Biology Topic 3

• 1. Define classification

  The process of naming and organizing organisms into groups based on their characteristics.
• 2. Name the Eight groups an organisms can be classified into

  1. Domain
  2. Kingdom
  3. Phylum
  4. Class
  5. Order
  6. Family
  7. Genus
  8. Species
• Define species

  A group of species that can interbreed to produce fertile offspring
• Give a limitation of this definition of species

  Does not account for species that reproduce asexually
• Why can it be difficult to assign organisms to one species?

  Species often change both morphologically and genetically over time
• How can we analyze evolutionary relationships genetically?

  1. Gel electrophoresis
  2. DNA Sequencing
  3. Bioinformatics
• How does gel electrophoresis work?

  1. Make wells in arose jelly
  2. Put DNA fragments cut with restriction endonuclease enzymes in them
  3. Dye the DNA with something that fluoresces
  4. Turn on a current
  5. DNA is negatively charged so it moves towards the anode
  6. Turn the current off
  7. Turn the UV light on
  8. Different bands represent different amino acids and can be compared to known fragments
• How does DNA sequencing work?

  • DNA is broken down to small fragments, terminated at different lengths by fluorescently marked nucleotides, then duplicated using PCR.
  • The fragments undergo gel electrophoresis, with the smallest fragments travelling furthest, meaning we can read the base sequence of the fragment according to distance travelled.
• What is Bioinformatics?

  The use of technology and software to anaylse large amounts of biological data.

  Can compare entire genomes and look for where mutations have caused divergence in the phylogenetic tree .
• How does the scientific community evaluate data ?

  Papers sent out to other experts for peer review to check for validity .If the data and the conclusion seem reasonable, results are published in scientific journals .May also be presented in conferences.
• Why has the Five -Kingdom model of classification come under scrutiny ?

  • Relies heavily on physical observation.
  • Since the introduction of DNA sequencing ,new models have been developed.
• Why is the Three-Domain model of classification more accepted by the scientific community ?

  • Takes into account research of a particular ribosomal unit.
  • More accurately represents evolutionary relationships than Five- Kingdom,
• Why does natural selection occur?

  1. Predation
  2. Disease
  3. Competition
• Explain how natural selection results in development of new characteristics ?

  • Random mutation results in new alleles
  • Some alleles gives the possessor an advantage over the result of the species, making them more likely to survive nd reproduce
  • There offspring receives new alleles and frequently continues to increase over generations
• What are the three types of adaptations ?

  1. Anatomical - Changes to the body structure
  2. Physiological - Changes to the body processes
  3. Behavioral - Changes to the actions