Topic Four - Variation and Evolution

Question 1

What is variation?

Answer 1

Variation is how organisms differ. It can be caused by our genes or the environment in which we live.

Question 2

Give an example of variation.

Answer 2

Eye colour is due to genes because we have inherited them. Scars/Tattoos would however be due to environmental variation.

Question 3

Give examples of genetic variation.

Answer 3

Eye colour
Tongue rolling
Skin colour
Natural hair colour
Shoe size
Height
Weight

Question 4

Give examples of environmental variation.

Answer 4

Scars
Hair length
Dyed hair colour
Tattoo
Nail varnish colour
Height
Weight

Question 5

What is continuous variation?

Answer 5

If variation can take any value (e.g. height)

Question 6

What is discontinuous variation?

Answer 6

If measurements fall into categories (e.g. shoe sizes).

Question 7

Give examples of continuous and discontinuous variation.

Answer 7

CONTINUOUS -
Height
Weight
Length of hair
Foot length

DISCONTINUOUS -
Shoe size
Eye colour
Tongue rolling

Question 8

Why do some animals vary in colour?

Answer 8

To camouflage from prey.

Question 9

Describe Sexual Reproduction

Answer 9

2 parents are needed
Lots of variation in the offspring
Offspring are genetically different to the parents.

Question 10

Describe asexual reproduction.

Answer 10

1 parent needed
No variation in the offspring
Offspring are genetically identical to the parent and each other - they are called clones.

Question 11

What is a mutation?

Answer 11

A mutation is a charge that can occur in a gene (in DNA)
A mutation will occur at random and may create new genes.
Mutations can be harmful or of benefit.

Question 12

Why would a mutation for big ears in rabbits be helpful?

Answer 12

Hearing predators

Question 13

What type of scans can increase your mutations risk?

Answer 13

X-rays or CT scans
UV.

Question 14

Give one disease that can be caused by DNA mutations.

Answer 14

Skin cancer / cancer

Question 15

Can mutations be passed down?

Answer 15

If changes occur in normal body cells, the changes are lost when we die. But, if the changes occur in our sex cells such as sperm, there is the possibility that the changes in the gene will be passed down onto the next generation.

Question 16

What is Cystic Fibrosis?

Answer 16

Cystic Fibrosis is an inherited disorder that affects the cell membranes, causing the production of thick and sticky mucus.
It is caused by a mutated gene. Both parents must have the mutated gene for a child to have Cystic Fibrosis (punnet square - 25%)

Question 17

What is Gene Therapy?

Answer 17

Gene therapy involves inserting copies of a normal allele into the chromosomes of an individual who carries a faulty allele. The normal allele can be breathed in using an inhaler.
It is not always successful, but as advances in technology are made it is likely to be successful in the future.

Question 18

Who created the theory of Natural selection?

Answer 18

Alfred Russell Wallace and Charles Darwin over 150 years ago

Question 19

What is Natural Selection?

Answer 19

Certain individuals gain an advantage over other individuals they are in competition with. This animal is therefore more likely to survive and breed.

Question 20

How do you answer a natural selection question?

Answer 20

MARG
Mutation
Advantage
Reproduce
Genes passed on

Question 21

What could occur if evolution doesn’t happen?

Answer 21

Extinction.

Question 22

How did rats mutate to Warfarin.

Answer 22

Warfarin is rat poison. One rat mutated to be resistant to Warfarin, therefore is more likely to reproduce and pass. Makes rats harder to kill.

Question 23

Explain antibiotic resistance.

Answer 23

1. A few bacteria are resistant to antibiotics.
2. Antibiotic is applied.
3. Most susceptible bacteria is killed.
4. Bacteria multiply.
5. Antibiotic is applied again.
6. The few remaining susceptible bacteria are killed and the resistant bacteria multiply.
7. Antibiotic is now ineffective against the resistant bacteria.

Question 24

What is a genome?

Answer 24

Name given to all the genetic information in an organism. It includes all the genes and their sequence on all the chromosomes and the DNA base pairs that make up those genes.

Question 25

What is the human genome project?

Answer 25

International scientific research project that worked out the sequence of chemical base pairs in human DNA, identified all the genes (and their variants) in humans and their location on the chromosomes. 2003.