Topic 4 - Natural Selection & Genetic Modification

Question 1

Describe the work of Darwin and Wallace in the development of the theory of evolution by natural selection

Answer 1

• While travelling independently, they notices there was variations in species in different areas

Question 2

The Process of Natural Selection (Darwin’s Theory)

Answer 2

1. Random mutations occur
2. Compete to survive
3. Survival of the fittest
4. Survivors reproduce to pass on alleles
5. Alleles are more common in population

Question 3

Explain how antibiotic resistance in bacteria support Darwin’s theory

Answer 3

1. Random mutations in bacteria occur
2. Compete to survive
3. Survival of the fittest
4. The bacteria which survive divide to pass on alleles
5. Alleles are more common in population, bacteria continue living

Question 4

Ardi

Answer 4

• Had a small brain size
• Hands and feet adapted for both tree-climbing and bipedal walking.
• Lived 4.4 million years ago.

Question 5

Lucy

Answer 5

• Walked upright
• Long arms and a small brain
• Lived 3.2 million years ago.

Question 6

Leakey’s discovery of fossils

Answer 6

• Attributed to Homo habilis
• Larger brain size compared to earlier
• Evidence of early tool use.

Question 7

Describe the evidence for human evolution based on stone tools

Answer 7

As time went on:
- they became more complex
- older were found further underground
- they had different carbon amounts

Question 8

How does the pentadactyl limb provide evidence for evolution

Answer 8

• Although they have all evolved for different purposes, they all have the same basic layout

Question 9

5 Kingdoms of Classification

Answer 9

• Prokaryotes
• Protists
• Fungi
• Plant
• Animal

Question 10

3 Domains

Answer 10

• Archaea
• Eukaryota
• Bacteria

Question 11

Impact on food plants and domesticated animals due to selective breeding

Answer 11

• Selection of desired traits
• Resistance to pests and diseases
• Improved quality

Question 12

Selective breeding

Answer 12

• Select individuals with desirable characteristics and breed them together

Question 13

Process of tissue culture

Answer 13

• Small pieces of organisms (‘tissues’) are grown (‘cultured’) using nutrient media (artificial growth medium)

Question 14

Advantages of tissue culture

Answer 14

• Disease Elimination (in plants)
• Rapid Multiplication

Question 15

Genetic Modification

Answer 15

• Modifying the genome of an organism to introduce desirable characteristics

Question 16

Restriction enzymes in Genetic Modification

Answer 16

• Cuts the backbones of double bonds, separating the bonds themselves

Question 17

Sticky ends in Genetic Modification

Answer 17

• The single-strand overhangs due to restriction enzymes

Question 18

Ligase in Genetic Modification

Answer 18

• Sticks together the sticky ends and the genetically cut bacterium plasmid with same DNA code

Question 19

Vectors in Genetic Modification

Answer 19

• Delivers foreign DNA into a host organism

Question 20

Advantages of genetic engineering to produce GM organisms:

Answer 20

• Mass production
• Future visions like animal organs for human transplants
• Modify crops to suit environment

Question 21

Disadvantages of genetic engineering to produce GM organisms:

Answer 21

• Difficult to predict effects
• Ethical concerns if used on humans
• Genes from GM organisms can get into environment

Question 22

Advantages of the agricultural solution:
- Fertilisers

Answer 22

• Increased Crop Yields
• Resistance to disease
• Year-round production

Question 23

Disadvantages of the agricultural solution:
- Fertilisers

Answer 23

• Environmental Pollution
• Soil Degradation
• Cost to Farmers

Question 24

Advantages of the agricultural solution:
- Biological Control

Answer 24

• Reduced Pesticide Dependency
• Long-Term Sustainability
• Enhanced Biodiversity

Question 25

Disadvantages of the agricultural solution:
- Biological Control

Answer 25

• Only sometimes gets desired result
• Time and Research Investment
• Risk of Non-Target Effects

Question 26

Advantages of Selective breeding and Genetic Modification

Answer 26

• Agriculture benefits like higher yield
• Medicine

Question 27

Disadvantages of Genetic Modification

Answer 27

• Transferring genes to wild population risk
• Ethical issues (modifying embryos)

Question 28

Disadvantages of Selective Breeding

Answer 28

• Reduced Genetic Diversity
• Ethical issues (forced to breed, and compromise their wellbeing