Classification/Taxonomy

Chapter 18

Why Classify?To study the diversity of life, biologists use a

classification system to name organisms &

group them in a logical manner.

TaxonomyDefined:

Discipline of classifying organisms and assigning each

organism a universally accepted name.

In other words, naming things.

Why common names don’t workCommon names vary among languages and regions.

Example:

United Kingdom – Buzzard refers to a hawk

United States – Buzzard refers to a vulture

Red-tailed Hawk Honey Buzzard Turkey Vulture

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Aristotle 384 BC Classified organisms

as either plants or animals

Carolus Linnaeus(1707 – 1778)

Created the system of naming we use today.

In taxonomy, a group or level of organization is called a taxonomic category or taxon.

Binomial Nomenclature“Bi” means 2“nomial” means number“Nomen” means name“Clature” means the system of

Defined:

In binomial nomenclature, each species is assigned a two-part

scientific name.

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Binomial Nomenclature  Carolus Linnaeus In binomial nomenclature, each species

is assigned a two-part scientific name. The scientific name is always written in italics

or underlined. The first word (the genus) is capitalized The second word (the species) is lowercased.EX- Genus species or Genus speciesHumans- Homo sapien

Example of Binomial NomenclaturePolar Bear is Ursus maritimus Ursus: genus

Ursus contains 5 other kinds of bears

maritimus: species The Latin word, maritimus, refers to the sea.

Polar bears often live on pack ice that floats in the sea.

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Linnaeus's System of Classification

A group or level of organization is called a taxonomic category, or taxon

Linnaeus had 7-Kingdom “King Phylum PhillipClass CameOrder OverFamily ForGenus Great Species Spaghetti”

Definitions to knowGenus: is a group of closely related species

Species: Group of similar organisms that can breed and produce fertile offspring

Family: Group of genera that share many characteristics

Order: Group of similar families

Class: Group of similar orders

Phylum: Group of closely related classes

Kingdom: Largest taxonomic group, consisting of closely related phyla.

Here We Go…Polar Bear

Kingdom: AnimaliaPhylum: ChordataClass: MammaliaOrder: CarnivoraFamily: UrsidaeGenus: Ursus

Species: maritimus

What do these mean?...lets see

What they mean

Kingdom: Animalia (there are 6 kingdoms)Phylum: Chordata (vertebrates)Class: Mammalia (warm-blooded, hair, & milk)Order: Carnivora (meat-eating animals)Family: Ursidae (larger category of bears)Genus: Ursus (kind of bear)Species: maritimus (lives in marine environment)

*Do NOT have to write*

How to remember:King Phillip Came Over For Green Salad

Kingdom Phylum Class Order Family Genus Species

Rules of the GameUniqueness: Every name has to be unique.

Universality: Zoologists have adopted, by international agreement, a single language to be used on a worldwide basis. All animals are given a generic (common name) and specific name in Latin (scientific name).

These names are in italics or are underlined (i.e. Homo sapiens).

Visuals

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Modern Three-Domain System As scientists further analyzed cell structure and

DNA , a broader category was added- The domain is the most inclusive taxonomic

category; larger than a kingdom    The three domains are:

Bacteria : kingdom Eubacteria

Archaea,: kingdom Archaebacteria;

Eukarya :Kingdom protists, fungi, plants, and animals.

KingdomsEubacteriaArchaebacteriaProtistaPlantaeFungiAnimalia

DOMAIN EUKARYA

DOMAIN ARCHAEA

DOMAIN BACTERIA

Section 18-3

Cladogram of Six Kingdoms and Three Domains

Go to Section:

Modern 6 Kingdom System

Recently, as evidence about microorganisms continue to accumulate, biologists came to realize that the Kingdom Monera were composed of 2 distinct groups.

The 6-Kingdom system of classification includes kingdoms:

1. Eubacteria 2. Archaebacteria 3. Protista4. Fungi 5. Plantae 6. Animalia

6 KingdomsEubacteria Archaebacteria Protista Fungi Plantae Animalia

E. ecoli Paramecium Fern frodH. coccinea Homo sapiensPyrococcus furiosus

ProkaryoteProkaryote Eukaryote Eukaryote Eukaryote Eukaryote

Autotroph orheterotroph

Autotroph orheterotroph

Autotroph/heterotroph

Heterotroph HeterotrophAutotroph

Most common bacteria

Live in very hot places

Includes AlgaeDon’t

belong in other euk

Cell walls &

Chloroplasts

Release enzymes to digest

food

No cell wall

No chloroplasts

Multicellular

“Ancient Bacteria”

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Checkpoint Questions:1.  How are living things organized for

study?2. Describe the system for naming species

that Linnaeus developed. 3. What are the seven taxonomic categories

of Linnaeus’s classification system? 4. Why do scientists avoid using common

names when discussing organisms? 5.  What is significant about members of

the same species?