Classification Chapter 18

Why Classify ? To study diversity of life in organized manner. ________________-science where organisms are classified in a universal manner Taxonomy

A. Scientific Names Early efforts described physical characteristics in detail 1)Binomial Nomenclature-developed by Carolus Linnaeus 2 part scientific name 1st word is genus and 2nd ________________- Italicize or underline both words 1st letter of 1st word is capitalized Names often Latin species

B. Linnaeus’s System taxon ________________________-has levels _______________________--name for each level Kingdom-_____________________________________ taxon Heirarchical system Largest and most inclusive of categories

B.cont’d class ____________________-many different organisms that share important characteristics _______________-composed of similar orders _______________-broad group of similar families _______________-genera sharing characteristics-like the Uridae family for bears Genus-closely related species Species-successfully interbreeding family Phylum order

Family Tree of Major Taxa Kingdom Phyla Class Order Family Genus Species

II. Modern Evolutionary Classification __________________-evolutionary relationships between organisms Genus should share common ancestor Derived characteristics can be used to form a ________________-showing evolutionary relationships ______________-characteristics that appear in recent lineage more but not in older members similarities in DNA and RNA can give more conclusive classification cladogram Phylogeny Derived characters

Phylogeny

Tips of branches stand for Tips of branches stand for most recent evolutionary representatives and branches stand for common ancestors-new branch means a new species

Cladogram

III. Kingdoms and Domains A.The Three-Domain System Grouped by molecular analysis More inclusive category

EUKARYA 1) _________-protists,fungi,plants and animals Protists-great variety Most single-celled,but there are multicellular algae Fungi-decomposing heterotrophs Plantae-multicellular,photosynthetic autotrophs Animalia-muticellular and heterotrophic 2) BACTERIA-eubacteria-unicellular and prokaryotic;thick cell walls;free-living or parasitic;diverse 3)_____________unicellular and prokaryotic;live in extreme conditions like hot springs or volcanic vents;can live w/o oxygen;not as thick cell walls ARCHAEBACTERIA-

Kingdoms- Eubacteria and archaebacteria Protista,Fungi,Plantae,Animalia

Classification method A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish. Keys consist of a series of choices that lead the user to the correct name of a given item. "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step.

Dichotomous key