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B3 Life on Earth - revision

B3 Life on Earth - revision. What makes organisms members of the same species?. If they can mate and produce fertile young. What are the two different causes of variation in living things?. Genes and environment. What is the evidence for evolution?.

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B3 Life on Earth - revision

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  1. B3 Life on Earth - revision

  2. What makes organisms members of the same species? • If they can mate and produce fertile young

  3. What are the two different causes of variation in living things? • Genes and environment

  4. What is the evidence for evolution? • Fossils and the similarities between living things

  5. Describe selective breeding and give an example? • Selecting which pigs (for example) to breed because they produce the right meat

  6. Briefly describe Natural selection • Survival of the fittest (and passing on your genes

  7. Why is the idea of competition important • If animals compete with each other only the most successful will survive to pass on their genes

  8. Why did Darwin’s ideas take time to be accepted • Because people believed that the Bible was factually true

  9. What is a mutation? • A sudden random change in the genes

  10. What were the first living things like? • Very simple – molecules that could copy themselves

  11. What are the advantages and disadvantages of being multicellular? • Different cells do different jobs but they need to be able to communicate

  12. What are the body’s two main communication systems? • Hormones and nervous system

  13. What do we mean when we say humans and chimps have a common ancestor? • Humans have not evolved from chimps but we have both evolved from something else

  14. How long ago were the first hominids and what made them different from other apes? • Between 1.5 and 4 million years ago – it walked upright

  15. how do humans cause the extinction of other organisms? • By destroying or disrupting natural environments or food supplies

  16. C3 Food Matters - revision

  17. Why do plants need Nitrogen in the soil? • To make protein

  18. Why do we need to keep adding fertilizer to our fields? • To replace nitrogen and other minerals needed for growth

  19. What are the two different approaches to modern farming? • Intensive – lots of fertiliser and pesticides • Organic – none of the above

  20. What are pesticides? • Chemicals used to kill animals and diseases that damage the crops

  21. How can we control pests without using chemicals? • Natural predators like ladybirds

  22. What is meant by sustainability? • A process is sustainable if it can continue without harming the earth.

  23. What chemicals are added to foods and what do they do? • Preservatives – stop it going off • Colours – make it look nice • Flavourings – make it taste nice • Emulsifiers & stabilisers – stop it separating

  24. What are the 5 main nutrients and what do they do? • Carbohydrates – for energy • Proteins – for growth and repair • Vitamins & minerals – to keep healthy • Fats – store energy

  25. Why do large molecules like starch need to be digested? • So they can be dissolved and absorbed into the blood

  26. What is a food allergy • When someone has a reaction to a particular food eg peanuts.

  27. What happens to excess amino acids in our bodies? • Broken down into urea

  28. What do the kidneys do? • Urea and excess water is removed and stored in the bladder

  29. What is the difference between the two types of diabetes? • Type 1 In younger people – controlled by insulin • Type 2 In older people – controlled by diet, medicine and sometimes insulin

  30. What is a risk factor for diabetes • Being overweight or obesity

  31. What is the purpose of the FSA and what do they do? • Food standards agency – encourage people to eat healthily by promoting labelling and good practice

  32. P3 Material choices - revision

  33. What do radioactive materials produce and what does this mean? • Produce ionising radiation which can damage living tissues

  34. what are the three types of ionising radiation? • Alpha beta gamma

  35. what are the properties of the 3 types of ionising radiation? • Alpha – low penetration – high ionisation • Gamma – high penetration – low ionisation

  36. what is the difference between irradiation and contamination? • Irradiation – radiation goes through it • Contamination – contains something that is making radiation

  37. what affects the radiation dose that you could receive? • Time, how close you are (proximity) and type of radiation

  38. how does ionising radiation affect living cells? • Breaks molecules like DNA and can lead to cancer

  39. describe the structure of an atom • Small dense nucleus (protons & neutrons) surrounded by cloud of electrons

  40. what are isotopes? • Atoms that have a different number of neutrons than normal – often radioactive

  41. what is meant by half life? • The time taken for the radioactivity to drop to half its value

  42. give some uses of ionising radiation. • Medical imaging, sterilising, treating cancer

  43. what are the three categories of radioactive waste and how are they disposed of? • LLW/ILW/HLW – High/intermediate/low • It is sealed in glass or concrete and buried

  44. what is nuclear fission and what is it used for? • Splitting heavy elements like uranium to release heat energy

  45. what are the stages of electricity production in a power station? • Heat released 2. Water boiled 3. Steam turns turbines 4. Generator turned

  46. What do we mean when a resource is sustainable? • It will never run out and the environment will not be ruined

  47. What is the precautionary principle? • Better safe than sorry

  48. why are nuclear power stations better than coal-fired power stations? • Don’t produce CO2

  49. why are coal-fired power stations better than nuclear power stations? • Don’t produce radioactive waste

  50. What is radon gas and how do we protect ourselves against it? • Produced by radioactive rocks – we should keep our houses well ventilated

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