Classification and Evolution

• How the domain system of classification was developed
• Five kingdoms and three domains

  • Kingdoms= Prokaryote, Protoctista, Fungi, Plantae, Animalia
  • Domains= Bacteria, Archaea, Eukaryota
• Components of a binomial name

  • Generic name= the genus the organism belongs to
  • Specific name= the species the organism belongs to
• Advantage of the binomial naming system
• Classification is simply sorting organisms
• Groups in the classification hierarchy

  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
• By analysing molecular differences between organisms to determine their evolutionary relationships (phylogeny)
• How organisms are classified into a kingdom
• Groups an organism can be classified into

  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
• It is universal; an organism’s binomial name is the same everywhere in the world
• Difference between classification and phylogeny
• Based on similarities in observable characteristics
• Other evidence for the theory of evolution

  • Fossils= allows us to compare extinct organisms to today’s organisms
  • Genomic DNA= sequencing of genomes have shown how closely related we are to primates
  • Molecular= proteins are composed of the same 20 amino acids in all organisms
• Differentiate between continuous and discontinuous variation

  Continuous= variation exists as gradations
• What is the difference between classification and phylogeny?

  Classification is simply sorting organisms into groups. Phylogeny investigates the evolutionary relationships between organisms.
• What causes variation?

  1. Genetic= mutations, random fertilisation, etc

  2. Environmental= climate, diet, culture, etc
• Explain how natural selection results in evolution

  1. Random mutations result in new alleles

  2. Some alleles provide an advantage against selection pressures, making an individual more likely to survive and reproduce

  3. Their offspring receive the new allele, and are said to have ‘evolved’ a new characteristic
• How did Darwin and Wallace contribute to the theory of evolution?

  1. Observed that birds have many different beak shapes

  2. Concluded that birds with beak shapes most suited to the food they eat are more likely to survive and therefore pass this beak shape onto their offspring
• Differentiate between intraspecific and interspecific variation

  • Intraspecific= variation within the same species
  • Interspecific= variation between different species
• Give some implications of evolution for humans
• To measure correlation between two variables, i.e. the extent to which changing one variable affects the other variable
• Types of adaptation

  • Anatomical (changes to body structure) e.g. oily fur
  • Physiological (changes to bodily processes) e.g. venom production
  • Behavioural (changes to actions) e.g. hibernation
• Interpretation of Spearman’s rank results

  • Closer to 1= more positive correlation
  • Closer to -1= more negative correlation
  • Around 0= no correlation
• Why might we calculate a Spearman’s rank correlation coefficient?
• Marsupial moles and placental moles live in different continents, but share similar anatomical features because they adapted to similar environments
• Why might organisms from different taxonomic groups show similar features?
• Implications of evolution for humans

  • Bacterial antibiotic resistance means infections are harder to treat
  • Pesticide resistance means entire crops could be destroyed
• Types of variation

  • Continuous: Variation exists as gradual changes over a range e.g. height, root length
  • Discontinuous: Variation exists as distinct categories e.g. blood group, bacteria shape
• Explain how Spearman’s rank results are interpreted