B14 Variation + Evolution
- Created by: Lucy Hart
- Created on: 04-02-20 12:44
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- B14 Variation + Evolution
- B14.1 Variation
- genetic (nature) - dimples
- environmental (nurture) - tatoos
- B14.2 Evolution by Natural Selection
- evolve through natural selection
- due to mutation - change in DNA code
- less adapted die
- evolve through natural selection
- B14.3 Selective Breeding
- humans breed plants + animals for desired characteristic
- 1. farmers choose parents with desired characteristic
- 2. best offspring selected + used to breed next generation
- 3. Process continues over many years leading to desired characteristic
- limitations
- little variation
- prone to inherited diseases
- interbreeding - reduction in alleles
- problem if environment changes
- little variation
- B14.4 Genetic Engineering
- modifying the genetic material for desirable characteristic
- 1. enzymes are used to cut out required gene
- 2. inserted into a vector
- 3. insert the gene into the cell
- 2. inserted into a vector
- early stage so develop new characteristic
- B14.7 Ethics of Genetic Technologies
- Advantages
- cure inherited human disorders
- agriculture
- improved rates of growth of plants + animals
- increased food value due to bigger yields
- plants make their own pesticides
- Concerns
- concerned about effect on human health
- infertility genes spreading into wild populations
- manipulate genes of future children
- Advantages
- B14.5 Cloning
- clone - individual that has been produced asexually + is genetically identical to parent
- cloning plants
- taking cuttings
- cut at angle, place in soil with auxins
- tissue culture
- tissue sample scraped from parent plant, put in agar plate with auxins
- taking cuttings
- cloning animals
- 1. give fertility hormones to top quality cow so produce many eggs
- 2. fertilise with sperm from good quality bull
- 3. embryos washed out of uterus + cells grow in lab
- transplanted into host mother
- 3. embryos washed out of uterus + cells grow in lab
- 2. fertilise with sperm from good quality bull
- 1. give fertility hormones to top quality cow so produce many eggs
- benefit - save from extniction
- risk - reduces variety
- B14.6 Adult Cell Cloning
- 1. nucleus removed from egg cell (B)
- 2. nucleus taken from adult body cell (A)
- 3. electric shock to start dividing
- 4. ball of cells inserted into womb (C)
- 5. lamb born clone of (A)
- 4. ball of cells inserted into womb (C)
- 3. electric shock to start dividing
- 2. nucleus taken from adult body cell (A)
- 1. nucleus removed from egg cell (B)
- B14.1 Variation
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