Unit 2 Section 1- Variation

Question 1

What is interspecific variation?

Answer 1

Differences between species

Question 2

What is intraspecific variation?

Answer 2

Differences within a species

Question 3

What causes intraspecific variation?

Answer 3

Genetic and environmental factors

Question 4

How do genetics cause intraspecific variation?

Answer 4

All organisms within a species have the same genes but inherit different alleles. Different alleles= different genotype a which means there is variation in phenotype

Question 5

How does environment cause intraspecific variation?

Answer 5

Phenotype is affected by environmental factors eg:
Plant growth is different with the amounts of minerals available
Identical twins are genetically the same but can grow to be different due to different illnesses

Question 6

Variation is usually a mix of environmental and genetic factors give an example

Answer 6

Someone may have the gene to grow 6ft tall but this is affected by their diet and health
The amount of melanin which determines skin colour is controlled by genes however skin colour is influenced by amount of sunlight

Question 7

Explain what causes variation between the species and within the species? (4 marks)

Answer 7

Between species variation is due to genes. Variation within a species can be due to genetic or environmental factors. Different alleles cause genetic differences. Environmental factors affect how the same genes are expressed in their appearance.
Ref: pg47 exam Q

Question 8

How can we ensure that a sample used to study variation in a population of representative?

Answer 8

Random selection to avoid bias

Statistical tests to show the results aren’t due to chance

Question 9

What does the mean tell us?

Answer 9

The average value

Question 10

What is standard deviation?

Answer 10

Variation of values about the mean