Unit 3.2 Flashcards
What is selective breeding
Selected individuals are bred together to produce offspring with desirable features
What is needed to design a plant feild trail
1) selection of treatments
2) number of replicants used
3) randomisation of treatments
What is the rule for the selection of treatments
Only one variable should be altered to ensure a fair comparison can be made
What is the reason for using numbers of replicants in plant feild trails
Minimise experimental error and take account of the variability withing a sample
What is the purpose of the randomisation of treatments in plant field trails
Eliminates bias
What is the negative effect of inbreeding
Loss of heterozygosity
Increases the frequency of individuals who are homozygous for recessive deleterious alleles which results in inbreeding depression
Why are slef pollinating plants not affect by inbreeding?
Recessive deleterious alleles would be removed by natural selection
What is outbreeding
Unrelated members of teh same species breed and promote heterozygosity
How are F1 hybrids made?
A cross between 2 genetically dissimilar parents
Why are F1 hybrids not bread together
F2 generation shows too much variation
How can competition in monocultures be destroyed
Reduced by spreading out crops seeds
What is the negative aspects of weeds?
Cause reduction in crop activity
Act as hosts for pests and diseases
What are the properties of annual weeds?
Life cycle of one year
Grow very quickly
Short life cycle
Produce vast numbers of seeds that last for long periods of time
What are the properties of perennial weeds?
Live for several years
Become dormant in winter
Reproduce asexually
They have storage organs that provide food when conditions are ruff
What are plant diseases caused by
Fungi
Bacteria
What are the non chemical ways crops can be protected
Ploughing
Weeding
Crop rotation
What are selective herbicides
Speeds up the metabolism of broad leafed plants so they use up all of their food resources and die
What are systemic herbicides
Transported thorigh the plants vascular system and has a lethal affect, killing the roots prevents regrowth
What is IPM a combination of chemical biological and cultural methods to improve crop yeild
What are indicators of poor animal welfare
Stereotype
Failure in sexual behaviour or reproduction
Altered activity levels
What is a stereotype
Repetitive behaviours
What is misdirected behaviours
Self mutalation
What are altered activity levels
High level of activity (hysteria)
Apathy which is a low level
What is a failure in sexual reproduction
Rejection of offspring
