CB4 - Natural selection and Genetic modification

Question 1

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

Answer 1

Darwin :
Spent 5 years on a voyage around world studying plants and animals. Noticed that there were variation of same species and characteristics most suited to environment were likely to survive. Noticed characteristics could be passed on to offspring.

Question 2

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

Answer 2

Wallace :
Provided lots of evidence to help support this theory. Noticed that warning colours used to deter predators.

Question 3

What was the impact of the theory on Modern Biology?

Answer 3

Understand life changes through process of evolution and we have descended from a common ancestor. Impacted on classification, antibiotic resistance and conservation.

Question 4

Describe theory of evolution by natural selection?

Answer 4

It is a matter in which variations of some individuals make them better to cope with change and are more likely to survive than others (Survival of the fittest). Survivors breed and pass on the variation to offspring.

Question 5

Explain antibiotic resistant?

Answer 5

Some bacteria are more resistant that others as they may have a mutation or have an allele. Antibiotics ae released, most die but some survive. They will reproduce and the offspring will have the allele on resistant. Over time, there will be a population of resistant bacteria.

Question 6

Describe the evidence for human evolution from Ardi?

Answer 6

Found in Ethiopia and is 4.4 million years old.
The structure of her feet suggests she climbs trees and had ape-like big toe. Had long arms and short legs. Brain size same as chimpanzee’s. Structure suggest walked up straight.

Question 7

Describe the evidence for human evolution form Lucy?

Answer 7

Found in Ethiopia and is 3.2 million yeas old. Had arched feet and more adapted to walk than climbing. Size of arms and legs was between what you would find in humans and apes. Brain was sightly larger that Ardi.

Question 8

Describe the evidence for human evolution form Leakey’s discovery?

Answer 8

Found in Kenya and is 1.6 million years old. Had short arms and long legs, more like humans than apes. Brain size was much larger than Lucy.

Question 9

Describe the evidence for human evolution based on stone tools?

Answer 9

If the tools are simple, it would be older and also look at the structural features. Modern tools would be more sophisticated. Scientist could use stratigraphy (Study layers of rocks).

Question 10

Describe how the pentadactyl limb provides evidence for human evolution?

Answer 10

Pentadactyl limb is a limb with 5 digits. Many species has similar bone structure but diff function. Suggest we have common ancestor.

Question 11

Describe how genetic analysis has led to 3 domains rather than 5 kingdom classification?

Answer 11

Development of genetic analysis show all organism apart from prokaryotic have unused section of DNA.
3 Domains :
- Eukarya have unused section of DNA
- Archae are prokaryotes that have unused section of DNA
- Bacteria are prokaryotes that have NO unused section of DNA

Question 12

Explain selective breeding?

Answer 12

When humans artificially select plants or animals for a particular characteristic.
Selective breeding :
- Select organism with desired characteristics for each gender
- Breed them together
- Select offspring with desired characteristics
- Repeat over generation

Question 13

What is the process of Tissue culture?

Answer 13

1. First choose plant you want to clone
2. Remove several pieces of tissue from plant.
3. Grow tissue in a growth medium. Done under aseptic conditions.
4. After a while, move to potting compost

Question 14

What are the advantages of Tissue culture?

Answer 14

• Produces many identical plants
• Preserve species
• Produce plants that are hard to grow

Question 15

What is the process of Genetic engineering?

Answer 15

1. DNA is cut with restriction enzyme. Vector DNA is cut with same restriction enzyme
2. Vector DNA and DNA is left with sticky ends. They are mixed with ligase enzyme
3. Ligase join both DNA to make recombinant DNA
4. New DNA is inserted in cell

Question 16

What are the Advantages and Disadvantages of producing GM organisms?

Answer 16

Advantages:
- Helps to treat diseases
- Produce crops with beneficial effects
- Produces crops that are drought resistant
Disadvantages:
- Long term affect to biodiversity
- GM seeds are more expensive
- Need special equipment

Question 17

What are the Advantages and Disadvantages of agricultural solution to demands of growing human population?

Answer 17

Advantages:
- Natural enemies introduced to environment are capable of sustain themselves
- Mostly always effective
- Can control insect and weeds
Disadvantages:
- Can’t control what you set lose in ecosystem
- Slow process
- Expensive to set up

Question 18

What are the advantages and disadvantages of GE in agriculture and medicine?

Answer 18

Advantages:
- GM is faster and more efficient
- Improves crop yield and quality
- Insect and pest resistance can be developed and inserted in plants
Disadvantages:
- Not ethical
- GM crop seeds are expensive
- GM crops could be harmful
- GM crops could cause allergic reaction