3.1 classification

• order of classification system

  • kingdon
  • phylum
  • class
  • order
  • family
  • genus
  • species
• why is it hard to assign organisms to one species?

  • species change genetically overtime
  • how 'similar' should they be to be classed as one
• what is a species?

  organism that can breed to produce fertile offspring

  and have similar characteristics
• limitations of definition of species

  • doesn't account for hybrids - have variations with fertile offsprings
  • difference in species aren't obvious
  • how much variation is tolerated
• morphology definition - do they same similar characteristics

  ecological definition - do they share same ecological niche

  reproductive definition - do they produce fertile offspring

  evolutionary definition - do they share common ancestor
• what is molecular phylogeny?

  • molecular similarities in DNA base sequence
  • showing evolutionary relationships
• how do you evaluate scientific data?

  • peer review - asses validity
  • publish in scientific journal
  • scientific conference
• what is the 5 kingdom model?

  • prokaryotae
  • protoctista
  • fungi
  • plantae
  • animalia
• limitation of 5 kingdom model

  • based on structural differences
• what is the 3 domain model, advantage?

  • archaea
  • bacteria
  • eukarya

  based on molecular similarities
• how do you analyse evolutionary relationships

  via...

  • gel electrophoresis
  • dna sequencing
  • bioinformatics
• how does gel electrophoresis work?

  • dna sample amplified by PCR
  • restriction enzyme breaks DNA into fragments
  • stained with dye
  • potential difference used
  • DNA shows up as bands
  • number of bands links to similarities - therefore shows relationships
• how do bioinformatics and dna sequencing show relationships?

  • help compare genomes
  • can look at mutations and genetic differences