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topic 6- inheritance, variation and evolution (variation (different genes…

- - - - = when a new base is inserted into dna base sequence where it shouldn't be
      - an insertion changes the way groups of 3 bases(which code for a particular amino acid) are read which can change what amino acids code for
      - insertions can change more than one amino acid as have knock on effect on bases further on in sequence
    - - =when a random base is deleted from dna base sequence
      - they change the way that the base sequence (3 bases) is read and have knock on effects further on in sequence
    - - = when a random base in the dna base sequence is changed to a different base
- - - - genetic variation
      - environmental variation
- - - - environment changes too quickly
      - a new predator kills them all
      - a new disease kills them all
      - they cant compete with another new species for food
      - a catastrophic event happens that kills them all
- - - - to develop more useful features
      - to make an organism more attractive
    - - 1) from existing stock select organisms that have desired charcteristics
      - 2) breed them with eachother
      - 3) select the best of the offspring and breed them together
      - 4) continue process over several generations and the desirable trait gets stronger- eventually all offspring will have that characteristic
- - - - where a few plant cells are put in a growth medium with hormones
      - they grown into new plants (clones of the parent)
      - they can be grown quickly in very little space
    - - gardeners can take cuttings from good parent plants and then plant them to produce genetically identical copies of the parent plant
      - these plants can be produced quickly and cheaply
  - - - it can reduce the gene pool which could result in a species being wiped out if a disease was introduced
      - cloned animals could be less healthy than normal animals
      - concerns that humans could be cloned in the future
    - - cloning could be used to preserve an endangered species
      - however study of animal clones could improve understanding of the embryo and aging related disorders
- - - - things like teeth, bones don't decay easily so last a long time when buried
      - they're eventually replaced by minerals as they decay forming rock like substances shaped like the original part
      - the surrounding sediments also turn to rock but the fossil stays distinct inside the rock and eventually someone digs it up
    - - sometimes fossils are formed when an organism is buried in a soft material like clay. the clay later hardens around it and the organism decays leaving a cast of its self
    - - in amber and tar pits there is no oxygen or moisture so decay organisms can't survive
      - in glaciers its too cold for decay microbes to work
      - peat bogs are too acid for decay microbes
- - - - over use/ prescription of antibiotics
      - people not finishing their courses