B2 6 Old and New Species Flashcards Preview

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Flashcards in B2 6 Old and New Species Deck (8)
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1

What are fossils?

Fossils are the remains of organisms from many years ago that are found in rocks

2

What information do fossils give us?

Fossils give us information about organisms that lived millions of years ago. Eg: dinosaurs

3

How do fossils form?

• From hard parts of an animal. These are the bits that don't decay easily. Eg: bones, teeth, claws or shells • When an animal or plant does not decay easily. This happens if one or more of the conditions needed for decay are not present Examples: little or no oxygen, poisonous gases kill off bacteria, low temp • When harder parts of the animal or plant are replaced by other minerals. Most common type of fossils • Traces left behind by animals. Eg: fossil footprints, burrows, rootlet traces and droppings •

4

Ice fossils:

• Rare • Gives clear insight into what an animal looked like • Tell us what an animal had been eating • DNA can also be extracted and compared to modern organisms

5

Why is the fossil record not complete?

• Many of the earliest life forms were soft-bodied organisms = little fossil trace left behind • = little valid evidence of how life began • Most organisms that died did not become fossilised. The right conditions for fossil formations were rare • Fossils also destroyed by geological activity • Rock broken down, worn away, buried and melted over years • Fossils yet to be found

6

Formation of fossils:

7

Fossil tracks formation:

8

What do fossils show us?

Fossils show us how much or how little organisms have changed as life has developed on earth