Fossils (4)

Question 1

• _____ fossils are fossils of sea creatures that became extinct 65 million years ago.
• They lived in a ____ environment
• Therefore other ____ found in the same rock must have been in a marine environment

Answer 1

Ammonite

Marine

Fossils

Question 2

What are fossils?

Answer 2

The remains of living organisms preserved in sedimentary rocks.

Question 3

Why are fossils important?

Answer 3

They provide us with a valuable record of the history of life on Earth

Question 4

• Study of fossils is called _____
• A paleontologist is a ____ who studies the fossil records of extinct organisms

Answer 4

Paleontology

Scientist

Question 5

Where do you find fossils? (2)

Answer 5

• In sedimentary rocks (eg. Sandstone and shale)
• Sedimentary rocks are formed at temperatures and pressures that do not destroy fossils

Question 6

How do sedimentary rocks form?

Answer 6

Question 7

What is the process of fossilization? (8)

Answer 7

1. An animal dies and sinks to the bottom of the river or lake. It is covered with sediment.
2. Anaerobic conditions occur (therefore no decomposition)
3. Covering of sediment must be fast (reducing oxygen levels and slowing down decay)
4. Hard parts of animal replaced with minerals or
5. Dissolve leaving an impression of the natural form
6. The cavity of the impression can also be filled with minerals leaving a mold
7. Whole organisms can be kept intact (eg insects trapped in amber)
8. Pressure builds upon the lower sediments as more sediments accumulate, exposing the skeleton to high pressures and temperatures

Question 8

How long does it take for a bone to fossilize?

Answer 8

10 000 years or more

Question 9

What is South Africa very cool?

Answer 9

• The oldest proof of life on earth
• The oldest multicellular organisms and the most primitive land plants
• The oldest ancestors of the dinosaurs
• The most complete record of the origin of mammals
• An incredible record of the origin of mankind

Question 10

How do fossils form? (3)

Answer 10

Mineralization

Permafrost/Tar/Amber

Trace

Question 11

What are the types of fossils?

Answer 11

• Body fossil
• Moulds
• Trace fossils
• Unchanged fossils

Question 12

Explain mineralization.

Answer 12

Bones and other hard parts are replaced by minerals carried in
solution by groundwater.

Question 13

Explain Trace Fossils.

Answer 13

Trace fossils are fossils that show the organism interacted with its environment. eg. Footprints

Question 14

Explain Mould-Fossils.

Answer 14

A fossil formed when sediment fills the inside or covers the outside of a dead organism and the organism’s remains do not persist, leaving just the shape and texture of the rock to indicate the organic material that was there.

Question 15

Explain body fossils.

Answer 15

Fossils, such as shells and bones, are called ‘body’ fossils because they represent the actual remains of the animal

Question 16

What are unchanged fossils?

Answer 16

Fully preserved fossils, such those frozen.

Question 17

Where else do fossils form?

Answer 17

In areas that experience sub-zero temperatures for most of the year, organisms may be preserved in frozen soil or ice.

Question 18

Only ___% of all organisms that ever lived are fossils

Answer 18

0.1

Question 19

Most fossils are from ____ organisms where sedimentation occurs more readily.

Answer 19

Aquatic

Question 20

What is the Archaeopteryx fossil?

Answer 20

Question 21

Why are fossils so important? (5)

Answer 21

• Show trends in biodiversity
• Show the variety of life on Earth today did not arise all at once
• Show evolutionary relationships (and understand more about the origin of modern species)
• Helps us understand environmental changes
• Helps us to identify where economically important minerals are: coal, oil, and minerals

Question 22

As each new type of animal evolved, the older ones ____.

Less well-adapted animals became ____.

Answer 22

Decline

Extinct