4.6.2.1 Variation

Question 1

What does the phenotype an organism has depend on?

Answer 1

• genotype (genes it inherited)
• environment (the place it lives in)

Question 2

Why does the phenotype depend on the genotype?

Answer 2

• genes are passed on from parents in sex cells
• combining of genes from the mother and father creates genetic variation
• only identical twins have same genotype
• lots of genetic variation

Question 3

Why does the phenotype depend on environment?

Answer 3

• conditions the organism grows and develops in also affects its appearance
• e.g scars, smaller and yellow leaves in plants

Question 4

What can characteristics sometimes result from?

Answer 4

• combination of genetics and environment, e.g. weight

Question 5

Why is weight affected by environment and genetics?

Answer 5

• depends on the food you eat but also how quickly your body breaks it down and how much it stores as fat depends on your genes
• depends on the food you eat

Question 6

How is genetic variation introduced?

Answer 6

• mutations in sequence of DNA which occur continuously

Question 7

What does genetic variation do towards phenotypes?

Answer 7

• most have no effect on them
• some will influence phenotype but it is unlikely that it will bring about a new phenotype
• if mutation does determine phenotype and is advantageous, natural selection will mean it becomes the common phenotype relatively quickly