Chapter 18 Classification

What is Classification? Classification is the grouping of objects based on similarities ◦ Classifying Biology and Chemistry as Science is a type of classification ◦ We classify organisms to help name them and to create order Taxonomy is the branch of biology that groups and names organisms

How did taxonomy begin? What do you call this animal? ◦ Mountain lion, cougar, puma, panther

What is Classification? Binomial nomenclature gives each species a two-part scientific name ◦ The first word is the genus, the second is the species ◦ Grizzly bear: Ursus arctos ◦ Polar bear: Ursus maritimus ◦ Giant panda: Alluropoda melanoleuca ◦ Most are Latin ◦ Developed by Carolus Linnaeus in late 1700s

What is Classification? Linnaeus’s classification included a hierarchal system with 7 levels Taxon: grouping (categories) of organisms, plural is taxa ◦ Kingdom: taxon of similar phyla ◦ Phylum: taxon of similar classes ◦ Class: taxon of similar orders ◦ Order: taxon of similar families ◦ Family: taxon of similar genera; example cat family is Felidae ◦ Genus: taxon of similar species ◦ Species: specifies organism; Homo sapiens

Taxonomy

Taxonomy

Classification How do we determine how to group organisms together? ◦ What similarities/differences are most important? ◦ How do you classify a dolphin? Is it more similar to a fish or a cat? Darwin’s ideas of evolution led to the study of phylogeny (evolutionary relationships among organisms)

Classificantion Grouping organisms based on their evolutionary history is called evolutionary classification ◦ Species with the same genus are more closely related than another genus ◦ Same genus all share a common ancestor ◦ The farther you go up in taxa, the further back the common ancestor was Cladograms show relationships of evolutionary classification

Cladograms Wg Wg

Cladograms

Dichotomous Key A dichotomous key is multiple sets of paired statements used to identify organisms nCentral/walk/walk4.html nCentral/walk/walk4.html

3 Domains Bacteria, Archaea, and Eukarya Bacteria and Archaea are prokaryotes. ◦ Domain Bacteria has Kingdom Eubacteria. “normal” bacteria ◦ Domain Archaea has Kingdom Archebacteria. “weird” bacteria

Eukarya Kingdom Protista ◦ Most are unicellular ◦ Live in moist environments ◦ Diverse in ways they obtain nutrition. Ex. amoebahttp:// Kingdom Fungi ◦ Heterotrophic decomposers ◦ Cell walls of chitin, ex. mushroom; picturespictures

Eukarya Kingdom Plantae ◦ Autotrophic, multicellular, have tissues ◦ Cell walls of cellulose ◦ Vascular plants – have vessels that transport water and sugars (ferns, conifers, flowering plants)  Xylem – tissue that moves water  Phloem – tissue that moves sugars ◦ Nonvascular plants do not have these vessels., ex. mosses Kingdom Animalia – multicellular heterotrophs. Do NOT have cell walls

Classification of Living Things

Domain, Kingdom, Phylum… DidDomain KingKingdom PhilipPhylum CrossClass OverOrder ForFamily GoodGenus SoupSpecies