Chapter 18

Classification

Why Classify?

In order to name and group organisms in a logical manner

Taxonomy- classifying organisms and assigning each a name

Assigning Scientific Names

Early Efforts- described physical characteristics

Binomial Nomenclature- (Carolus Linnaeus) two word naming system, the genus and species• Always typed in italics

• Underlined when written

Ursus arctos

Ursus maritimus

When written or typed the genus is always capitalized and the species is not

Grizzly bear Black bear Giant panda Red fox Abert squirrel

Coral snake Sea star

KINGDOM Animalia

PHYLUM Chordata

CLASS Mammalia

ORDER Carnivora

FAMILY Ursidae

GENUS Ursus

SPECIES Ursus arctos

Linnaeus’s System (7 levels)

Kingdom Phylum Class Order Family Genus Species

Evolutionary Classification

Phylogeny- study of evolutionary relationships among organisms

Biologists classify organisms by grouping

them according to evolutionary descent, not physical characterists.

Cladograms

Used derived characteristics to show evolutionary relationships among a group of organisms

Similarities in DNA/RNA

Molecular Clock

CLASSIFICATION BASED ON VISIBLE

SIMILARITIESCLADOGRAM

AppendagesConical Shells

Crab Barnacle Limpet Crab Barnacle Limpet

Crustaceans Gastropod

Molted exoskeleton

Segmentation

Tiny free-swimming larva

Kingdoms and Domains

Kingdoms

• Animalia

• Plantae

• Fungi

• Protista

• Archaebacteria

• Eubacteria

Domains

• Eukarya

• Archaea

• Bacteria

Kingdoms and Domains

DOMAIN

KINGDOM

CELL TYPE

CELL STRUCTURES

NUMBER OF CELLS

MODE OF NUTRITION

EXAMPLES

Bacteria

Eubacteria

Prokaryote

Cell walls with peptidoglycan

Unicellular

Autotroph or heterotroph

Streptococcus, Escherichia coli

Archaea

Archaebacteria

Prokaryote

Cell walls without peptidoglycan

Unicellular

Autotroph or heterotroph

Methanogens, halophiles

Protista

Eukaryote

Cell walls of cellulose in some; some have chloroplasts

Most unicellular; some colonial; some multicellular

Autotroph or heterotroph

Amoeba, Paramecium, slime molds, giant kelp

Fungi

Eukaryote

Cell walls of chitin

Most multicellular; some unicellular

Heterotroph

Mushrooms, yeasts

Plantae

Eukaryote

Cell walls of cellulose; chloroplasts

Multicellular

Autotroph

Mosses, ferns, flowering plants

Animalia

Eukaryote

No cell walls or chloroplasts

Multicellular

Heterotroph

Sponges, worms, insects, fishes, mammals

Eukarya

Classification of Living Things

DOMAIN BACTERIA

DOMAIN ARCHAEA

DOMAIN EUKARYA Eubacteria

Archaebacteria

Protista

Plantae

Fungi

Animalia

Kingdoms

3 Domain System

Archaea vs Bacteria

Endosymbiotic Theory

Dichotomus Key

A series of paired statements that describe characteristics of different organisms.