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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What are fossils?

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


What information do fossils give us?

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


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 •


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


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


Formation of fossils:


Fossil tracks formation:


What do fossils show us?

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