Fossils

Question 1

what are fossils?

Answer 1

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

Question 2

what are the three ways that fossils are formed?

Answer 2

Gradual replacement, casts and impressions, and preservation

Question 3

how does gradual replacement work?

Answer 3

1. Parts of the organism such as teeth, shells and bones etc. which don’t decay easily last a long time when buried
2. They are eventually replaced by my minerals as they decay forming a rock like substance shape like the original hard part
3. The surrounding sediment also turns to rock but the fossil stays distinct inside the rock and eventually it is found

Question 4

how do casts and impressions work?

Answer 4

1. Sometimes fossils are buried in a soft matter like clay, the clay then later hardens around it and the organism decays, leaving a cast of itself
2. Things such as footprints can be pressed into a soft material leaving an impression when it hardens

Question 5

how does preservation work?

Answer 5

In area that are not suitable for decay because the conditions are too extreme the decay microbes cannot exist

1. In amber and tar pits there is no oxygen or decay moisture so decay can not survive
2. In glaciers its too cold for the decay microbes to work
3. Peat bogs are too acidic for decay microbes

Question 6

how do people think that life began?

Answer 6

People think that life started when comets bought simple organic molecules to earth which may have then have turned to more complex molecules then eventually simple life forms that evolved into the life forms now

Question 7

why can scientists not confirm how life began?

Answer 7

As the fossil evidence is only very slight as scientists think that most animals were soft bodied and therefore most of there bodies have decayed away completely and so the record is incomplete