Evolution

• Resistant bacteria


  Bacteria that are resistant to antibiotics
• Bacteria can evolve rapidly because they reproduce very quickly
• This has led to many strains of bacteria developing antibiotic resistance, such as MRSA
• The development of antibiotic resistance in bacteria is evidence for the theory of evolution by natural selection
• Emergence of antibiotic resistance

  The development of new strains of antibiotic-resistant bacteria
• The development of new antibiotics is expensive and slow, so it cannot keep up with the emergence of new strains of antibiotic-resistant bacteria
• To reduce the rise of antibiotic-resistant strains


  1. Doctors should only prescribe antibiotics for serious bacterial infections

  2. Patients should complete their courses of antibiotics so all bacteria are killed and none survive to form resistant strains

  3. The use of antibiotics in farming and agriculture should be restricted
• Classification of living organisms

  A system developed by Carl Linnaeus to classify living things into groups, based on their structure and characteristics
• Evolutionary trees


  Use current classification data for living organisms and fossil data for extinct organisms to show how scientists believe organisms are related
• New models of classification were proposed as the understanding of biochemical processes developed and improvements in microscopes led to discoveries of internal structures
• Three-domain system


  Developed by Carl Woese, dividing organisms into Archaea (primitive bacteria usually living in extreme environments), Bacteria (true bacteria), and Eukaryota (including protists, fungi, plants, and animals)
• Organisms are named by the binomial system of genus and species
• Remember: Lots of students get the key words in this topic mixed up - evolution and natural selection are linked but are not the same, so learn the differences carefully