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

• ________________________-has levels• _______________________--name for each level • Kingdom-

_____________________________________

Heirarchical system

taxon

Largest and most inclusive of categories

B.cont’d

• ____________________-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

Phylum

class

order

family

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

Phylogenycladogram

Derived characters

Phylogeny

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

• 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

EUKARYA

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