The variety of life

  1. What are species, families, domains?
    • What are the Two domains of life?
  2. What is the history of Life on Earth
    Any discussion of biodiversity should begin with the The Tree of Life
    You should also have a look at the Endangered Species Page (U.S. Fish & Wildlife Service)

      <= BACK     ^ TOP         NEXT =>










What is a species?

    • a species includes sexually reproducing organisms that, when they breed, produce live, fertile offspring
    • Example: horses & donkeys Equus species,
      but not mules zorse 2
    • Example: blue & foothills paloverde Parkensonia

<= BACK     ^ TOP         NEXT =>








Formal (Latin) species names vs. common names

    • Formal names are unique, based on detailed descriptions & international
            Ursus horribilis [Wikipedia] --> &
            Homo neanderthalensis [New Anatomist]
    • Common names are NOT unique, and local. What a Californian calls a ' bumblebee,' an easterner calls a 'yellow jacket,'
      Ex: Fouquieriaceae Fouquieria splendens
         Spanish "Ocotillo," Engl. "Coach whip."

<= BACK     ^ TOP         NEXT =>








Taxonomy above the Species

      • Kingdom-- Animalia (animals) (below domains)
      • Phylum--Chordata (have notochord)
      • Class--Mammalia (nurse young)
      • Order--Primates (ex: lorises, monkeys, apes)
      • Family--Hominidae (ex: Homo, Pan, Gorilla)
      • Genus--Homo (ex: sapiens, neanderthalensis, erectus)
      • Species--sapiens
        • Subspecies--sapiens

    * Homo sapiens
    Taxonomy Examples

<= BACK     ^ TOP         NEXT =>








Two Domains:








Origin of life (what is life)


<= BACK     ^ TOP         NEXT =>








    Biological evolution I
  • 3.8-2.1 billion years ago (Archean)


  • Prokaryote World
    • Before ca. 2.32 Gyr: bacteria + archea only
      RESPIRATION only
          CH2O + O2 => H2O + CO2
    • Thereafter: Cyanobacteria (blue-green algae) PHOTOSYNTHESIS (2.32 Gyr)
         H2O + CO2 => CH2O + O2

<= BACK     ^ TOP         NEXT =>











<= BACK     ^ TOP         NEXT =>










<= BACK     ^ TOP         NEXT =>








BEGINING DATES: Evolution of Life on Earth

    • 4.7 Gy begin chem evolution
         4 Gy  RNA-world
    • 3.8 Gy begin prokaryotes
    • 2.3 Gy begin photosynthesis
    • 2.1 Gy begin eukaryotes
    • 0.65 Gy diversification of modern
    • 0.40 Gy land plants

<= BACK     ^ TOP         NEXT =>