natural selection

• natural selection is the process by which organisms better adapted to their environment are more likely to survive and reproduce
• in nature there is competition between members of the same species for limited resources such as food, water and space
• individuals with advantageous traits pass on these genes to offspring through sexual reproduction
• a population is all members of one species living together at the same time
• the individuals that have characteristics that make them best suited to compete will be most successful at surviving and reproducing
• the fittest individuals have characteristics that enable them to survive and reproduce, they pass on these advantageous traits to offspring
• Antibiotics are specifically designed to destroy prokaryote cells, which in your body will be bacteria, instead of your own cells which are eukaryote cells
• Antibiotic resistance can happen in bacteria
• Natural selection

  A process that usually takes a very long time to see
• In a dark habitat with predators

  Lighter frogs are much easier to see than darker frogs
• Fitness

  Determined by how many offspring an organism has
• Darker frogs pass down their DNA to their offspring so that the new baby frogs will have DNA from their parents
• Evolution is change over time and could take place because natural selection has occurred
• Natural selection is a mechanism of evolution
• Variation or mutations are random and not something an organism can "will" itself to have
• Mutations and variation could be negative, positive, or have no effect on an organism's fitness
• Negative ions and mutations

  Could be negative and negatively affect the organism’s fitness, meaning no babies
• Negative effect on fitness

  That trait will not be passed down
• Positive effect on fitness


  Frog may have more babies than average because the trait is helping them survive and reproduce
• Advantageous trait

  Will be more frequent in the population over time
• Natural selection in bacteria from antibiotics

  Environment is being altered when antibiotics are taken
• Bacteria with traits to survive antibiotics

  Have higher fitness and can reproduce, passing on their DNA
• Bacteria without traits to survive antibiotics

  Do not have much fitness as they are dying
• Resistant bacteria


  Are the survivors after selection has taken place
• Resistant bacteria reproducing

  Their offspring can inherit the gene that allows them to be resistant to that specific type of antibiotic
• Bacteria transferring resistant genes


  Can share that resistant gene with other bacteria
• Challenge in hospitals

  Treating multiple patients with bacterial infections in a closed environment
• Hygiene practices for healthcare workers

  Must be good to prevent the spread of resistant bacterial infections
• Scientists developing new antibiotics


  To stay one step ahead of bacteria
• Bacterial strains with resistance to antibiotics


  Making it very difficult to treat
• Importance of taking antibiotics only for bacterial infections

  Antibiotics don't work against viruses