ClassificationChapter 17

His

tory

of

Cla

ssifi

cati

on

Early Systems of ClassificationClassification: grouping

of objects or organisms

based on a set of criteria

oBiologists use a system

of classification to organize information

about the diversity of

living things.oAristotle and Linnaeus

Ari

stotl

e’s

Sys

tem

o394 – 322 BCoDeveloped 1st widely

accepted system of biological classification

oClassified organisms

as either animals or plants

Ari

stotl

e’s

Sys

tem

oAnimals were classified

according to the presence or

absence of “red blood.”

oAnimals were further grouped

according to their habitats

and morphology.oPlants were classified by

average size and structure as

trees, shrubs, or herbs.

Proble

ms

wit

h

Ari

stotl

e’s

Sys

tem

oBased upon the idea

that species are distinct and unchanging. Doesn’t

account for evolution.oMany organisms didn’t

fit into a category.o Example: Birds who

don’t fly.

Linnaeus’

Sys

tem

o1707 – 1778oFirst formal system of

taxonomyoTaxonomy: discipline

of biology primarily concerned with identifying, naming, and classifying species

based on natural relationships

Linnaeus’

Sys

tem

oBinomial Nomenclature: method

of naming organisms that

uses a TWO PART name

for each speciesoPart One: Genus name

oPart Two: Specific epithet

(AKA specific name)NOTE: Latin is the basis for

binomial nomenclature

because it is an unchanging

language.

Sci

enti

fic

Nam

es

vs.

Com

mon N

am

es

oScientific names are

used for species because:o Common names vary

from person to persono Common names can be

misleadingo Example: Starfish are

NOT fish. Horned owls do

NOT have horns.

Sci

enti

fic

Nam

e

Rule

s

o The first letter of the genus name

always is capitalized, but the rest

of the genus name and all letters

of the specific epithet are

lowercase.o If a scientific name is written in a

printed book or magazine, it

should be italicized.oWhen a scientific name is written

by hand, both parts of the name

should be underlined.

o After the scientific name has been

written completely, the genus

name will be abbreviated to the

first letter in later appearances

(e.g., C. cardinalis).

Taxo

nom

ic

Cate

gori

es

oThe taxonomic categories

used by scientists are

part of a nested-hierarchal system.

oEach category is contained within another,

and they are arranged

from broadest to most

specific.

Speci

es

and

Genus

oTaxa: named group of

organismsoA genus is a group of

species that are closely

related and share a common ancestor.

Genus E

xam

ple

Ursus americanus

Ursus

thibetanus

Melursus ursinus

SAME GENUS

Different GENUS

Fam

ily

oA family is the next higher taxon, consisting of similar,

related genera.o Example: Ursidaeo Contains all bears

( Both Ursus and Melursus)o Contains NINE different

species of bears

Hig

her

Taxa

oAn order contains related

families.oA class contains related

orders.oA phylum or division

contains related classes.

oThe taxon of related phyla

or divisions is a kingdom.

oThe domain is the broadest of all the taxa

and contains one or more

kingdoms.

Cla

ssifi

cati

on

Sum

mary

oDomainoKingdomoPhylumoClassoOrderoFamilyoGenusoSpecies

Dom

ain

s and

Kin

gdom

s

oThe most widely used

biological classification

system has six kingdoms and three

domains.oThe three domains

are Bacteria, Archaea,

and Eukarya.oThe six kingdoms are

Bacteria, Archaea, Protists, Fungi, Plantae,

and Animalia.

Dom

ain

Bacte

riaoEubacteria are

prokaryotes

whose cell walls

contain

peptidoglycan.

oEubacteria are

a diverse

group that can

survive in

many different

environments.

Dom

ain

Arc

haea

oArchaea are thought to

be more ancient than

bacteria and yet more

closely related to our

eukaryote ancestors.oArchaea are diverse in

shape and nutrition requirements.oThey are called

extremophiles because

they can live in extreme environments.

Dom

ain

Euka

rya

oThey are called extremophiles because

they can live in extreme

environments.oDomain Eukarya contains Kingdom Protista, Kingdom Fungi,

Kingdom Plantae, and

Kingdom Animalia.

Kin

gdom

Protista

oProtists are

eukaryotic

organisms that

can be

unicellular,

colonial, or

multicellular.

oProtists are

classified into

three different

groups: plant-

like, animal-like,

and fungus-like.

Kin

gdom

Fungi

oA fungus is a

unicellular or

multicellular

eukaryote that

absorbs

nutrients from

organic

materials in its

environment

oMembers are

heterotrophic,

lack motility,

and have cell

walls.

Kin

gdom

Pla

nta

eoMembers of

Kingdom Plantae

form the base of

all terrestrial

habitats.

oAll plants are

multicellular and

have cell walls

composed of

cellulose.

oMost plants are

autotrophs, but

some are

heterotrophic.

Kin

gdom

Anim

alia

oAll animals are

heterotrophic,

multicellular

eukaryotes.

oAnimal organs

often are

organized into

complex organ

systems.

oThey live in the

water, on land,

and in the air.

Kin

gdom

Sum

mary