Manipulation of food species

Monocultures

  • Monoculture: cultivating a single species, often over a large area
    • Can make cultivation easier, as larger machinery can be used
    • Pests and diseases can spread rapidly if they colonise the field

Control of Genetics

  • Control of genetics: to produce organisms with desired traits, and a lack of undesirable traits

Asexual

Plants

  • Produce genetically identical offspring from the parent
  • No seeds involved

Animals

Sexual

Selective Breeding

  • Used to produce offspring with desired characteristics
  • Breeding genetically similar individuals can increase inbreeding

Belgian Blue Cattle

  • Bred to have the highest muscle mass using selective breeding and artificial insemination
  • Took place over a hundred years, only allowing individuals with the highest muscle mass to mate
    • These individuals had a faulty gene, which stops muscle growth from stopping

Romney Sheep

  • Resistance to roundworm

    1. Took those with natural resistance
    2. Checked their faeces to make sure
    3. Breeding selected individuals

  • Males had to be highly sexually active

  • Needed to have high-quality wool and meat

Meidam Pig

  • Larger litter
  • More teats
  • Combination of Meishan (China) and Large White (Yorkshire) breeds, then the result of this combined with the Landrace breed
  • Using artificial insemination

Embryo Transfer

  1. FSH hormone used to stimulate ovulation and the release of many eggs
  2. These eggs are washed out of the uterus and collected
  3. The eggs are fertilised using sperm from male with desirable characteristics (IVF)
  4. Each fertilised embryo implanted into different surrogate female

Artificial Insemination

  • Semen collected from male with desirable characteristics
  • Used to impregnate females

Advantages

  • Many more young can be produced that by natural mating
  • Semen can be frozen and transported to other farms - transport of animals themselves not necessary

Cloning

  • Banned in the UK and EU
  • Legal since 2008 in the USA
  • Precautionary principle: we have laws against things until scientists can prove that it’s safe

Crossbreeding

  • Crossbreeding: producing offspring by mating parents of two different breeds
  • Creates hybrids of different breeds
  • Used to create hybrids with desirable characteristics from different breeds
  • Can create hybrid vigour by reducing the problems caused by homozygous recessive genes
  • F1 hybrid: result of breeding two different breeds
  • Hybrid vigour: the improved or increased function of any biological quality in a hybrid offspring

Genetic engineering

  • Transgenics: the introduction of specific characteristics, from one species to another