3.2.6 Variation

Question 1

What is variation defined as

Answer 1

Variation is defined as differences between individuals of the same species

Question 2

Variation can be divided into two types depending on what?

Answer 2

how you are able to group the measurements

Question 3

What is Continuous variation

Answer 3

Continuous variation is when there are very many small degrees of difference for a particular characteristic between individuals and they are arranged in order and can usually be measured on a scale

• Examples include height, mass, finger length etc. where there can be many ‘in-between groups

Question 4

What is Discontinuous variation

Answer 4

Discontinuous variation is when there are distinct differences for a characteristic

• For example, people are either blood group A, B, AB or O; are either male or female; can either roll their tongue or not – there are no ‘in-betweens’

Question 5

When graphs of these data are plotted, continuous variation gives, what?

Answer 5

gives smooth bell curves (a result of all the small degrees of difference)

Question 6

When graphs of these data are plotted, Discontinuous variation gives what?

Answer 6

a ‘step–like’ shape

Question 7

Phenotypic variation can be caused in two main ways, what are they?

Answer 7

It can be genetic – controlled entirely by genes

Or it can be environmental – caused entirely by the environment in which the organism lives

Question 8

Describe the 5 processes of Genetic Variation

Answer 8

1. Meiosis creates genetic variation between the gametes produced by an individual

Question 9

Give 5 examples of genetic variation

Answer 9

1. Blood group

Question 10

What are environmental factors

Answer 10

Characteristics of all species can be affected by environmental factors such as climate, diet, accidents, culture and lifestyle

Question 11

Give examples of environmental factors

Answer 11

1. An accident may lead to scarring on the body

Question 12

Discontinuous variation is usually caused by, what?

Answer 12

genetic variation alone

Question 13

Continuous features often vary because of what?

Answer 13

a combination of genetic and environmental causes

Question 14

Give an example of a combination of genetic and environmental causes

Answer 14

1. Tall parents will pass genes to their children for height

• Another way of looking at this is that although genes decide what characteristics we inherit, the surrounding environment will affect how these inherited characteristics develop