Variation and Evolution (NEW)

Question 1

What is Continuous variation?

Answer 1

Controlled by more than one gene and environmental factors such as height and weight.

Question 2

What is discontinuous variation?

Answer 2

Usually controlled by one gene
- so individuals fit clearly into discrete groups such as eye
colour, blood type.

Question 3

What is SEXUAL reproduction?

Answer 3

• Gametes are produced with half of the genetic information of both parents.
• A combination of these gametes at fertilisation produces new offspring
• Offspring show genetic variation are more likely to survive sudden environmental change.

Question 4

What is ASEXUAL reproduction?

Answer 4

• Offspring are produced from 1 parent.
• No energy is wasted on gametes and finding a mate meaning a lot of offspring can be produced quickly
• No genetic variation. Offspring are clones of the parent
• genetically identical

Question 5

What is variation caused by?

Answer 5

• Genetic factors: characteristics that are caused by genes, inherited from parental DNA
• Environmental Factors : characteristics that change due to the environment

Question 6

What is the process of natural selection?

Answer 6

• Mutations: random changes in genes causes variation in species
• Variation : Small differences within a species make some individuals better adapted
  to the environment
• Advantageous: Does it make a species better adapted to their environment. If so it
• Passes
• On
• Genes

Question 7

What is a mutation of a gene?

Answer 7

• A change in a gene

- Some mutations can be inherited and cause disease

Question 8

What does cystic fibrosis do?

Answer 8

• a genetically inherited disease

- causes thick sticky mucus that block bronchioles in the lungs

Question 9

What does GENE THERAPY do to treat CYSTIC FIBROSIS?

Answer 9

-An inhaler can be used to get the gene into lung cells
-But as cells renew the gene is not copied and so new cells do not contain the normal
gene
- (it is a TREATMENT not a CURE)

Question 10

What happens if environmental change is too quick?

Answer 10

If environmental change is too quick for species to adapt by natural selection extinction
may occur.

Question 11

What were the aims oh the Human Genome Project?

Answer 11

• working out the order or sequence of all the three billion base pairs in the human genome
• identifying all the genes
• developing faster methods for sequencing DNA

Question 12

How will the Human Genome Project help medicine?

Answer 12

allow scientists to develop new ways of treating or diagnosing illnesses, especially genetic disorders and cancer

Question 13

What examples are there that evolution is still ongoing?

Answer 13

• Mutations of bacteria produce new strains. Some bacteria might become resistant to certain antibiotics, example of natural selection
• some rats are resistant to warfarin (rat poison)