TEKS 5.7D Identify fossils as

evidence of past living organisms and the

nature of the environments as the time using models.

Study the diagram below.

1

2

soilsandstone

conglomerateshale

limestone

Fossil 1 is probably….A. Younger than fossil

2

B. Older than fossil 2

C. Formed in metamorphic rock

D. Formed in igneous rock

1

2

soilsandstone

conglomerate

shale

limestone

The correct answer is A. Fossil number 1 is

younger than fossil number 2. The bottom layer of rock (limestone) formed before the layer of shale. Fossil 1 is in the shale.

1

2

soilsandstoneconglomerateshale

limestone

B, C, and D are incorrect

B The layer of limestone was formed before the layer of shale.

C Sandstone, conglomerate, shale, and limestone are sedimentary rocks.

D. Fossil number 1 is in shale which is a sedimentary rock.

B. Older than fossil 2

C. Formed in metamorphic rock

D. Formed in igneous rock

because

12

soilsandstoneconglomerateshalelimestone

Fossils were found in these four layers of rock.

1

2

4

3

A. Each layer shows evidence of a different environment

B. Mammals dominated the environment

C. The environment has always been dry

D. Some layers show wet environments and others show dry environments

What can you tell about this environment over

time?1

2

4

3

The correct answer is D. Layer 1, 3, and 4

are wet environments.

Layer 2 is most likely a dry environment.

1

2

4

3

The most likely place to find a fossil is in ________

rock.A

B

smooth rock

rough rock

volcanic rock

Sedimentary rock

D

C

A

B

The correct answer is A.

Most fossils form when a dead plant or animal is buried quickly by sediments. As the sediments harden the remains become trapped in rock and form a fossil.

Sedimentary rock

A

These answers are incorrect because …

Sedimentary rock can be rough or smooth depending on how much and how it has been weathered.

Volcanic rock from

lava flow produces a lot of heat and pressure that will destroy living material so a fossil cannot form.

Smooth rock

Rough rock

Volcanic rockD

C

B

Answers B, C, and D are wrong.

What can you infer about an animal from a fossil of its

jawbone?

A. How big its feet were

B. Whether it walked on four or two legs

C. The approximate size of the animal from which it

came

D. Whether it was a herbivore, carnivore, or

omnivore

The correct answer is C.The size of the jawbone would indicate the approximate size of the animal from which it came. If teeth were in place, they would indicate what the animal ate. The jawbone could also give clues to the size and shape of the animal’s head.

These answers are incorrect because …

A. The jawbone will not indicate the size of the feet of the animal.

B. You would need fossils of the feet or fossils of the track of the animal to determine the number of feet.

C. The teeth would have to be in place to indicate what the animal ate.