U3 KA2 Flashcards
1
Q
What 4 characteristics can animals and crops be selectively bred to have?
A
- improved nutritional values.
- disease and pest resistance.
- an ability to survive harsh conditions.
- higher food yields.
2
Q
What is the purpose of carrying out Field Trials? (2)
A
- to monitor GM crop performance.
- to access and compare the performance of cultivars in different environments.
3
Q
What three procedures must take place when carrying out Field Trials?
A
- Selection of Treatments.
- Randomisation of Treatments.
- Number of Replicates.
4
Q
Why does a Selection of Treatments take place?
A
- to ensure valid comparisons can be made.
5
Q
Why does a Randomisation of Treatments take place?
A
- to eliminate bias when measuring treatment effects.
6
Q
Why is the Number of Replicates important?
A
- to take into account variability within the sample.
7
Q
What is Inbreeding?
A
- when selected plants or animals are bred with closely related relatives.
8
Q
Why is inbreeding carried out?
A
- it is done over multiple generations until a desired characteristic breeds true, and until heterozygous genotypes are bred out.
9
Q
What can inbreeding result in?
A
- an offspring becoming homozygous with recessive deleterious alleles, creating negative phenotypes.
10
Q
What is the result of inbreeding depression?
A
- an offspring with reduced size, vigour, fertility and yield.
11
Q
Why is cross breeding used?
A
- to prevent inbreeding depression, and introduce new alleles to plant or animal lives.
12
Q
How do F1 hybrids compare to their parents?
A
- they display hybrid vigour and desirable traits from both parents.
- they are often larger.
13
Q
Why are F1 hybrids not often bred together?
A
- F2 hybrids show too much variation.
14
Q
What process is used to maintain a new breed?
A
- back crossing and selection.
15
Q
Why has milk yield improved?
A
- due to an improvement in cattle diet, now containing required nutrients.
