Classification of Organisms

Dichotomous Key A dichotomous key is a method for determining the identity of something by going through a series of choices that leads the user to the correct name of the item At each step of the process of using the key, the user is given two choices; each alternative leads to another question until the item is identified. (It's like playing 20 questions.)

Tree Style Dichotomous Key This is the style we will be making

Dichotomous Key for Candy Note: “scientific names” are made up here.  This style is common in identification books.  Use this style in the homework

A Dichotomous Key for Sharks Note: real scientific names here

Binomial nomenclature Over 2,000 years ago Aristotle categorized living things by their appearances into plants and animals He came up with a two-part name for each organism. This was the first Binomial nomenclature: a classification system in which each species are assigned a two-part scientific name

Linnaeus In the 1750’s Carolus Linnaeus expanded on the binomial nomenclature idea and devised a systematic method in which each species had its own unique binomial nomenclature Two-part name

Linnaeus knew that the names needed to be universal He used Latin because it is a dead language. This means that it is not used as ordinary spoken languages for everyday communication and therefore does not change. Linnaean Classification

Who invented the first classification system based on a two part name? Aristotle What is this two-part style classification system called? Binomial nomenclature Who refined this by creating a systematic method in which each species had its own unique binomial nomenclature? Linnaeus

Scientific Names This is the system we use today. The first part of the name is the genus to which it belongs; it always starts with a capital letter The second part of the name is a description. Traditionally, a physical description, where it is from or first found, or named after someone; it is written in all lower case letters The whole scientific name is always italicized or underlined When hand written

Example: Genussecond term Tachyglossus aculeatus Sometimes you will see this abbreviated. Example: T. aculeatus Still italicized! Scientific Names together uniquely identify each species Common name: Short-beaked echidna

What is the first part of the scientific name? the genus to which it belongs The scientific name of this animal is written incorrectly. How would you make it correct?puma concolor Common names: mountain lion, puma, panther, painter, mountain cat, or catamount Puma concolor or Puma concolor When hand written

Taxa: Rank-Based Classifying Linnaeus expanded on this grouping system to include a hierarchy of more distantly related organisms until all organisms were encompasses

Taxa: Rank-Based Classifying Eventually there were seven hierarchical levels to which we call taxa (plural) or taxon (singular) Let’s follow an example through the various levels…

Species Genus Family Order Class Phylum Kingdom Procyon lotor Common Name: Raccoon

Species Genus Family Order Class Phylum Kingdom Procyon lotor Common Name: Raccoon Procyon Crab-eating raccoon

Species Genus Family Order Class Phylum Kingdom Procyon lotor Common Name: Raccoon Procyon Procyonidae Nasuella Olingos ChapalmalaniaBassariscusNasua Raccoon Kinkajou

Species Genus Family Order Class Phylum Kingdom Procyon lotor Common Name: Raccoon Procyon Procyonidae Carnivora tiger spotted hyena African civet brown bear grey wolf wolverine

Species Genus Family Order Class Phylum Kingdom Procyon lotor Common Name: Raccoon Procyon Procyonidae Carnivora Mammalia Orangutan and Human (babies)

Species Genus Family Order Class Phylum Kingdom Procyon lotor Common Name: Raccoon Procyon Procyonidae Carnivora Mammalia fish amphibians tunicates Chordate reptiles (including birds)

Procyon lotor Common Name: Raccoon Procyon Procyonidae Carnivora Mammalia Chordate Animalia Species Genus Family Order Class Phylum Kingdom

Memorize this list!!!!! Kings play chess on fat guys stomachs. KingsKingdom PlayPhylum ChessClass OnOnOrder FineFamily GlassGenus SurfacesSpecies

Kentucky Plants Can Originate From Good Soil KentuckyKingdom PlantsPhylum CanClass OriginateOrder FromFamily GoodGenus SoilSpecies

Taxonomy Describes Evolutionary History As new technologies (such as DNA mapping) are developed these groups are refined Many biologists now use a three domain addition based on DNA and molecular evidence. 1.Bacteria 2.Archaea 3.Eukarya You need to know these!

What domain are humans in? Eukarya What are the other two domains? Bacteria & Archaea

Phylogeny Phylogeny: the study of how living and extinct organism are related to each other Clade: A group of species that includes their single common ancestor and all descendents of that ancestor. Scientists use Cladistics to build phylogenies

Examples of Cladograms Don’t let this trip you up! This is only a different style!

Two different clades because of which common ancestor is included Common ancestor for each clade

Common ancestor for clade

Birds Crocodiles Lizards & Snakes Turtles Mammals Amphibians Fish “Reptiles” are not a clade unless we include birds