Transcript Ch 17 PPT
Classification Chapter 17 1 Species of Organisms 17-1 •There are 13 billion known species of organisms •1.75 million have been named and described by scientists. •This is only 5% of all organisms that ever lived!!!!! •New organisms are still being found and identified 2 What is Classification? Classification is the arrangement of organisms into orderly groups based on their similarities Classification is also known as taxonomy Taxonomists are scientists that identify & name organisms 3 Benefits of Classifying •organisms Accurately & uniformly names •starfish Prevents misnomers such as & jellyfish that aren't really fish Uses same language (Latin or some Greek) for all names • Sea”horse”?? 4 Confusion in Using Different Languages for Names 5 Latin Names are Understood by all Taxonomists 6 Early Taxonomists •2000 years ago, Aristotle was the first taxonomist Aristotle divided organisms into plants & animals He subdivided them by their habitat ---land, sea, or air dwellers • • 7 Early Taxonomists •John Ray, a botanist, was the first to use Latin for naming His names were very long descriptions telling everything about the plant • 8 Carolus Linnaeus 1707 – 1778 • 18th century taxonomist • Classified • organisms by their structure Developed naming system still used today 9 Carolus Linnaeus •Called the “Father of Taxonomy” •Developed the modern system of naming known as binomial nomenclature Two-word name (Genus & species) • 10 Standardized Naming •Binomial nomenclature used •Genus species •Latin or Greek •Italicized in print •Capitalize genus, but NOT species •Underline when Turdus migratorius writing American Robin 11 Binomial Nomenclature Which TWO are more closely related? 12 Classification Groups • Taxon ( taxa-plural) is a • • category into which related organisms are placed There is a hierarchy of groups (taxa) from broadest to most specific Domain, Kingdom, Phylum, Class, Order, Family, Genus, species 13 Hierarchy-Taxonomic Groups BROADEST TAXON Domain Kingdom Phylum (Division – used for plants) Class Order Family Genus Species Most Specific 14 Daring King Phillip Came Over For Gooseberry Soup! 15 16 Taxons 17-2 •Most genera contain a number of similar species •The genus Homo is an exception (only contains modern humans) Classification is based on evolutionary relationships • 17 Determining Species • Typological Species Concept –Looks at physical characteristics –Limited due to variation of alleles for traits • Biological Species Concept –Looks at similarity in characteristics and the ability to breed fertile offspring –Limited due to not all separate species are unable to breed (i.e. wolves and dogs) • Phylogenetic Species Concept –Looks at evolutionary history –Limited due to unknown histories for some species 18 Basis for Modern Taxonomy •Homologous (morphological characters) structures (same structure, different function) Similar embryo development Molecular Similarity (biochemical characters) in DNA, RNA, or amino acid sequences in Proteins • • 19 Homologous Structures (BONES in the FORELIMBS) shows Similarities in mammals. 20 Similarities in Vertebrate Embryos 21 Cladogram Diagram showing how organisms are related based on shared, derived characteristics such as feathers, hair, or scales 22 • As animals evolve, they derive new features, or characteristics. • A derived characteristic can be any attribute of an animal, from the shape of its bones and muscles to its genetic chemistry and DNA. +/- Table 0/1 Table Cladogram Primate Cladogram 25 Dichotomous Keying •Used to identify organisms •Characteristics given in pairs •Read both characteristics and either go to another set of characteristics OR identify the organism 26 Example of Dichotomous Key 1a 1b 2a 2b 3a 3b 4a 4b Tentacles present – Go to 2 Tentacles absent – Go to 6 Eight Tentacles – Octopus More than 8 tentacles – 3 Tentacles hang down – go to 4 Tentacles upright–Sea Anemone Balloon-shaped body–Jellyfish Body NOT balloon-shaped - 5 27 1. a. wings covered by an exoskeleton ………go to step 2 b. wings not covered by an exoskeleton ……….go to step 3 2. a. body has a round shape ………. Coccinella septempunctata b. body has an elongated shape ………. Camnula pellucida 3. a. wings point out from the side of the body ………. Aeshna cyanea b. wings point to the posterior of the body ………. Musca domestica Making a Dichotomous Key • Tree • Dichotomous Key 29 Domains 17-3 • Broadest, most inclusive taxon • Three domains • Archaea and Eubacteria are • unicellular prokaryotes (no nucleus or membrane-bound organelles) Eukarya are more complex and have a nucleus and membranebound organelles 30 3 Domains The Six Kingdoms Animalia Plantae Protista Eubacteria Archaebacteria Ancient common ancestor Fungi ARCHAEA • Probably the 1 cells to evolve • Live in HARSH environments • Found in: st –Sewage Treatment Plants –Thermal or Volcanic Vents –Hot Springs or Geysers that are acid –Very salty water (Dead Sea; Great Salt Lake) 33 ARCHAEAN 34 EUBACTERIA • Some may cause DISEASE • Found in ALL HABITATS except harsh ones • Important decomposers for environment • Commercially important in making cottage cheese, yogurt, buttermilk, etc. 35 Live in the intestines of animals 36 Domain Eukarya is Divided into Kingdoms •Protista (protozoans, algae…) •Fungi (mushrooms, yeasts …) •Plantae (multicellular plants) •Animalia (multicellular animals) 37 •Most are unicellular •Some are multicellular •Some are Protista autotrophic, while others are heterotrophic Mostly Aquatic • 38 Fungi • Multicellular, except yeast • Absorptive • heterotrophs (digest food outside their body & then absorb it) Cell walls made of chitin 39 Plantae •Multicellular •Autotrophic •Absorb sunlight to make glucose – Photosynthesis Cell walls made of cellulose • 40 • Multicellular • Ingestive • Animalia heterotrophs (consume food & digest it inside their bodies) Feed on plants or animals 41 42 Classification is Fun! 43