classification and evolution

• classification benefits

  • convenience
  • easier to identify organisms
  • helps see relationships between organisms
• taxonomic hierarchy

  1. domain
  2. kingdom
  3. phylum
  4. class
  5. order
  6. family
  7. genus
  8. species
• 1. domain - most inclusive
  2. kingdom
  3. phylum
  4. class
  5. order
  6. family
  7. genus
  8. species - least inclusive
• domain


  eukaryotes, bacteria, archae
• archae


  prokaryotic organisms - used to be classified as bacteria but have unique properties separating them from other two domains
• kingdoms

  1. animalia
  2. plantae
  3. fungi
  4. protoctista
  5. prokaryotae
• prokaryotae

  • single - celled
  • loop of DNA in cytoplasm
  • no membrane bound organelles
  • small ribosomes
• protoctista

  • eukaryotic
  • multi-celled and single-celled
  • plant and animal like
  • can be autotrophic and heterotrophic
• fungi

  • multi-cellular
  • eukaryotic
  • plant and animal like
  • heterotrophic
  • autotrophic
  • single-celled
  • saprophytic
• plantae

  • multi-cellular
  • walls of chitin
  • eukaryotic
  • has multi-nucleate cytoplasm
  • saprophytic
  • autotrophic
  • cellulose
  • cell wall
• animalia

  • multi-cellular
  • move around
  • eukaryotic
  • multi-nucleate cytoplasm
  • heterotrophic
• autotrophic


  make own food
• heterotrophic


  go out and find food
• saprophytic


  feed on decaying/dead material
• binomial naming system

  • genus name followed by species name
  • print= italics; handwritten = underlined
  • genus= uppercase, species name= lower case
• phylogeny


  study of evolutionary relationships between species
• convergent evolution


  unrelated species can adapt to their environment in similar ways and therefore look very similar. - even though they aren't closely related e.g sharks and dolphins
• evidence used in classification - biological molecules - DNA

  • dna sequences change at random overtime (mutations)
  • more similar a dna sequence between species - more related they are
• evidence used in classification - protein (cytochrome c)

  • cytochrome c is a protein used in respiration (all living things have it)
  • more similar the cytochrome c amino acid sequences between species, the more closely related they are
• variation


  differences between individual organisms
• interspecies variation


  differences between species
• intraspecies variation


  differences within a species
• discontinuous variation

  two or more distinct categories
• continuous variation


  variation within a range (no distinct categories)
• human applications of natural selection

  1. antibiotic resistant bacteria
  2. pesticide resistance in insects
• students t test

  • compare 2 means to see if difference between 2 sets of data are significant
• degrees of freedom


  (n1 + n2) - 2
• standard deviation is a measure of variation

  • low SD - data has narrow range - high reliability
  • high SD - data has large range - less grouped - low reliability
• spearmans rank


  -1 = perfect negative correlation

  0 = no correlation

  +1 = perfect positive correlation
• what causes variation?

  • genetic (inherited factors): allele combinations make up an organisms genotype
  • environmental factors: difference in the environment can result in variation
• adaptation

  any trait that increases an organisms chance of survival
• types of adaptations:

  • behavioural adaptations - the way an organism behaves to increase survival e.g moving herds
  • physiological behaviours - processes inside an organisms body to increase survival e.g dessert plants close stomata during the day
  • anatomical features - structural features of an organisms body e.g male peacocks are colourful
• factors that affect evolution by natural selection

  • genetic variation
  • reproductive success - survival of individuals - passing on genes
  • selection pressure - environmental change
• Standard deviation equation

  
• Spearman’s rank equation

  
• T test equation

  
• Phylogenetic tree