Unity and Diversity of Living Things Survey of Taxonomy and the Three Domains of Life

SYSTEMATICS Systematics - science of naming and grouping organisms by their evolutionary relationships Binomial Nomenclature - assigning scientific names Each species is assigned a two-part scientific name, usually in Latin, written in italics or underlined. First word (genus name) is capitalized, the second word (species name) is not. EX/ polar bear = Ursus maritimus Red maple = Acer rubrum Human = Homo sapiens

LEVELS OF CLASSIFICATION Domain (most inclusive) Kingdom Phylum Class Order Family Genus Species (least inclusive)

DOMAINS OF LIFE 3 Domains of Life Archaea (prokaryotic) Bacteria (prokaryotic) Eukarya (eukaryotic)

DOMAIN BACTERIA Prokaryotic Unicellular Cell walls contain peptidoglycan Ecologically diverse ranging from free-living soil organisms to deadly parasites. Some autotrophic, some heterotrophic Some need oxygen to survive (aerobic), some are killed by oxygen (anaerobic) Only one kingdom within this domain: Kingdom Eubacteira

DOMAIN ARCHAEA Prokaryotic Unicellular Cell walls do NOT contain peptidoglycan Live in very harsh environments Some autotrophic, some heterotrophic Some need oxygen to survive (aerobic), some are killed by oxygen (anaerobic) Only one kingdom within this domain: Kingdom Archaebacteira

IMPORTANCE OF PROKARYOTES 1) Ecological Importance: Essential in maintaining every aspect of the ecological balance of the living world Decomposers – recycling raw materials to the environment, essential to sewage treatment & production of purified water Producers – cyanobacteria are among the most plentiful photosynthetic organisms in the world & many food chains are dependent upon them Nitrogen Fixers – converting nitrogen gas into useable forms 2) Human Uses Food – yogurt, other dairy products Medicine – making drugs for medical treatments 3) Disease – some bacteria can cause disease by destroying living cells or by releasing chemicals that upset homeostasis EX’s/ Lyme disease, Tetanus, Tuberculosis, Strep Throat Controlled by sterilization, disinfectants Prevented by vaccines

DOMAIN EUKARYA All Eukaryotes: contain a nucleus & other membrane-bound organelles Four Kingdoms Protista (protists) Fungi Plantae Animalia

PROTISTS Unicellular, Colonial, or Multicellular Photosynthetic or Heterotrophic Catchall kingdom – group of eukaryotes that did not fit into plants, animal or fungus kingdom

ECOLOGICAL IMPORTANCE OF PROTISTS Autotrophic Protists – photosynthetic protists at the base of the food chain makes much of the diversity of aquatic life possible EX/ Algae Heterotrophic Protists – some heterotrophic protists engulf and digest their food, while others live by absorbing molecules from the environment. EX/ Paramecium, amoeba Symbiotic Protists Mutualistic – algae help health of coral reefs, Trichonympha live in guts of termites, helping them to digest cellulose Parasitic – can cause intestinal disease, African Sleeping Sickness, & Malaria Red blood cell

FUNGI Heterotrophic – feed on dead or decaying organic matter Secrete digestive enzymes into their food source, then absorb nutrients though their cell walls Cell walls made of chitin Unicellular (yeasts) or Multicellular (mushrooms)

ECOLOGICAL IMPORTANCE OF FUNGI Decomposers – many species of fungi help ecosystems maintain homeostasis by breaking down dead organisms and recycling essential elements and nutrients. Parasites – parasitic fungi can cause serious diseases in plants and animals EX/smuts and rusts in plants Athlete’s foot & ringworm Symbiotic Fungi: Lichens – mutualistic association between a fungus and a photosynthetic partner (algae or cyanobacteria). Are often the first organisms to enter barren environments and help in early stages of soil formation. Michorrhizae – mutualistic association between a fungus and a plant root. Estimates that 80-90% of all plant species have this sort of relationship. Fungus collects water and minerals, bringing them to the root, plant supplies the fungi with the products of photosynthesis (sugars).

PLANTS Multicellular Cell walls with cellulose Autotrophic Have chloroplasts

ANIMALS Multicellular Heterotrophic No cell walls Most can move