classification and evolution

• Phylogenetic classification


  Arranges species into groups according to their evolutionary origins and relationships
• Phylogenetic classification tells us how closely related species are and how recent their shared common ancestor is
• Phylogenetic trees represent evolutionary relationships between species
• Humans and penguins are very distantly related


  Their last common ancestor is from a very long period ago, millions of years ago
• Humans and penguins evolved from a common ancestor
• Linnaeus classification hierarchy system

  1. Domain

  2. Kingdom

  3. Phylum

  4. Class

  5. Order

  6. Family

  7. Genus

  8. Species
• Taxa or taxon


  Each group in the Linnaeus classification hierarchy system
• Hierarchy


  Small groups arranged into larger groups with no overlap between them
• Members of different species within the same genus are closely related
• Binomial system


  Universally used system with two names: genus and species
• Common names can be misleading as they vary by language and are based on physical appearance, while binomial names indicate closeness in relation
• Five Kingdoms in the Linnaeus classification hierarchy system

  • Prokaryote
  • Protoctista
  • Fungi
  • Plantae
  • Animalia
• Classification systems have evolved with advances in technology, moving from physical appearances to molecular similarities for accuracy
• Changes in classification systems include comparing DNA-based sequences and amino acid sequences for molecular similarities
• Carve proposed an extra taxa above Kingdom called Domain, with three domains added in the 1990s: archaea, bacteria, and eukaryota
• Organisms are split into three domains based on RNA, ribosomes, and cell membrane structures
• Natural selection, proposed by Wallace in 1858, leads to Evolution
• Darwin's finches on the Galapagos Islands contributed to the Theory of Evolution
• Wallace proposed the theory of natural selection


  1858
• Wallace submitted his ideas to Darwin to be peer-reviewed
• Darwin was aboard the HMS Beagle prior to this conducting his own studies into this Theory
• Darwin noticed that the finches on each Galapagos Island had different shaped beaks reflecting the different food present on those islands
• Wallace and Darwin worked together to publish scientific journals in 1858
• Darwin independently published On the Origin of Species


  1856
• Darwin's theory of evolution was controversial and not widely accepted initially
• Evidence supporting Darwin's theory includes fossil DNA and molecular evidence
• Fossils are imprints or remains of dead animals and plants in rocks from a long time ago
• Fossil records provide evidence of how species have changed over time and evolved
• Comparing DNA-based sequences of common genes or other molecular evidence helps determine species relationships
• Cytochrome c is a protein found in the mitochondria used for comparing genetic relatedness
• Evolution results in species better adapted to their environment
• Types of adaptations

  • Anatomical
  • Physiological
  • Behavioral
• Anatomical adaptations are internal or external physical features
• Behavioral adaptations are changes in the way organisms act
• Physiological adaptations are processes that take place within an organism
• Convergent evolution occurs when different species are exposed to similar selection pressures
• Types of variation

  • Intra-specific
  • Inter-specific
• Intra-specific variation is genetic variation within the same species
• Inter-specific variation is differences between members of different species
• Environmental factors can cause variation in organisms