SB4b Darwin's theory

Question 1

Who was Darwin and what did he theorise? (5)

Answer 1

.Theologist and self-taught naturalist
.Believed living things evolved
.Suggested evolution happed by natural selection or “survival of the fittest”
.Gathered detailed evidence from voyages (e.g. The Galapagos Islands) to support his theory
.Darwin did not provide an explanation of how features were passed on

Question 2

Variation?

Answer 2

there will be genetic variation between the individuals of any species. This is often caused by mutation.

Question 3

Overproduction?

Answer 3

Most species will produce more young than will survive to adulthood. Some will die some will survive.

Question 4

Struggle?

Answer 4

Struggle for existence – environmental change can lead to a shortage of resources e.g. food, leading to competition for survival between the organisms.

Question 5

Survival?

Answer 5

Those with advantageous variations are more likely to survive this change in the environment. This is ‘survival of the fittest’.

Question 6

Advantageous characteristic inherited?

Answer 6

better adapted organisms are more likely to survive and reproduce successfully passing on the advantageous characteristics to their offspring.

Question 7

Gradual change?

Answer 7

Over a period of time the proportion of individuals with the advantageous characteristics in the population will increase and the population will change, leading to evolution.

Question 8

Mutation?

Answer 8

new genes are a result of the changes in sections of DNA (existing genes).

Question 9

How can mutations occur?

Answer 9

naturally through mistakes when DNA is copied before cell division.

Question 10

What do mutations not change?

Answer 10

the amino sequence so the proteins do not change.