Variation and Evolution Flashcards
What does selective breeding actually do?
Gives plants and animals strange combinations of genes that would probably never have occurred naturally
What is selective breeding?
Process where humans breed plants and animals for desired characteristics
What are some desired characteristics given from selective breeding?
Disease resistant crops
Animals that produce more milk or meat
Domestic dogs and farm animals with gentle nature
Large, unusual, brightly coloured, heavy scented flowers
Limitations of selective breedings
- Reduces variation
- If there is a climate change or new disease emerging = lack of variation can mean that none of the animals or plants in the population can cope with this change -> population dies out
- Inbreeding = very little variation, prone to disease or inherited defects, problems giving birth, breathing problems
Process of genetic engineering
1) Enzymes isolate and cut out required gene from an organism
2) Gene inserted into vector using more enzymes
3) Vector is used to insert gene into required cell
4) Genes are transferred to cells in early stage of development
5) As the organism grows it develops new characteristics from the other organism
Transferring genes to animal and plant cells
Genetically engineered bacteria and fungi, can make huge quantities of protein from other organisms
Genes can be transferred to animal and plant cells as well as bacteria and fungi
Genetically modified crops
Increased yields Make their own pesticide More resistant to herbicides Increased size of fruit Increase nutritional value More resistant to diseases
How to clone a plant?
1) take explants from the parent plant
2) transfer to plates containing sterile agar jelly
3) add plant hormones to stimulate the plant cells to divide
4) cells grow rapidly into small masses of plant tissue
5) add more plant hormones to stimulate the growth of roots and stems
6) transfer the plantlets into potting trays, where they develop into plants
Adult cell cloning
1) remove diploid nucleus from body of cell
2) enucleation (remove nucleus from egg cell)
3) insert diploid nucleus into enucleated egg cell
4) stimulate diploid nucleus to divide by mitosis using electric shocks
Cloning cows
1) give fertility hormones to cow
2) fertilise eggs she produces using sperm (done inside the cow)
3) embryos produced and washing out uterus
Benefits and risks of adult cell cloning
+ useful proteins in milk = medically useful
+ produce large numbers
+ save animals from extinction
+ help infertile couples
- process can be abused (want to clone theirselves)
- reduces variety
Benefits or genetic engineering
Improved growth rates Increased food value of crops Bigger yields Grow in any conditions Drought resistant Make their own pesticide or resistant to herbicides farmers use to control weeds High nutritional value Only way of solving worlds expanding population and cope with global warming
Risks of genetic engineering
Don’t know long term effects
Don’t know effect on health = body should be able to deal with extra genes, enzymes can break them down
Infertile = can cause problems in environment if they spread to wildlife
Fears about human engineering = people want certain characteristics in their children
