Module 4.2.2- Classification and evolution

    Subdecks (1)

    Cards (75)

    • Taxonomic group
      the hierarchical groups of classification - domain, kingdom, phylum, class, order, family, genus, species
    • Domain
      A taxonomic category above the kingdom level. The three domains are Archaea, Bacteria, and Eukarya.
    • Species
      A group of similar organisms that can breed and produce fertile offsprings.
    • NAMING SPECIES - THE BINOMIAL SYSTEM
    • Advantages of binomial system

      avoids confusion of common namesinternational in usename is descriptive and often shows relationships
    • Five Kingdoms
      Prokaryotae -> Protista -> Plantae -> Fungi -> Animalia
    • Prokaryotae Kingdom
      lack a nucleus and membrane-bound organelles, contain a nucleoid region where a loop of circular DNA is located, unicellular lack organelles
    • Protoctist Kingdom
      Unicellular and multicellular
      have nuclei
      may contain chloroplasts
    • Fungi Kingdom
      eukaryotic kingdom of heterotrophic decomposers with cell walls made of chitin
      eukaryotes, mainly multicellular, parasitic (saprophytic)symbiotic, no chloroplasts
      store food as glycogen
    • Plantae Kingdom
      Kingdom of multicellular photosynthetic autotrophs that have cell walls containing cellulose
      All contain chlorophyll
      Store food as starch
    • Animalia Kingdom
      kingdom of multicellular eukaryotic heterotrophs whose cells do not have cell walls
      no chloroplasts
      food stored as glycogen
    • What happens in Woese's system for prokaryotae?

      It is split in 2 into Archaebacteria and Eubacteria.
    • Archaebacteria
      kingdom of unicellular prokaryotes whose cell walls do not contain peptidoglycan
      can live in extreme environments
    • Eubacteria
      Kingdom of unicellular prokaryotes whose cell walls are made up of peptidoglycan
      found in all environments
      common
    • Phylogeny
      evolutionary relationships between organisms
    • Phylogenetic tree

      A family tree that shows the evolutionary relationships thought to exist among groups of organisms
    • How to interpret phylogenetic trees
      - earliest species found at the base
      - most recent species found at the tip of the branches
      - the closer the branches of the trees are, the closer the evolutionary relationships
      - two descendants that split off from the same node are called sister groups
    • Advantages of phylogenetic classification
      - Produces continuous trees as opposed to discrete taxonomical groups, so scientists are forced to fit organisms into a group where it doesn't quite fit
      - The hierarchal nature of Linnaean classification can be misleading as it implies that different groups within the same rank are equivalent (e.g. older or more diverse)
    • evidence for Evolution
      1. Fossil Record (paleontology)
      2. Comparative anatomy
      3. Comparative biochemistry
    • How do fossils (paleontology) provide evidence for evolution
      - simple organisms found in old rocks and more complex organisms found in more recent rocks
      - plant fossils appear before animal fossils
      - studying similarities in anatomy
      - allow relationships between extinct and living organisms to be investigated
    • Disadvantages to using fossils for evidence of evolution

      - they are incomplete
      - fossils destroyed
      - decompose quickly
    • Comparative anatomy
      the study of similarities and differences in the anatomy of different species
    • Homologous structures- comparative anatomy

      Structures in different species that are similar because of common ancestry. e.g. pentadactyl limb
      Have the same underlying structure
    • What type of evolution do homologous structures provide evidence for?

      Divergent evolution
    • Divergent evolution
      when two or more species sharing a common ancestor become more different over time
    • Comparative biochemistry
      Study of similarities and differences in biochemical makeup of organisms
    • What are the two most common molecules studies for comparative biochemistry

      Cytochrome c and ribosomal RNA
    • How does comparative biochemistry provide evidence for evolution

      To discover how closely two species are related, the molecular sequence of a particular molecule is compared e.g. the order of DNA bases
      The number of differences are then plotted against the rate the molecule undergoes neutral base pair substitutions
      Ribosomal RNA has a very slow rate of substitution
    • Variation
      The differences in characteristics between organisms
    • Interspecific variation
      variation among members of different species
    • Intraspecific variation
      variation among members of the same species
    • Two types of variation
      Genetic and environmental
    • Genetic causes of variation

      Alleles mutations meiosis sexual reproduction chance
    • Environmental causes of variation

      Climate diet accidents culture lifestyle.
    • Discontinuous variation
      the variation in phenotypic traits in which types are grouped into discrete categories with no in-between values. e.g. male and female
    • How can discontinuous variation be represented graphically?

      Bar chart or pie chart
    • Continuous variation
      Can take any value within a range e.g. height and mass
    • How can continuous variation be represented graphically?

      Frequency table the can be plotted on a histogram
      Curve can be drawn to show the trend
    • Normal distribution curve
      the bell-shaped curve that results from plotting continuous variation data on a graph.
    • Features of normal distribution
      - mean, mode and median are the same
      - bell shaped- 50% below and above the mean
      - most values lie close to the mean