1 Classification copyright cmassengale Systematics is a field of biology dedicated to the evolutionary history of life on earth Diversity of organisms Evolutionary relationships Biodiversity The variety of organisms The ecosystems they form 3 There are 13 billion known species of organisms There are 13 billion known species of organisms This is only 5% of all organisms that ever lived!!!!! This is only 5% of all organisms that ever lived!!!!! New organisms are still being found and identified New organisms are still being found and identified Species of Organisms copyright cmassengale 4 What is Classification? Classification is the arrangement of organisms into orderly groups based on their similarities Classification is also known as taxonomy Classification is also known as taxonomy ( Naming, Describing,Classifying) Taxonomists are scientists that identify & name organisms copyright cmassengale Linnean Systematics A natural system of classification reflecting the evolutionary history of organism Naming and identifying organisms began with the Greeks and Romans In the Middle Ages, organisms were described using long Latin descriptions copyright cmassengale5 6 Benefits of Classifying Accurately & uniformly names organisms Accurately & uniformly names organisms Prevents misnomers such as starfish & jellyfish that aren't really fish Prevents misnomers such as starfish & jellyfish that aren't really fish Uses same language (Latin or some Greek) for all names Uses same language (Latin or some Greek) for all names Seahorse?? copyright cmassengale 7 Confusion in Using Different Languages for Names copyright cmassengale 8 Latin Names are Understood by all Taxonomists copyright cmassengale 9 Early Taxonomists 2000 years ago, Aristotle was the first taxonomist 2000 years ago, Aristotle was the first taxonomist Aristotle divided organisms into plants & animals Aristotle divided organisms into plants & animals He subdivided them by their habitat ---land, sea, or air dwellers He subdivided them by their habitat ---land, sea, or air dwellers copyright cmassengale 10 Early Taxonomists John Ray, a botanist, argued that each organism should have a set name John Ray, a botanist, argued that each organism should have a set name His names were very long descriptions telling everything about the plant His names were very long descriptions telling everything about the plant copyright cmassengale 11 Carolus Linnaeus 1707 th century taxonomist Classified organisms by their structure Developed naming system still used today copyright cmassengale 12 Carolus Linnaeus Called the Father of Taxonomy Called the Father of Taxonomy Developed the modern system of naming known as binomial nomenclature Developed the modern system of naming known as binomial nomenclature Two-word name (Genus & species) Two-word name (Genus & species) copyright cmassengale 13 Standardized Naming Rules Binomial nomenclature used Latin or Greek Italicized in print Capitalize genus, but NOT species Underline when writing The genus can be abbreviated when used with specific epithet if full name was given before Turdus migratorius T. migratorius American Robin copyright cmassengale Binomial nomenclature Genus + specific epithet examples: Homo sapiens Quercus alba Purpose is to facilitate international science 15 Binomial Nomenclature Which TWO are more closely related? copyright cmassengale 16 Rules for Naming Organisms The International Code for Binomial Nomenclature contains the rules for naming organisms The International Code for Binomial Nomenclature contains the rules for naming organisms All names must be approved by International Naming Congresses (ex: International Zoological Congress) All names must be approved by International Naming Congresses (ex: International Zoological Congress) prevents duplicated names prevents duplicated names copyright cmassengale 17 Classification Groups Taxon ( taxa-plural) is a category into which related organisms are placed Taxon ( taxa-plural) is a category into which related organisms are placed There is a hierarchy of groups (taxa) from broadest to most specific There is a hierarchy of groups (taxa) from broadest to most specific Domain, Kingdom, Phylum, Class, Order, Family, Genus, species Domain, Kingdom, Phylum, Class, Order, Family, Genus, species copyright cmassengale 18 Hierarchy-Taxonomic Groups Domain Kingdom Phylum (Division used for plants) Class Order Family Genus Species BROADEST TAXON- most inclusive Most Specific copyright cmassengale 19 Did King Phillip Come Over For Gooseberry Soup! copyright cmassengale Taxonomic Categories 21copyright cmassengale Six Kingdoms 23 Broadest, most inclusive taxon Broadest, most inclusive taxon Three domains Three domains Archaea and Eubacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles) Archaea and Eubacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles) Eukarya are more complex and have a nucleus and membrane- bound organelles Eukarya are more complex and have a nucleus and membrane- bound organelles Domains copyright cmassengale 24 ARCHAEA Probably the 1 st cells to evolve Live in HARSH environments Found in: Methanogens: Sewage Treatment Plants or anaerobic swamps Thermophiles: Thermal or Volcanic Vents Thermoacidophiles: Hot Springs or Geysers that are acid Halophiles: Very salty water (Dead Sea; Great Salt Lake) copyright cmassengale 25 ARCHAEAN copyright cmassengale 26 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. copyright cmassengale 27 Live in the intestines of animals copyright cmassengale 28 Domain Eukarya is Divided into Kingdoms Protista (protozoans, algae) Protista (protozoans, algae) Fungi (mushrooms, yeasts ) Fungi (mushrooms, yeasts ) Plantae (multicellular plants) Plantae (multicellular plants) Animalia (multicellular animals) Animalia (multicellular animals) copyright cmassengale 29 Protista Most are unicellular Most are unicellular Some are multicellular Some are multicellular Some are autotrophic, while others are heterotrophic Some are autotrophic, while others are heterotrophic Aquatic Aquatic copyright cmassengale 30 Fungi Multicellular, except yeast Multicellular, except yeast Absorptive heterotrophs (digest food outside their body & then absorb it) Absorptive heterotrophs (digest food outside their body & then absorb it) Cell walls made of chitin Cell walls made of chitin copyright cmassengale 31 Plantae Multicellular Multicellular Autotrophic Autotrophic Absorb sunlight to make glucose Photosynthesis Absorb sunlight to make glucose Photosynthesis Cell walls made of cellulose Cell walls made of cellulose copyright cmassengale 32 Animalia Multicellular Multicellular Ingestive heterotrophs (consume food & digest it inside their bodies) Ingestive heterotrophs (consume food & digest it inside their bodies) Feed on plants or animals Feed on plants or animals copyright cmassengale 33copyright cmassengale 34 Taxons Most genera contain a number of similar species Most genera contain a number of similar species The genus Homo is an exception (only contains modern humans) The genus Homo is an exception (only contains modern humans) evolutionary relationships Classification is based on evolutionary relationships copyright cmassengale 35copyright cmassengale 36 Basis for Modern Taxonomy Homologous structures (same structure, different function) Homologous structures (same structure, different function) Similar embryo development Similar embryo development Molecular Similarity in DNA, RNA, or amino acid sequence of Proteins Molecular Similarity in DNA, RNA, or amino acid sequence of Proteins copyright cmassengale 37 Homologous Structures (BONES in the FORELIMBS) shows Similarities in mammals. copyright cmassengale 38 Similarities in Vertebrate Embryos copyright cmassengale Phylogenetic Trees Classification reflects phylogeny: one goal of systematics is to create phylogenetic trees Phylogeny is the evolutionary history of a group of organisms A phylogenetic tree indicates common ancestors and lines of descent or lineages A primative character is a trait that is present in a common ancestor and all members of a group A derived character is present only in a specific line of descent Different linages diverging from a common ancestor have ancestral characteristics-traits shared by ancestor and the species in its lines of descent When we say that 2 species are related we mean that they have a common ancestor copyright cmassengale39 Cladistic Phylogenetic trees Cladistics analyzes primative and derived characteristics and constructs cladograms on the basis of shared derived characteristics copyright cmassengale40 41 Cladogram Diagram showing how organisms are related based on shared, derived characteristics such as feathers, hair, or scales Traces evolutionary history copyright cmassengale 42 Primate Cladogram copyright cmassengale 43 Dichotomous Keying Used to identify organisms Used to identify organisms Characteristics given in pairs Characteristics given in pairs Read both characteristics and either go to another set of characteristics OR identify the organism Read both characteristics and either go to another set of characteristics OR identify the organism copyright cmassengale 44 Example of Dichotomous Key 1a Tentacles present Go to 2 1b Tentacles absent Go to 3 2a Eight Tentacles Octopus 2b More than 8 tentacles 3 3a Tentacles hang down go to 4 3b Tentacles uprightSea Anemone 4a Balloon-shaped bodyJellyfish 4b Body NOT balloon-shaped - 5 copyright cmassengale 45copyright cmassengale