B15 Genetics + Evolution
- Created by: Lucy Hart
- Created on: 16-02-20 12:15
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- B15 Genetics + Evolution
- 15.1 History of Genetics
- mid 19th - Mendel cross bred peas + found characteristicwere inherited in clear + predictable patterns, some dominant
- inheritance of each characeristic is detemined by 'units' that are passed on by descendants
- early 20th - observed chromosomes + Mendel's 'units' behaved in a similar way. Units discovered as genes
- inheritance of each characeristic is detemined by 'units' that are passed on by descendants
- gene theory
- genes code for different proteins
- mid 19th - Mendel cross bred peas + found characteristicwere inherited in clear + predictable patterns, some dominant
- 15.2 Theories of Evolution
- Lamarck - organisms linked by 'fountain of life'
- 'use it or lose it', if animal uses feature it would grow + develop + passed on
- unpopular because no evidence, didn't like being descended from worms
- 'use it or lose it', if animal uses feature it would grow + develop + passed on
- Darwin's theory - natural selection
- individual organisms show range of variation
- reproduction gives more offspring than environment can support - fittest more likely to survive
- pass on to next generation
- Lamarck - organisms linked by 'fountain of life'
- 15.3 Accepting Darwin's ideas
- built up evidence with beaks of finches, pigeons + barnacles+ published
- objection
- God
- insufficient evidence
- genetics not understood
- 15.4 Evolution + Speciation
- Wallace - theory of speciation
- raced with Darwin
- no longer interbreed to produce fertile offspring
- new species
- isolation
- genetic variation
- natural selection
- speciation
- Wallace - theory of speciation
- 15.5 Evidence for Evolution
- incomplete fossil record
- still not found
- right conditions for fossils rare
- destroyed by geological activity
- fossilisation
- doesn't decay because no oxygen present so almost intact
- rare but can extract DNA
- harder parts of animal decay + become part of rock replaced by minerals, impression made in mud + fossilised
- fossil - remains of organism from millions of years ago preserved in rock
- doesn't decay because no oxygen present so almost intact
- incomplete fossil record
- 15.6 Fossils + Extinction
- extinction - permanent loss of specie
- new predators
- new diseases
- new mutations
- learn from fossils how much or little a specie has changed
- extinction - permanent loss of specie
- 15.7 More about extinction
- asteroid impact
- evidence - KP boundary - unusually sharp lines + large amount of iridium
- effect - destroyed all wildlife caused by sunlight to be blocked stopping photosynthesis + dispersed aerosol in atmosphere
- evidence - KP boundary - unusually sharp lines + large amount of iridium
- volcanic activity
- evidence - KP boundary + Deccan traps in India
- effect - huge fires, earthquakes, landslides, tsunamis + dark
- asteroid impact
- 15.8 Antibiotic Resistant Bacteria
- becomes resistant by...
- antibiotic kills most dangerous bacteria so less competition
- mutation + reproduce rapidly
- prevention
- finish course
- not to overuse antibiotics
- restrict agricultural use
- medicines for future
- fish slime + crocodile blood
- MRSA
- in hospitals
- stop spread by...
- high standards of hygiene (hand washing)
- only used when really needed
- isolation of patients
- becomes resistant by...
- 15.9-10 Classification
- Linnaeus - two kingdoms
- kingdom, phylum, class, order, family, genus, species
- Woese - new system, 3 domains 6 kingdoms
- archea- extremeophile live in extreme conditions
- arachaebacteria
- bacteria - new bacteria photosynthesis
- eubacteria
- eukaryota - contain a nucleus
- protist
- fungi
- animal
- plant
- archea- extremeophile live in extreme conditions
- Linnaeus - two kingdoms
- 15.1 History of Genetics
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