Old And New Species

Question 1

Where does evidence of early life come from

Answer 1

Fossils

Question 2

What are fossils

Answer 2

Remains of organisms from many years ago found in rocks

Question 3

What 4 ways are fossils formed

Answer 3

Hard parts of animals that do not decay easily
Parts of organisms that have not decayed because of one or multiple conditions needed for decay are absent e.g. Oxygen
When parts of the organism are replaced by other materials as they decay
As preserved traces of organisms e.g. Footsteps, burrows and rootlet traces

Question 4

Why can scientist not be certain about how life started

Answer 4

Forms of life early on we’re soft bodies meaning that they have few traces left behind. Many destroyed by geological activity

Question 5

What do we learn from fossils

Answer 5

How much or little different organisms have changed as life developed

Question 6

What can extinction be caused by

Answer 6

Changes to environment over geological time
New predictors
New more successful competition
New disease
Catastrophic event e.g. Asteroids and volcanos
Cyclical nature of speciation

Question 7

How does a new species arise

Answer 7

Isolation- Two populations of a species become separated e.g. Geographically
Genetic variation- each population have a wide range of alleles that control characteristic
Natural selection- in each population the most suitable allele to their survival is passed on to offspring
Speciation- the populations become so different they can no longer breed successfully