Classification Chapter 18
Why Classify? What’s in a name? • In order to name and group organisms in a logical manner we must arrange them according to similarities and differences. Usually from physical characteristics or DNA/Protein sequencing. • Taxonomy- classifying organisms and assigning each a name – according to their characteristics, physical traits. • Scientists that classify living organisms are called Taxonomists.
Do you organize? • Think of your house: • Is there a logical set up? Is it organized? • Your clothes? Do you have them arranged by season? By color? By style? • School work, do you organize it by subject? A day or B day? • All of us organize in some way. Choosing the arrangement by our personal needs and aesthetics.
Assigning Scientific Names • Early Efforts- described physical characteristics • Carolus Linnaeus – Botanist and Naturalist • Developed the current 7 category naming system we use today. • Did not agree with Darwin’s Theory of Evolution through natural Descent, but understood that similar organisms shared similar traits. • Binomial Nomenclature: • two word naming system, the Genus and species • Genus – capitalized, • species – never capitalized • Abbreviated to – G. spp. • Always typed in italics • Underlined when written Genus species • Homo sapien – modern humans • H. sapien
Linnaeus’s System (7 categories) • Kingdom • Phylum • Class • Order • Family • Genus • Species Broad characteristics (unique & grouped) to Narrow characteristics (Specific & individual)
Kingdom K Phylum Ph class C order O F Family G Genus S species
Grizzly bear Black bear Giant panda Red fox Abert squirrel Coral snake Sea star KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER Carnivora FAMILY Ursidae GENUS Ursus SPECIES Ursus arctos
Ursus maritimus Ursus arctos When written or typed the genus is always capitalized and the species is not
Evolutionary Classification • Phylogeny- study of evolutionary relationships among organisms • Biologists classify organisms by grouping them according to evolutionary descent, not physical characteristics.
Cladograms • Uses derived characteristics to show evolutionary relationships among a group of organisms
Conical Shells Crustaceans Appendages Gastropod Crab Barnacle Limpet Crab Barnacle Limpet Molted exoskeleton Segmentation Tiny free-swimming larva CLADOGRAM CLASSIFICATION BASED ON VISIBLE SIMILARITIES
Kingdoms and Domains pg 459 Classification of Living Things DOMAIN KINGDOM CELL TYPE CELL STRUCTURES NUMBER OF CELLS MODE OF NUTRITION EXAMPLES Bacteria Eubacteria 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
DOMAIN ARCHAEA Kingdoms DOMAIN EUKARYA Eubacteria Archaebacteria Protista Plantae Fungi Animalia DOMAIN BACTERIA
Identify through Dichotomous Key • Used to identify organisms based on physical characteristics. • A series of paired statements are used to separate characteristics of different organisms. • From the simple: To the complex: Texas Wildlife – Turtles Texas Plants – NRCS Interactive