Fossils And Extinction

Question 1

Fossils form rocks in which three ways?

Answer 1

1) from gradual will replacement by minerals
2) from casts and impressions
3) from preservation in places where no decay happens

Question 2

How are fossils formed from gradual replacement by minerals? (3)

Answer 2

The parts of the organism which don’t decay easily are eventually replaced by minerals as they decay. This forms a rocklike substance shaped like the original hard part. The surrounding sediments also turn to rock but the fossil stays distinct inside the rock until it is found.

Question 3

How are fossils formed from casts and impressions?

Answer 3

When an organism is buried in a soft material likely the clearly hardens around it and the organism decays, leaving a cast of itself

Question 4

How are fossils formed from preservation in places where no decay happens?

Answer 4

In Amber and carpets there is no oxygen or moisture so decay microbes cant survive. In glaciers it’s too cold for the decay microbes to work.
Peat Boggs are too acidic for decay microbes

Question 5

What do fossils show?

Answer 5

Fossil show how many of today’s species have evolved over millions of years

Question 6

Why can’t the hypotheses’ of where the first living things come from be supported or disproved?

Answer 6

Because there is a lack of valid and reliable evidence

Question 7

Why do scientists believe there is a lack of evidence of where the first living things came from?

Answer 7

Because scientists believe many early organisms were softbodied, and soft tissue tends to decay completely so the fossil record is incomplete.

Question 8

When does Extinction happen?

Answer 8

Extinction happens if you can’t Evolve quickly enough

Question 9

What are fossils?

Answer 9

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

Question 10

What are the six reasons as to why species become extinct?

Answer 10

1) The environment changes to quickly
2) A new predator kills them all
3) A new disease kills them all
4) they can’t compete with another species for food
5) it catastrophic event happens that kills them all
6) can you species develops

Question 11

What is speciation?

Answer 11

Speciation is the development of a new species

Question 12

What is the definition of species?

Answer 12

Species is a group of similar organisms that can reproduce to give fertile offspring

Question 13

When does speciation occur?

Answer 13

Speciation occurs when populations of the same species become so different that they can no longer breed together to produce fertile offspring

Question 14

What two things lead to speciation?

Answer 14

Isolation and natural selection

Question 15

What is the definition of isolation?

Answer 15

Isolation is where populations of the species are separated

Question 16

How does a different environment caused by isolation create speciation?

Answer 16

If the environment is different on each side different characteristics will become more common in each population due to natural selection eventually the population will have changed to the point they are unable to produce fertile offspring

Question 17

Give an example of something that can be preserved as a cast

Answer 17

animals burrow
A plants roots
A footprint

Question 18

Some fossils of early organisms did form in ancient rocks. Explain why many of these fossils have not survived to the present day

Answer 18

Some fossils are destroyed in geological activity such as the movement of tectonic plates which may have crossed fossils already formed in the rocks

Question 19

Explain why the remains of an insect has been preserved so well inside the amber

Answer 19

Inside the amber there is no oxygen or moisture so the insect remains can’t decay as the microbes can’t survive

Question 20

Briefly explain how the fossil of teeth is formed

Answer 20

Teeth don’t decay easily so they can last a long time when buried. They are eventually replaced by minerals as they decay leaving you rocklike substance in the shape of the teeth