Lesson 15: Fossils/ Extinction

Question 1

Give 3 sources of evidence for The Theory of Evolution.

Answer 1

1.) It has been shown that characteristics are passed on to offspring in genes.
2.) Further evidence in fossil records
3.) Further knowledge on how resistance to antibiotics evolves in bacteria.

Question 2

What are “fossils?”

Answer 2

• Fossils are remains of organisms from millions of years ago, which are found in rocks.

Question 3

What are the 3 different ways that fossils may be formed?

Answer 3

Fossils may be formed:
* from parts of organisms that have not decayed because one or more
of the conditions needed for decay are absent.
* when parts of the organism are replaced by minerals as they decay.
* as preserved traces of organisms, such as footprints, burrows and
rootlet traces.

Question 4

Why can scientists not be certain about how life began on Earth?

Answer 4

• Many early forms of life were soft- bodied organisms, which means they left few traces behind.
• What traces there were (of these soft- bodied organisms) have mainly been destroyed by geological activity.

Question 5

What can we learn from fossils?

Answer 5

• From fossils, we can learn how little or how much different organisms have changed as life devloped on Earth.

Question 6

When do extinctions occur?

Answer 6

• Extinctions occur when there are no remaining individuals of a species
  still alive.

Question 7

What are the 4 different reasons as to why a species may become extinct?

Answer 7

• A catastrophic event ie. astreoid colliding with Earth leading to extinction of dinasours.
• Environmental changes ie. change in weather patterns.
• New disease/ new predator (may kill all individuals of a species.)
• A new more succesful species evolves and competes with the species for resources. ie. scarce food or water.