variation and evolution Flashcards
what factors make us differnet
-nature/ inherited genes
- nurture eg scars
- combination
whats natural selection
orgaisms with an advantage in competition are more likely to survive and breed and so pass down their desireable traits
why do species have genetic variation
- mutation in genes
- difference in genes via meisois and reproduction
how does surivival of the fittest work
- a species has wide genetic variation and phenotype
- individuals w more suited characteristcs will survive and breed
-alleles that help them surivve will be passed down
whats selective breeding
choosing an optimal variation of species to breed to get offspring w the desired traits
how does selective breeding work
- select ideal charcteristics in the animal/plants from a population and breed
- select the ones from the offspring who recieved the desired characteristics
- breed the offspring w the ideal characteristics and repeat
things that can be selected through selective breeding
-disaease reseitent crops and plants
- farm animals w more meaet or milk
- gentle natured animals
- particular bright or large flowers
neg consequences of selective breeding
- reduces alleles/genes so decreases variation
- lack of variation can result in populatio death
- inbreeding- can result i lack of variation, high risk of disaesae and inherited defects
what is genetic enjineering
- changing genetic material of an organism giving it more desireable traits
how does genetic enjineering work
- enzymes isolate/cut out the required gene
- more enzymes insert this gene into a vector
- vector carries gene into required cells
- organism will then grow w the cells carrying this characteristic as those cells will divide by mitosis
when is genetic engineering
early stage of developement eg as a foetus
what are GM crops
genetically modified crops
examples of gm crops
- resistent to insect attacks
- increased yields
- more resistent to herbidices
- increases nutritional value
- soy beans have less fatty acids
- resistnet to diseases
benefits of genetic enjineering for humans
- bacteria and fungi can make hromones and insulin
- mice can mimic diseases
pros of genetic enjineering in agriculture
- gowth rates
- yields/ food value of crops
- crops can grow i all conditions
- own pesticiode or resistnet to herbicide
concerns of genetic enjineering
- insects can become pestcide resistent
- fear of eatig gm food/ food w extra genes
- gm plant genes could spread ad they are infertile
- fears of human enjieering ad ‘designer babies’
how can fossils be formed
- when an animal doesnt decay because of no oxyge or bacteria or low temps which preserves the animal exacted eg in ice or peat
- when part of the animal is replaced by minerals and becomes part of a rock,
- when an impession is left in mud which is filled in and fossilised
- preserved traces eg droppings or footprints
why is the fossil record not complete
- many were soft bodies so cant be mineralised or leave an impression
- early fossils wouldve been destroyed by geological activity eg erosion and volacnoes
- right conditions for fossilisation is rare
- many are still to be found
whats extinction
permenent loss of all members of a species
what cab cause extiction through living organisms
- new predators/evolved predators
-new disease - new mutations of a competing species means competition is too powerful
enviromental factors that cause extinction
- change in climate/temperature
- sudden catastrophic event
evidence for astroid
- huge crater
- crater debris
- mineral formed when rocks are hit w force
how does antibiotic resistent bacteria grow
- natural mutation in a bacteria
- they will then survive and reproduce
- the strain will spread rapidly
how to prevent antibiotic resistence
- dont overuse antibiotics so other bacterias are still around
- patients finish full course of medecine so all of those bacterias are killed
- restrict animal antibiotics to stop spread of resistence
