B14 - Variation and Evolution

Question 1

What is variation?

Answer 1

• Variation is the differences in the characteristics of individuals in a population.
• Genetic (Nature) and Environmental (Nurture)

Question 2

Explain how beneficial characteristics can become more common in a population over time.

Answer 2

=> Variation due to random mutations
=> Natural Selection (some individuals have beneficial characteristics)
=> More likely to survive
=> Breed and reproduce
=> Offspring inherit beneficial characteristics.

Question 3

What is selective breeding?

Answer 3

Humans artificially select animals or plants that are going to breed so that the genes for a particular characteristic remain in the population.

Question 4

What is genetic engineering?

Answer 4

To transfer a gene responsible for a desirable characteristic from one organism’s genome into another organism, so that it also has the desirable characteristic.

Question 5

How might farmers use selective breeding?

Answer 5

• Animals that have high produce yield (e.g. meat, milk)
• Crops with disease resistance
• Dogs with a good, gentle temperament
• Decorative plants with big or unusual flowers

Question 6

How can embryo transplants be used to create clones?

Answer 6

=> Early embryo removed from mother
=> Embryo split into cells in lab
=> Cells allowed to grow into identical embryos
=> Identical embryos transferred into host mother who has been given hormones
=> Identical clone born who is not biologically related to their host mother

Question 7

Give three way scientists use genetic engineering.

Answer 7

• Bacteria have been genetically modified to produce human insulin that can be used to treat Type 1 diabetes
• Genetically Modified (GM) crops to improve size/quality of fruit; resistant to disease, insects and herbicides
• Sheep have been genetically engineered to produce substances, like drugs, in their milk that can treat human diseases
• Gene therapy for people with inherited diseases (e.g. inserting working genes into patients)

Question 8

How many parents does embryo cloning involve?

Answer 8

• 1 father

- 2 mothers

Question 9

Describe the process of adult cell cloning.

Answer 9

=> ANIMAL A: adult cell (e.g. skin) removed
=> Nucleus removed
=> ANIMAL B: mature egg cell removed
=> Nucleus removed from egg cell
=> Nucleus from ANIMAL A inserted into ANIMAL B egg cell
=> Small electric shock stimulates egg to divide
=> Embryo is inserted into ANIMAL C
=> Identical clone of ANIMAL A is produced

Question 10

How many parents does adult cell cloning involve?

Answer 10

• 0 fathers
• 3 mothers
  OR
• 1 father
• 2 mothers
  (depends of desired gender of clone)