Key Area 3.2: Plant And Animal Breeding

Question 1

What is selective breeding?

Answer 1

Animal and plant breeders want to breed organisms together to produce the best characteristics.

Question 2

What characteristics are selected by breeders in crops and animals?

Answer 2

Increased yield
Increased nutritional value 
Pest resistance 
Possession of useful characteristics 
Resistance to disease 
Ability to thrive in damp and cold conditions.

Question 3

What are the steps in selective breeding?

Answer 3

1. Decide which characteristics are important
2. Choose parents that show these characteristics
3. Select best offspring from parents to breed the next generation.
4. Repeat the process continuously.

Question 4

What are the 2 types of selective breeding?

Answer 4

1. Out breeding

2. Inbreeding

Question 5

What is inbreeding?

Answer 5

Breeding selective plants or animals which are related.

Question 6

What is eliminated in inbreeding?

Answer 6

Hetrezygotes.

Question 7

What is a hetrozygote?

Answer 7

An individual with two different alleles for a specific trait.

Question 8

What is a possible affect of inbreeding?

Answer 8

Inbreeding depression.

Question 9

What is inbreeding depression?

Answer 9

An increase in the frequency of individual who are homozygous for recessive deleterious allels. These individuals will do worse at surviving.

Question 10

What can happen as a result of inbreeding depression?

Answer 10

Decline in vigour, size, fertility, and yeild.

Question 11

What is cross breading?

Answer 11

Crossing a cultivar or breed with an individual with a different desired genotype.

Question 12

What is produced when 2 different inbred homozygous cultivar of plant species mate?

Answer 12

Offspring who are uniformly heterozygous.

Question 13

What is hybrid vigour?

Answer 13

When poorer recessive genes are masked by superior dominant ones.

Question 14

What other ways can plants and animals be enhanced?

Answer 14

1. Genetic sequencing

2. Recombinant DNA technology.

Question 15

How can genetic sequencing be used to enhance cultivars and breeds?

Answer 15

Genetic sequencing can be used to identify organisms that posses particular alleles for a desired characteristics. These can then be selected for use in a breeding program.

Question 16

What is genetic transformation?

Answer 16

When breeding programs use crops that have been genetically modified by recombinant DNA technology.

Question 17

What are some examples of genetic transformation being used?

Answer 17

Bt toxin and Glyphosphate resistance gene.

Question 18

How does the Bt toxin gene benefit the plant?

Answer 18

The Bt gene is found in soil bacterium which makes proteins that are toxic to certain plant pests.
This gene is inserted into the crops which makes them resistant to pests.
This means that crops do not need to be sprayed with insecticide.

Question 19

How does the glyphosate resistant gene benefit plants?

Answer 19

Glyphosphate is a weed killer but some plants are naturally resistant to it.
Scientists can transfer the responsible gene for this immunity into crop plants such as soya bean and maize.
This means that when weed killer is used the crops are not affected.

Question 20

What is a field trial?

Answer 20

Field trials are controlled experiments carried out in a range of environments to compare the performance of different cultivars or treatments.

Question 21

What makes an experiment valid?

Answer 21

All other variables, except the independent variable, are kept the same.

Question 22

What makes an experiment reliable?

Answer 22

Several repeats are completed.

Question 23

What makes an experiment accurate?

Answer 23

The measuring techniques are all completed correctly and precisely.

Question 24

What must be done in an experiment for the elimination of measurement bias?

Answer 24

The experiment set up must be random.

Question 25

What are the small areas of land in field trials called?

Answer 25

Plots.