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  1. What was the earth like 4.8 billion years ago?
    The atmosphere was 98% CO2 and the air temperature was a lot higher than now
  2. What was the earth like 3.5billion years ago?
    Simple celled organisms with no nucleus formed
  3. What was the earth like 3 billion years ago?
    Algae photosynthesised changing the atmosphere
  4. What was the earth like 2.8 billion years ago?
    The earth's crust hardened and the oldest rocks were formed.
  5. What was the earth like 65 million years ago?
    Dinosaurs became extinct this is thought to be because of an asteroid hit the earth
  6. What was the earth like 1.5 billion years ago?
    Eukaryotes were formed (more complex organisms)
  7. What was the earth like 500 million years ago?
    The ozone layer formed, fish and plants appeared
  8. What was the earth like 300 million years ago?
    Reptiles formed
  9. What was the earth like 200 million years ago?
    Mammals appeared
  10. What was the earth like 4 million years ago?
    Two legged mammals appeared
  11. What was the earth like 60,000 years ago?
    The first writing was found
  12. What was the earth like 10,000 years ago?
    Homosaipans  learnt to use fire and for casting copper and making pottery
  13. What are similarities of meiosis and mitosis?
    They both go through interphase where chromosomes duplicate

    Both processes that cells can divide

    Spindle fibres are used

    Line up along centre

    Main phases

    At some point two nuclei are formed
  14. What are differences between meiosis and mitosis?
    In mitosis the gens don't mix and they do in meiosis

    • In mitosis there are two daughter cells are created but in
    • meiosis there are four

    • Mitosis diploid number of chromosome and meiosis there is
    • haploid

    • Mitosis happens in all organisms and meiosis happens in
    • animals
  15. What is a stem cell?
    An undifferentiated cell of an embryo.
  16. What can stem cells become?
  17. Any type of cell in the human body.
  18. What is different about cancerous stem cells?
    They lack control to stop dividing.
  19. Name two things stem cells 
    are used for.
    Parkinson's disease

    Alzheimer's disease

    heart disease





    spinal chord damage
  20. Name fears on stem therapy.
    • It could unwillingly pass viruses and other diseases causing
    • agents to people who receive cell treatment
  21. Where else can stem cells come from?
    Adults without 'hurting' but not as good as embryos
  22. What can happen if you receive stem cell treatment?
    • Your body's immune system my reject it as they recognised it
    • as foreign
  23. What does stem cells research hold the key to?
    To reversing the effects of aging and prolonging our lives
  24. What do some people believe about stem cell research?
    It is unethical because they believe that they are fully developed human corpse
  25. What is a phenotype?
    • Characteristics and it is determined by the pair of alleles
    • you have (genotype)
  26. Which is dominant? Bb
  27. Which is recessive? Bb
Card Set:
2014-05-04 10:35:28
Science Biology
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