

To be considered an index fossil, it must have lived for a relatively short period of time.

• True

• False

Answer explanation

True. An index fossil must have existed for a relatively short time span, allowing it to be used for dating and correlating the age of rock layers.

Tags

NGSS.MS-ESS1-4

NGSS.MS-LS4-1

To be considered an index fossil, it must have been abundant (commonly found).

• True

• False

Answer explanation

True. An index fossil must be abundant and commonly found in various geological formations, which helps in dating and correlating the age of rock layers.

Tags

NGSS.MS-ESS1-4

NGSS.MS-LS4-1

To be considered an index fossil, it must have a wide geographic distribution (found in many locations around the world).

• True

• False

Answer explanation

True. An index fossil must have a wide geographic distribution, meaning it is found in many locations around the world, which helps in correlating the age of rock layers.

Tags

NGSS.MS-ESS1-4

NGSS.MS-ESS2-3

The best index fossils have which two traits?

• widespread geographically, long lifespan

• widespread geographically, short lifespan

• specific place, long lifespan

• specific place, short lifespan

Answer explanation

The best index fossils are widespread geographically and have a short lifespan. This allows them to be used effectively for dating and correlating the age of rock layers across different regions.

Tags

NGSS.MS-LS4-1

During which time period did the first fishes appear?

• Cambrian

• Paleozoic

• Mesozoic

• Cenozoic

Answer explanation

The first fishes appeared during the Cambrian period, which is known for the emergence of many marine life forms, including early fish species. This predates the Paleozoic, Mesozoic, and Cenozoic eras.

Tags

NGSS.MS-LS4-1

How old do Paleontologists believe the Earth is?

• 2015 years old

• 3.6 billion years old

• 4.6 billion years old

• 4.6 million years old

Answer explanation

Paleontologists estimate the Earth is approximately 4.6 billion years old, based on evidence from radiometric dating of the oldest rocks and meteorites. This makes 4.6 billion years old the correct answer.

Tags

NGSS.MS-ESS1-4