Transcript 2) Species
Honors Biology Ch.17 Organizing Life’s Diversity I. The History of Classification Taxonomy: - the science of identifying, naming, and classifying organisms A. Early Classification Systems 1. Aristotle: a. Devised First Classification System - Animals (red-blooded and bloodless) - Plants (trees, shrubs, and herbs) - 2 problems: 1) superficial categories 2) used common names B. Disadvantages of Common Names: 1.Confusing - ex. mountain lion, cougar, puma, panther, catamount Puma concolor 2.Misleading - ex. starfish, jellyfish, cuttlefish, crawfish, silverfish 3.Language Problems - local names - names used by different languages - some organisms have no common name Microplitis demolitor 2. Carolus Linnaeus - developed modern classification system - Swedish botanist (1700’s) - 2 important innovations: a. Binomial Nomenclature - two-word naming system: genus & species - gives a unique, universal name for every species Carolus Linnaeus Honey Bee Apis mellifera Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis glabris, utrinque margine ciliatus 1) Genus: - 1st word, small group - usually a Latin noun, capitalized 2) Species: - 2nd word, particular type - Latin adjective, lower case 3) Examples: - Homo sapiens - Tyrannosaurus rex humans 3) Examples: - Acer macrophyllum - Acer rubrum - Acer saccharum bigleaf maple red maple sugar maple Acer pennsylvaticum Acer rubrum Acer saccharum Acer circinatum 3) Examples: - Sequoia gigantum - Tsuga heterophyllum - Pseudotsuga menziesii giant sequoia western hemlock Douglas-fir b. Hierarchy of Classification Groupings Domain Kingdom Phylum Class Order Family Genus Species Eukarya Animalia Chordata Mammalia Carnivora Canidae Canis lupus b. Hierarchy of Classification Groupings Did Domain Eukarya King Kingdom Animalia Phillip Phylum Chordata come Class Mammalia often Order Carnivora for Family Canidae ginger Genus Canis snaps? Species lupus Hierarchy of Taxa II. Taxonomy Today - Classification systems change constantly. - Taxonomists do not always agree on how to classify organisms. A.Determining Species 1. Typological Species Concept - a group of organisms that are physically similar to each other 2. Biological Species Concept - a group of organisms that is able to interbreed and produce fertile offspring in a natural setting - cannot be used with extinct or asexual organisms Similarity between different species Diversity within a species 3. Phylogenetic Species Concept - defines a species as a set of organisms with a unique genetic history B. Characters - inherited features (morphological or biochemical) that vary among organisms 1. Morphological Characters - similarities indicate common ancestry - include homologous structures: different functions but have similar underlying anatomy - does not include analogous structures: similar functions but different underlying anatomy Marsupial ‘Mole’ Eastern Mole 2. Biochemical Characters - The greater the similarities in certain compounds (DNA, proteins, etc.), the more closely related organisms are. Species Percent of Amino Acids That Are Identical to the Amino Acids in a Human Hemoglobin Polypeptide 100% Human Rhesus monkey 95% Mouse 87% Chicken 69% Frog Comparison of a Protein Found in Diverse Vertebrates Lamprey 54% 14% A Molecular Homology 3. Molecular “Clock” - Mutations occur randomly and accumulate over time. - Mutations that don’t affect survival can be used to estimate time. The Constant Rate of Evolution of the α-globin C. Phylogenetic Reconstruction - Phylogeny is the evolutionary history of a species. Phylogeny of Whales 1. Character Types - Ancestral characters are shared by ancestral organism and all of its descendents. - Derived characters are Leopard Turtle shared by one group Hair Salamander of organisms Amniotic egg but not the Tuna ancestor. Four walking legs Lamprey Hinged jaws Lancelet (outgroup) Vertebral column Phylogenetic Tree of Chordates 2. Cladograms (Phylogenetic Tree) - a branching diagram that represent the proposed phylogeny of a group of organisms Phylogenetic Tree of Dinosaurs Ursininae Tremarclinae Ailuropodinae Procyonidae Ailuridae Ursidae Phylogeny of Bears Musteloidae Caniformia III. Domains and Kingdoms - Most scientists today use the 3 domain system to classify organisms: Bacteria, Archaea, and Eukarya. EUKARYA Dinoflagellates Forams Diatoms Ciliates Red algae Land plants Green algae Cellular slime molds Amoebas Euglena Trypanosomes Leishmania Animals Fungi Sulfolobus Green nonsulfur bacteria Thermophiles Halophiles (Mitochondrion) COMMON ANCESTOR OF ALL LIFE Methanobacterium ARCHAEA The Three Domains of Life Spirochetes Chlamydia Green sulfur bacteria BACTERIA Cyanobacteria (Plastids, including chloroplasts) A.Domain Bacteria - includes the kingdom Eubacteria - prokaryotes whose cell walls contain peptidoglycan B.Domain Archaea - Prokaryotes that represent an ancient form of life - more closely related to our eukaryotic ancestors - called extremophiles because they can live in extreme environments C. Domain Eukarya - includes all eukaryotes - contains: Kingdom Protista Kingdom Plantae Kingdom Fungi Kingdom Animalia 1.Kingdom Protista - eukaryotic organisms - unicellular, colonial, or multicellular 2.Kingdom Plantae - photosynthetic multicellular eukaryotes - have cell walls made of cellulose - nonmotile 3. Kingdom Fungi - unicellular or multicellular eukaryote heterotrophic (absorb nutrients) have cell walls made of chitin nonmotile 3. Kingdom Fungi - unicellular or multicellular eukaryote - heterotrophic (absorb nutrients) - have cell walls made of chitin - nonmotile 4.Kingdom Animalia - heterotrophic, multicellular eukaryotes - complex organ systems - motile - obtain food by ingestion The End - Order Carnivora Linking Classification and Phylogeny Order Family Genus Species Taxidea Taxidea taxus Lutra Mustelidae Panthera Felidae Carnivora Panthera pardus Lutra lutra Canis Canidae Canis latrans Canis lupus A Phylogenetic Tree of Birds and Their Close Relatives Lizards and snakes Crocodilians Common ancestor of crocodilians, dinosaurs, and birds Ornithischian dinosaurs Saurischian dinosaurs Birds Phylogeny of Horses Recent (11,500 ya) Equus Pleistocene (1.8 mya) Hippidion and other genera Nannippus Pliohippus Hipparion Neohipparion Pliocene (5.3 mya) Sinohippus Megahippus Callippus Archaeohippus Miocene (23 mya) Merychippus Hypohippus Anchitherium Parahippus Miohippus Oligocene (33.9 mya) Mesohippus Paleotherium Epihippus Propalaeotherium Eocene (55.8 mya) Pachynolophus Orohippus Key Hyracotherium Grazers Browsers