The fossil record (GW3)

Question 1

What are fossils?

Answer 1

The remains of dead organisms.

Question 2

How can we out how old fossils?

Answer 2

By measuring the radioactivity of the rock.

Question 3

Why are fossils rare?

Answer 3

Most dead organisms disintegrate when they decay.

Question 4

Sometimes when the hard parts of an animal are covered by mud. These parts are slowly replaced by ____ which takes exactly the same shape eventually, the mud forms _____ rock.

Answer 4

Minerals Sedimentary

Question 5

Most fossils are imprints that show the shape of ____, bones or leaves.

Answer 5

Shells

Question 6

How do fossils give us evidence of evolution?

Answer 6

The earth consists of layers of rock. The fossils in each layer act as a record of the life that existed at the time. The more recent fossils will be in rock layers nearer the surface.

Question 7

What does a fossil record show us? (4)

Answer 7

-The variety of life on Earth today did not arise all at once -The first life was in wate— life on land came much later -As each new type of animal evolved, the older ones declined—these less adapted organisms often become extinct. -Some fossils give us clues as to how a particular group evolved.

Question 8

What does the Archaeopteryx show us?

Answer 8

That birds and reptiles evolved from a common ancestor.

Question 9

Why is the Grand Canyon important in terms of evolution?

Answer 9

The sides of the Grand Canyon are eroded by the Colorado River. The soft sedimentary rock reveals invertebrates in the lower layers. These layers are 2000 million layers old. In the layers above a range of vertebrates are found.

Question 10

Each layer of rock builds up a story of how each group of animals ____.

Answer 10

Evolved

Question 11

• 500 million years ago there were members of all the main ____ groups living.
• The first vertebrates to evolve were the ___. These appeared about 400 million years ago.
• About 300 million years ago life moved onto land. _____ were thought to be the first land vertebrates.
• ____ evolved from an ancient type of amphibian about 200 million years ago.
• About 200 million to 65 million years ago was the age of the ___The world was dominated by these reptiles before they suddenly became extinct 60 million years ago.
• ____ and ____ appeared about 65 million years ago.
• The first of our ape-like ancestors lived six million years ago. Fossil evidence from the Rift Valley shows that they were able to walk ___.

Answer 11

Invertebrate

Fish

Amphibians

Reptiles

Dinosaurs

Birds and Mammals

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