Fossil

Question 1

What are fossils ?
What do fossils show?

Answer 1

Remains of preserved organisms from thousands of years ago, often found in rocks.

Provide evidence that organisms lived ages ago and can tell how much or little organisms have evolved

Question 2

What is the first way fossils form in rocks ?

Answer 2

From gradual replacement by minerals
1) We don’t decay easily and can last a long time
2) They’re eventually replaced by minerals as they decay, forming a rock like substance shaped like the original hard part
3) The surrounding sediments also turn to rock, but, the fossil stays distinct inside the rock and eventually someone digs it up

Question 3

What is the second way fossils form in rocks ?

Answer 3

From cast and impression
1) Sometimes, fossils are formed when an organisms is buried inside a soft material like clay. Clay hardens around it, organisms decays leaving a cast of its self
2) An animals burrow or plant roots can be preserved as casts
3) Things like footprint can be pressed into soft materials leaving an impression when it hardens

Question 4

What is the Third way fossils form in rocks ?

Answer 4

From preservation in places where no decay happens
1) In amber or tarpits where there’s no oxygen or moisture, decay microbes can’t survive
2) in glaciers, too cold so decay microbes can’t survive
3) peat bogs are too acidic for decay microbes

Question 5

Hypothesis on how life first came into being

Answer 5

in a primordial swamp or simple organic molecules bought to earth by comets and became more complex organic molecules - > simple life forms

Question 6

Why can not this hypothesis be proved or disproved ?

Answer 6

Not enough valid evidence regarding
- Early forms of life were soft bodies and soft tissues tend to decay completely = fossil record incomplete
- Fossils formed from millions of years ago have been destroyed by geological activity e.g movement of tectonic plates