Evidence for evolution

• Bacteria evolve quickly as they reproduce at a fast rate. (Double every 20 minutes).
• Mutations cause new strains of bacteria.
• Antibiotic resistance is when certain bacteria will no longer be killed by the antibiotic and will become resistant.
• The 4 main stages in the development of antibiotic resistance are:


  -Random mutations occur in the genes of individual bacterial cells.

  -Some mutations protect the bacterial cell from the effects of the antibiotic.

  -Bacteria without the mutation will die or cannot reproduce when the antibiotic is present.

  -Resistant bacteria can reproduce with less competition from normal bacteria strains.
• MRSA is so dangerous as it is resistant to most antibiotics..
• The number of MRSA strains increase.
• This has resulted in more infections that are difficult to control.
• Three measures that can prevent the development of antibiotic resistance:

  -complete full course of antibiotics.

  -Only take them when needed.

  -Stop using them in farming.
• The first antibiotic was created in 1928 by Alexander Fleming.(Penicillin)
• It is derived from penicillium mold.
• Most antibiotics were discovered in the 1950s and 60s.
• The need for new antibiotics is on the rise as more people are becoming resistant to the ones we already have.
• Two main problems with making new antibiotics is that they are costly and take time to develop.
• Wafarin is the active ingredient in rat poison.
• Random mutations in the genomes of rats have caused some of them to become resistant to them.
• The number of resistant rats will increase whereas the number of non-resistant rats will decrease.
• This is known as survival of the fittest.
• Warfarin no longer works as more and more rats are becoming resistant to it.
• Extinction is when a species dies out as they have not adapted well to their environment.
• Extinction has a role in evolution as some species disappear, whilst others survive and continue to evolve.
• 6 factors as to why some species go extinct:


  -new diseases.

  -competition.

  -new predators.

  -changes to environment.

  -a catastrophic event.(asteroid + volcano eruption)
• Fossils show us that some species have gone extinct over time.(dinosaurs)
• Extinction is still happening today.
• Extinction occurs due to human activity.
• The dodo became extinct as humans went to the island where the dodos were and they ate them. Dodos were easy to catch as prey as they could not fly.