Unit 3 Key Area 2 Flashcards
Why might a plant or animal breeder breed particular individuals?
To help improve certain characteristics, or to help support sustainable food production
What might be some of the characteristics that breeders of plants or animals select for?
- Increased nutritional value
- Increased food yields
- Increased resistance to pests or disease
- the ability to thrive in particular environmental conditions
Suggest some of the reasons why a field trial might be carried out?
Field trials are carried out to
- evaluate the performance of different cultivars
- evaluate different GM crops
What are the factors that must be taken into account when designing field trials?
- Selection of treatments
- number of replicates
- randomisation of treatments
Why must selection of treatments be taken into account when designing a field trial?
Selection of treatment ensures valid results are drawn from the field trial
Why must number of replicates be taken into account when designing a field trial?
To take into account the variability of results within the sample
Why must randomisation of treatments be carried out when designing a field trial?
To eliminate bias when measuring treatment effects
Describe the process of inbreeding?
selected individuals of related plants or animals are bred together for several generations until the population breeds true to the desired type. Due to the elimination of heterozygotes.
What is meant by inbreeding depression?
Inbreeding depression is caused by excessive inbreeding where there is an increase in the frequency of individuals that are homozygous for a deleterious alleles. These individuals will not do well at surviving to reproduce due to the expressed deleterious characteristics.
How can new alleles be introduced into plant and animal lines?
by crossing a cultivar with an individual of a different desired genotype (in plants)
by crossing a breed with an individual of a different desired genotype (in animals)
This practice is called crossbreeding
Why are the F1 generations in naturally inbreeding plants or animals not bred together?
As the resulting F2 variation will display too much variation of the desired characteristic.
What are some of the ways of genetically modifying plants to have increased pest resistance and herbicide tolerance?
- The BT toxin gene when inserted into plants causes increased pest resistance
- glyphosate gene gives the plant an increased tolerance for herbicides.
