Ch.17 – Organizing Life’s Diversity 17.1 – History of Classification Taxonomy – branch of biology concerned with identifying, naming, and classifying species Based on a system developed by Carolus Linnaeus in 1748 He also developed a two-part naming system for every species Linnaeus’ system involved classifying organisms in a series of groups from large and general to smaller and more specific according to physical characteristics

Ch.17 – Organizing Life’s Diversity 17.1 – History of Classification Animalia Chordata Mamalia Primata Hominidae Homo Sapiens Used as the scientific names for all species (Binomial Nomenclature) Eukaryotic, heterotrophic, multicellular Vertebrates Milk-producing, fur/hair covered Short snouts, stereoscopic vision, nails not claws, 4 types of teeth Bipedal, large frontal lobes of brain Larger brain (>1000cc), upright forehead, shorter arms, longer legs, language, culture High forehead, small teeth and jaw, defined chin, and ability to create and appreciate art/symbols Human Classification

Ch.17 – Organizing Life’s Diversity 17.2 – Modern Classification Phylogenetic tree - shows evolutionary relationships based on similarities and differences in physical and/or genetic characteristics. There is presumed to be a common ancestor at each node and the distance between nodes indicates the passage of time Species are classified today according to physical and genetic characteristics

Ch.17 – Organizing Life’s Diversity 17.2 – Modern Classification Cladogram - shows one branch of a phylogenetic tree and focuses mainly on homologous structures of the organisms Derived trait – A trait not present in the last common ancestor being considered Ancestral trait – Traits retained from common ancestors

Ch.17 – Organizing Life’s Diversity 17.3 – Domains and Kingdoms The 3 Domains and 6 Kingdoms Plantae Animalia Fungi Protista Eubacteria Archaebacteria Archaea Bacteria Eukarya

Ch.17 – Organizing Life’s Diversity 17.3 – Domains and Kingdoms Archaebacteria Eubacteria Protista Fungi Plantae Animalia Prokaryotic Unicellular Hetero- or Autotrophic -Live in extreme environments Prokaryotic Unicellular Hetero- or Autotrophic -Most bacteria found on Earth Eukaryotic Uni- or Multicellular Hetero- or Autotrophic -Usually found in aquatic environments Eukaryotic Uni- or Multicellular Heterotrophic (Decomposers) -Absorb nutrients from other organic material Eukaryotic Multicellular Autotrophic -Have cells organized into tissues -Most are immobile Eukaryotic Multicellular Heterotrophic -Have tissues organized into organs and organ systems -Most are mobile

Ch.17 – Organizing Life’s Diversity 17.3 – Domains and Kingdoms What about Viruses? -Viruses are non-living. -They are DNA or RNA surrounded by a protein coat (capsid) and are sometimes enclosed within a membrane -A virus needs a host to reproduce -Outside of a host a virus is metabolically inert -The virus inserts its genetic material into the host, taking over the host’s functions. -An infected cell creates more viral protein and genetic material. Viruses containing RNA are called retroviruses HIV (a retrovirus)

Ch.17 – Organizing Life’s Diversity 17.3 – Domains and Kingdoms What about Viruses? -A virus may remain dormant for a period of time causing no changes in the host cell, called the lysogenic phase -But when stimulated, it enters the lytic phase: new viruses are formed, self- assemble, and burst out of the host cell, killing the cell and going on to infect other cells Viral Diseases -Common Cold -Influenza -Chicken Pox -Herpes (I & II) -AIDS