KEY CONCEPT The current Tree of Life has Three domains and Six Kingdoms.
Classification is always a work in progress. The tree of life shows our most current understanding. New discoveries can lead to changes in classification. From 1753-1866: Linnaeus created only two kingdoms, Animalia and Plantae Animalia Plantae
Classification is always a work in progress. Until 1866: only two kingdoms, Animalia and Plantae Plantae Animalia Protista *1866: all single-celled organisms moved to kingdom Protista
Classification is always a work in progress. Until 1866: only two kingdoms, Animalia and Plantae Animalia Protista Plantae 1866: all single-celled organisms moved to Kingdom Protista Monera *1938: prokaryotes moved to Kingdom Monera
Classification is always a work in progress. New discoveries can lead to changes in classification. Until 1866: only two kingdoms, Animalia and Plantae Protista Plantae Animalia 1866: all single-celled organisms moved to Kingdom Protista Fungi 1938: prokaryotes moved to Kingdom Monera Monera *1959: Fungi moved to own kingdom
Classification is always a work in progress. Until 1866: only two kingdoms, Animalia and Plantae Animalia Protista Fungi Plantae 1866: all single-celled organisms moved to Kingdom Protista 1938: prokaryotes moved to Kingdom Monera Archea Bacteria 1959: fungi moved to own kingdom *1977: Kingdom Monera split into Kingdoms Bacteria and Archaea
The three domains in the tree of life are Bacteria, Archaea, and Eukarya. Domains are above the kingdom level. (Larger category) proposed by Carl Woese based on rRNA studies of prokaryotes domain model more clearly shows prokaryotic diversity
Domain Bacteria includes prokaryotes in the Kingdom Bacteria. one of largest groups on Earth classified by shape, need for oxygen, and diseases caused ex. Strep, E. coli, staph infection, food poisoning
Domain Archaea includes prokaryotes in the Kingdom Archaea. Ex. Halophiles , thermophiles cell walls chemically different from bacteria -Peptidoglycan differences discovered by studying RNA known for living in extreme environments (hot, salty)
Domain Eukarya includes all eukaryotes. 1. Kingdom Protista (seaweed, diatoms, amoeba…)
Domain Eukarya includes all eukaryotes. 4 Kingdoms 2. Kingdom Plantae (mosses, ferns, conifers, flowering plants…)
Domain Eukarya includes all eukaryotes. 3. Kingdom Fungi (mushroom, athlete’s foot, mold, yeast…)
Domain Eukarya includes all eukaryotes. Kingdom Animalia (sponges, jellyfish, roundworms, segmented worms, flatworms, echinoderms, mollusks, arthropods, Chordates – spinal cord such as reptiles, fishes, mammals, amphibians, birds)
Bacteria and archaea can be difficult to classify. transfer genes among themselves outside of reproduction blurs the line between “species” more research needed to understand prokaryotes bridge to transfer DNA
Figure 18-12 Key Characteristics of Kingdoms and Domain Section 18-3 Figure 18-12 Key Characteristics of Kingdoms and Domain DOMAIN KINGDOM CELL TYPE CELL STRUCTURES NUMBER OF CELLS MODE OF NUTRITION EXAMPLES Bacteria Prokaryote Cell walls with peptidoglycan Unicellular Autotroph or heterotroph Streptococcus, Escherichia coli Archaea Archaebacteria Prokaryote Cell walls without peptidoglycan Unicellular Autotroph or heterotroph Methanogens, halophiles Protista Eukaryote Cell walls of cellulose in some; some have chloroplasts Most unicellular; some colonial; some multicellular Autotroph or heterotroph Amoeba, Paramecium, slime molds, giant kelp Fungi Eukaryote Cell walls of chitin Most multicellular; some unicellular Heterotroph Mushrooms, yeasts Eukarya Plantae Eukaryote Cell walls of cellulose; chloroplasts Multicellular Autotroph Mosses, ferns, flowering plants Animalia Eukaryote No cell walls or chloroplasts Multicellular Heterotroph Sponges, worms, insects, fishes, mammals