BRAINCAKENatural selection and genetic modification
Revision notes for Natural selection and genetic modification in Edexcel Combined Science (1SC0). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Charles Darwin's theory of evolution by natural selectionCharles Darwin proposed that species change over long periods of time by natural selection.
- Resistant organisms and antibiotic resistanceBacteria reproduce very quickly, so a population can change in a short time.
- Evidence for human evolution from fossilsFossils of early humans and their relatives show how our ancestors changed over millions of years.
- Evidence for human evolution from stone toolsEarly humans made stone tools, and these give evidence of how their skills developed.
- Three domains and five kingdomsFor a long time scientists classified living things into five kingdoms: animals, plants, fungi, protists and prokaryotes.
- Selective breedingSelective breeding is when humans choose which organisms breed, so that useful characteristics are passed on.
- Describe genetic engineering as a process which involves modifying the genome of an organism to introduce desirable characteristicsThe genome of an organism is all of its genetic material, and the genes in it carry the instructions for its characteristics.
- Describe the main stages of genetic engineering including the use of: a restriction enzymes b ligase c sticky ends d vectorsGenetic engineering follows a series of stages.
- Evaluate the benefits and risks of genetic engineering and selective breeding in modern agriculture and medicine, including practical and ethical implicationsSelective breeding has produced crops and animals with higher yields, more milk or meat, and resistance to disease, and it needs no special equipment.
- Deduce the relative reactivity of some metals, by their reactions with water, acids and salt solutionsThe reactivity of a metal is how readily it reacts.
- Recall that the extraction of metals involves reduction of oresAn ore is a rock that contains enough of a metal compound for it to be worth extracting the metal.
- Explain how a metal’s relative resistance to oxidation is related to its position in the reactivity seriesCorrosion of a metal is oxidation: the metal reacts with oxygen to form a metal oxide, so oxidation is the gain of oxygen.
- Evaluating data from a life cycle assessmentA life cycle assessment (LCA) measures the effect a product has on the environment at every stage of its life.
- Reversible reactionsMany reactions go one way only, but some are reversible.
- Making ammonia and dynamic equilibriumAmmonia, NH3, is made from nitrogen and hydrogen.
- Conditions for the Haber processThe Haber process makes ammonia from nitrogen and hydrogen.
- Predicting changes in the position of equilibriumThe position of equilibrium tells us how much product there is in the mixture.