classification and evolution

• Taxonomy


  The grouping of organisms according to their characteristics
• There are eight taxonomic groups used to classify organisms
• Domain


  The broadest taxonomic category
• Species


  The most specific taxonomic category
• "Dear King Phillip Came Over for Good Soup" or "Delicious King Prawn Curry Over Fatty Greasy Sausages" is a mnemonic to remember the order of the taxonomic groups
• Five kingdoms


  • Animals
  • Plants
  • Fungi
  • Protoctists
  • Bacteria
• Animal kingdom


  • Eukaryotic multicellular organisms, no cell walls, store carbohydrates as glycogen, cannot photosynthesize (heterotrophic)
• Plant kingdom


  • Eukaryotic multicellular organisms, cell walls made of cellulose, store carbohydrates as starch, obtain organic molecules by photosynthesis (autotrophic)
• Fungi kingdom


  • Eukaryotic organisms, can be unicellular (e.g. yeast) or multicellular (e.g. mushrooms), cell walls made of chitin, store carbohydrates as glycogen, obtain food by saprotrophic nutrition
• Protoctist kingdom


  • Eukaryotic organisms, usually unicellular, some protoctists have a cell wall, some have chloroplasts
• Bacteria kingdom


  • Prokaryotic unicellular organisms, no nucleus, very small
• Binomial system


  A two-name system for naming organisms using the genus name and the species name
• The scientific name for humans is Homo sapiens
• Molecular phylogeny


  The study of molecules (such as DNA, RNA, or amino acids) within an organism to determine evolutionary relationships
• Comparing DNA sequences can determine how closely related two organisms are
• Phylogenetic tree


  Represents evolutionary relationships among species, showing common ancestors and divergence points
• Three types of evidence used for classification other than molecular evidence

  • Embryological evidence
  • Behavioural evidence
  • Anatomical evidence
• Three-domain system


  A classification system that groups life into three domains: Bacteria, Archaea, and Eukarya
• Variation within a population is caused by genetic causes (alleles inherited), environmental causes, and a combination of both
• Intraspecific variation


  Variation within a species
• Interspecific variation


  Variation between different species
• Continuous variation


  Variation where individuals in a population vary within a range, typically controlled by many genes (polygenic)
• Discontinuous variation


  Variation where phenotypes can be grouped into distinct categories, typically controlled by a single gene (monogenic)
• High genetic diversity


  Leads to high phenotypic variation due to a greater number of possible characteristics
• To ensure a random sample in a study of variation, divide the habitat into a grid and use a random number generator to select coordinates
• Standard deviation


  A measure of the spread of values about the mean
• Error bars


  Represent standard deviation, indicating the variability of the data
• Behavioural adaptations


  Ways an organism acts that increase its chances of survival, like fish swimming in schools or birds migrating
• Physiological adaptations


  Processes within an organism's body that increase its chances of survival, like a sloth's low metabolism
• Anatomical adaptations


  Structural features of an organism that increase its chances of survival, like polar bears' camouflage
• Convergent evolution


  When organisms in different taxonomic groups develop similar characteristics due to similar environments
• Natural selection


  The process by which species evolve due to individuals with advantageous traits surviving and reproducing more successfully
• Gene mutations cause new alleles to appear in a population
• Frequency of advantageous alleles

  Increases as individuals with these alleles are more likely to survive and reproduce
• Evidence that supports Darwin's theory of evolution

  • Fossils showing gradual changes in species over time
• More closely related species have more similar DNA, supporting evolution
• How organisms evolve resistance to pesticides

  Through natural selection, where a mutation gives an insect an allele for pesticide resistance
• Pesticide resistance is a serious problem as it makes pest control difficult, can lead to significant crop loss, and may spread diseases
• Five kingdoms of life

  • Animals
  • Plants
  • Fungi
  • Protoctists
  • Bacteria
• The scientific name for a chimpanzee is Pan troglodytes