CLASSIFICATION OF LIVING THINGS TAXONOMY SBI3U A Good Classification 1. It groups together all things that are similar. 2. It excludes all things that are dissimilar. 3. It serves a function. TAXONOMY IS… the science of discovering naming organisms describing classifying TAXONOMY IS to understand biodiversity (and more…) Taxonomy from Greek words: taxis = division/arrangement; nomos = law DISCOVERING The discovery of new organisms is the first step of taxonomy. Every year, new discoveries are made throughout the world, as taxonomists explore new areas, or new TAXONOMY IS tools become avail- Dracula fish able for analyzing Danionella dracula specimens. Discovered in Burma Documented 2009 © Ralf Britz | Natural History Museum, London NAMING Electrolux addisoni (Compagno & Heemstra, 2007) What’s in a name? A scientific name is the passport by which all organisms are known. TAXONOMY IS Photo: Phil Heemstra | Wikimedia Commons Not your average vacuum cleaner! DESCRIBING Part of this process involves the comparison to related organisms to confirm if the species is new. TAXONOMY IS Hypsiboas calcaratus (Troschel, 1848) | Photo: P. J. R. Kok CLASSIFYING Kingdom - Animalia Phylum - Chordata Class - Mammalia Order - Artiodactyla Family – Bovidae Genus - Ovis Species - Ovis aries TAXONOMY IS LINNAEUS "If you do not know the names of things, the knowledge of them is useless" Critica Botanica 1737 Carl von Linné (or Carl von Linné, 1707-1778 Linnaeus), the “father Drawing: AMNH Library of taxonomy”, laid the Linnaeus gave classification the foundations for the consistency and precision we need when we describe bio- NAMES MATTER MATTER NAMES modern scheme of diversity, trade commodities, nomenclature - the buy seeds for farming, manage pests, or deal with any other of discipline of naming the many areas in which species. humans need taxonomic knowledge. Carolus Linnaeus • Described organisms with two word names • Developed binomial nomenclature • First word = genus name • Second word = species name Modern classification is based on the 18th century work of Carolus Linneaus • Organisms are assigned to groups called “taxa” (sing. “taxon”) • Taxa are hierarchically arranged • Each subsequent taxon contains fewer species than the preceding taxon • Only members of “species”, the smallest taxon, are able to produce fertile offspring Why binomial nomenclature? • Much easier than a 10+ word name under old “polynomial system” • Same name no maer where you go • Less confusion • Binomial = SCIENTIFIC NAME What is a species anyway? • Biological species concept – A group of actually or potenLally breeding natural groups that are reproducLvely isolated from other groups. » Ernst Mayr, 1924 • BSC’s problems – Hybrids • Sterile offspring of two different species – Asexual organisms ScienLfic Names You May be familiar with • Homo sapiens • Canis lupus • Felis domes0cus All organisms classified in a hierarchy • Kingdom (broadest) • Phylum • Class • Order • Family • Genus • Species (most specific) ↓KINGDOM ↓ PHYLUM ↓ CLASS ↓ ORDER ↓ FAMILY ↓ GENUS ↓ SPECIES ACRONYM: KINGS PLAY CHESS ON FINE GREEN SAND ↓ ANIMALIA ↓ CHORDATA ↓ MAMMALIA ↓ CARNIVORA ↓ ODOBENIDAE ↓ ODOBENUS ↓ Odobenus rosmarus Common Name: Walrus IDENTIFICATION OF ORGANISMS Dichotomous Key… Ø Biological key Ø A series of branching two-part statements used to identify organisms (or objects) Ø Each step offers two mutually exclusive options designed to divide one group of organisms into two smaller groups Ø Can be used to identify organisms using visual information alone Characteristics – organized either: A)Spider Key à similar to a tree diagram List Structure .