Biological Diversity

Origin and History of Life on Earth

• Primitive earth
  • heat, energy, uv radiation, volcanic eruptions
  • atmosphere: water vapor, N₂, CO₂, CO
  • no oxygen in atmosphere
  • Stanley Miller's experiment
  • formation of cells
  • evolution of the cell
  • origin of eukayotic cell - endosymbiont hypothesis

Systems of Classification

• Carolus Linnaeus
• taxonomic hierarchy
• 3-domain system

Domain Eubacteria

• most abundant organisms and widest variety of habitats
• characteristics of all prokaryotes
• structural features
• size and shapes
  1. coccus
  2. bacillus
  3. spirillum
• metabolic diversity
  • heterotrophic
    • "good species"
    • "bad species" - pathogens
    • decomposers
  • autotrophic
    1. chemoautotrophic
    2. photoautotrophic

Domain Archaea

• prokayotic cells
• most ancient of cells
• chemoautotrophs
• types:
  • methanogens - "methane makers"
  • halophiles - "salt lovers"
  • extreme thermophiles - "heat lovers"

Viruses

• characteristics of viruses
  1. non-cellular infectious agent
  2. protein coat wrapped around nucleic acid
  3. cannot reproduce on their own
• reproduction of viruses
  1. lytic cycle
  2. lysogenic cycle

Domain Eukarya

• origin of eukayotic cell - endosymbiotic hypothesis
• Kingdom Protista
• Kingdom Fungi
• Kingdom Animalia
• Kingdom Plantae

Kingdom Protista

• characteristics
  • structurally most simple eukaryotes
  • unicellular to multi-cellular
  • most are motile
  • many use asexual reproduction
  • autotrophs and heterotrophs
  • gave rise to the other kingdoms
  • all still living in water or moist environments
• parasitic molds (fungal-like protists)
  • most are saprobes or parasites
  • examples
• protozoans and sporozoans (animal-like protists)
  • unicellular
  • heterotrophs
  • may be parasitic or cause disease
  • examples
• algae (plant-like protists)
  • unicellular to multi-cellular
  • photosynthetic autotrophs
  • examples

Kingdom Fungi

• characteristics
  • eukaryotes
  • most are multi-cellular
  • heterotrophs
    • secrete digestive enzymes and absorb the nutrients released
    • saprobes - nutrients from non-living, organic matter
    • parasites - nutrients from living organisms
  • may reproduce sexually or asexually
  • produce spores (adaptation for life on land)
  • cell wall (adaptation for life on land)
  • fungus is composed of hyphae
  • hyphae make up the mycelium
• major groups (based on how they make their spores)
  • zygospore fungi
    • includes bread mold
    • human impact
    • fungal life cycle
  • sac fungi
    • includes morels and yeasts
    • human impact
  • club fungi
    • includes mushrooms, shelf fungi, coral fungi, puffballs
    • important decomposers
    • human impact
• symbiotic relationships
  • 2 organisms living together and both benefit
  • lichens
    • usually sac fungus and cyanobacteria
    • live in hostile environments
    • fungus gets nutrient source
    • cyanobacteria get shelter
  • mycorrhizae
    • between fungus and plant roots
    • fungus gets sugars
    • plant gets minerals

Kingdom Animalia

• characteristics
  • all multi-cellular
  • usually motile
  • heterotrophs that ingest food
  • many have moved into land
• evolutionary relationship of animals
• invertebrates
  • sponges - no symmetry
  • cnidarians - radial symmetry
  • flatworms - bilateral symmetry and tubular gut
  • roundworms - pseudocoelom
  • molluscs - mantle
  • annelids - segmented body
  • arthropods - exoskeleton and jointed appendages
  • echinoderms - endoskeleton and radial symmetry
• chordates - dorsal nerve cord and tail
• vertebrates - internal bony or cartilagenous skeleton
  • fishes - gills
  • amphibians - limbs, lungs, spend part of their life in water
  • reptiles - shelled, amniotic egg, dry, scaly skin, can live whole life out of water
  • birds - feathers
  • mammals - hair and mammary glands

Kingdom Plantae

• characteristics
  • eukaryotic
  • multi-cellular
  • not motile
  • photoautotrophic
  • life cycle requires the production of haploid spores
• ancestors were algae
• adaptations for life on land
• bryophytes
  • mosses
  • no roots, stems, or leaves
  • no transport system
  • require water for fertilization
  • dominant haploid stage
• seedless vascular plants
  • ferns and fern allies
  • true roots, stems, and leaves
  • have transport system
  • require water for fertilization
  • dominant diploid stage
• gymnosperms
  • conifers
  • very complex vascular system
  • fertilization with pollen grain
  • produce seeds
  • dominant diploid stage
• angiosperms
  • flowering plants
  • complex vascular system
  • fertilization with pollen
  • flowers
  • seeds are inside fruits

© Carol L. Wymer, 2004