Fossils

Question 1

What are fossils?

Answer 1

Remains of plants and animals

Question 2

How are fossils formed?

Answer 2

1. From gradual replacement by minerals
2. From casts and impressions
3. From preservations in places where no decay happens

Question 3

How are fossils formed from gradual replacement by minerals?

Answer 3

1. Things like teeth, shells and bones don’t decay easily so can last a long time when buried
2. They’re eventually replaced by minerals forming a rock like supstance shaped like the original hard part
3. Surrounding sediments also turn to rock but the fossils stays distinct

Question 4

How are fossils formed from casts and impressions?

Answer 4

1. When organisms are buried in a soft material like clay it hardens around it and organism decays leaving a cast of itself
2. Things like footprints can be pressed into these materials when soft leaving an impression

Question 5

How are fossils formed from preservation?

Answer 5

1. In amber (stone) and tar pits there’s no oxygen or moisture so decay microbes can’t survive
2. In glaciers it’s too cold for microbes to work
3. Peat bogs are too acidic for decay microbes

Question 6

What are the hyoptheses explaining how life formed?

Answer 6

1. Firsts life forms came into existence in a primordial swamp here on earth
2. Simple organic molecules were brought to earth on comets
   - BUT; There is a lack of valid and reliable evidence