B14: Variation/Evolution Flashcards
what does the phenotype of an organism depend on?
GENOTYPE: - genes inherited /passed from parents
- genetic variation unless twins
ENVIRONMENT: - conditions organism grows and develops affects appearance
define
evolution
change in inherited characteristics of a populaton over time through natural selection which may form a new species
what is the THEORY OF EVOLUTION?
All species have evolved from simple life forms that first developed 3 bill yr ago
process of natural selection?
- Mutation occurs –> variation
- if mutation helps survival , organism will survive to breed
- mutation passed to offspring
- over generations, mutation will become more common in population
what is speciation?
one population of species beocme so different that they can no longer produce fertile offspring - new species
what is selective breeding?
when humans choose whihc organisms to breed in order to produce offspirng with desirable characteristics
process of selective breeding?
- parenst with desirable charateristcis bred tgt
- offspring wth these characteristics are bred
- repeat
problems with selective breeding?
INBREEDING –> breeding with similar characteristics mean its likely they are related closely - REDUCED GENE POOL (as no. different alleles reduce)
- means less genetic variation /can be affected by disease
- can also mean more chance of geentic defects
what is genetic engineering?
modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic
process of genetic engineering of bacteria to produce insulin?
- human insulin genes from chromosomes are ‘cut out’ using RESTRICTION ENZYMES leaving stickey ends
- a virus or bacterial plasmid is cut using same RESTRICTION ENYZYME to also create sticky ends
- loop/gene sticky end are joined together by DNA ligase enzymes
- genetically engineered (recombinant) plasmid is inserted into a bacterial cell
- when bacteria reproduce, plasmids are copied as well / spread (the will all express human insulin gene)
why are plants, bacteria and crop genetically modified?
PLANTS : for disease resistance/larger fruits
BACTERIA: produce useful substacnes fro humans (human insulin)
CROPS: - resistance to insects/herbicides –> high yield
how is genetic modification used in medecine ?
- to cure inherited disorders
called GENE THERAPY - involves transfering normal genes into patients so correct proteins are produced
benefits of genetic engineering?
- useful in medecine to mass produce hormones
- improves yields in agriculture (improves growth rates/ allows plants to grown in different environs/can make own pestcides)
- crops with extra vitamins can be produced in areas, where it is difficult
- more yields –> solve world hunger
risk of genetic engineering?
- GM crops can effect plants therefore insects : - GM crops are infertile , so these genes can spread to plants, leading to infertility in other species
- dont undertant effect of GM crops on human health
- can lead to rise in designer babies
methods of plant cloning?
tissue culture: plant cells are taken and placed in growth medium with nutrients/hormones(auxin)
- grow into new plants that are clones (genetically identcial to parent)
cuttings: taken from plant with desirbale feature , and planted
- produce clones
