Classification

ClassificationChapter 18

The science of naming and classifying living things.

Taxonomy

Pre-1700 common names were used to identify organisms.◦ Long◦ Variable

Common Names

Grouped all organisms into two groups:◦ Plants and animals◦ Not everyone fit

Aristotle

1700’s – Carolus Linnaeus◦ Devised a two-name system of naming

Genus, species

Binomial Nomenclature

Felis domesticus

Canis familiaris

Canis lupus

Homo sapiens

Linnaeus created 7 groups from the largest Kingdom to the smallest Species.

Classification Groups

Section 18-1

Flowchart

Linnaeus’s System of Classification

Kingdom

Phylum

Class

Order

Family

Genus

Species

Grizzly bearBlack bear Giant panda

Red fox Abert squirr

el

Coral snake

Sea star

KINGDOM Animalia

PHYLUM Chordata

CLASS Mammalia

ORDER Carnivora

FAMILY Ursidae

GENUS Ursus

SPECIES Ursus arctos

Section 18-1

Figure 18-5 Classification of Ursus arctos

1700’s – plant & animal Late 1800’s – protist, plant, animal 1950’s – monera, protist, fungi, plant,

animal 1990’s – eubacteria, archaebacteria, protist,

fungi, plant, animal Today - More divisions:

◦ 3 Domains are divided into 6 kingdoms

Kingdoms

DOMAIN

KINGDOM

CELL TYPE

CELL STRUCTURE

S

NUMBER OF CELLS

MODE OF NUTRITION

EXAMPLES

Bacteria

Eubacteria

ProkaryoteCell walls with peptidoglycan

Unicellular

Autotroph or heterotrophStreptococcus, Escherichia coli

Archaea

Archaebacteria

ProkaryoteCell walls without peptidoglycan

Unicellular

Autotroph or heterotrophMethanogens, halophiles

Protista

EukaryoteCell walls of cellulose in some; some have chloroplasts

Most unicellular; some colonial; some multicellularAutotroph or heterotrophAmoeba, Paramecium, slime molds, giant kelp

Fungi

EukaryoteCell walls of chitin

Most multicellular; some unicellular

Heterotroph

Mushrooms, yeasts

Plantae

EukaryoteCell walls of cellulose; chloroplasts

Multicellular

Autotroph

Mosses, ferns, flowering plants

Animalia

EukaryoteNo cell walls or chloroplasts

Multicellular

Heterotroph

sponges, worms, fishes, mammals

Eukarya

Classification of Living Things

Section 18-3

Figure 18-12 Key Characteristics of Kingdoms and Domains

Based on evolutionary relationships, not just visual similarities.◦ Cladograms (phylogenic trees)

Modern Classification System

CLADOGRAM

Appendages Conical Shells

Crab Barnacle Limpet Crab Barnacle Limpet

Crustaceans Gastropod

Molted exoskeletonSegmentation

Tiny free-swimming larva

Section 18-2

Traditional Classification Versus Cladogram

CLASSIFICATION BASED ON VISIBLE

SIMILARITIES

CLASSIFICATION BASED ON VISIBLE

SIMILARITIES

CLADOGRAM

Appendages Conical Shells

Crab Barnacle Limpet Crab Barnacle Limpet

Crustaceans Gastropod

Molted exoskeletonSegmentation

Tiny free-swimming larva

Section 18-2

Traditional Classification Versus Cladogram