CLASSIFICATIONChapter 18

CLASSIFICATIONChapter 18

Reference Text:Modern BiologyChapter 18 – Section 1Pgs. 336 - 341

BIG IDEA

• All Organisms on earthare said to have descended from an ancient common ancestor.

WHAT THINGS DO WE CLASSIFY?WHY DO WE CLASSIFY THEM?

HISTORY OF TAXONOMY

Every Year, thousands of new species are discovered.

To study so many life-forms, biologists organize or classify them

into numerous groups based on similar characteristics (structures).

HISTORY OF TAXONOMY

Biological Classification: to group things according to similar/different structures that they share.Classification is very useful in Biology…

• Indicates relationships between species

• Accurately & uniformly names organisms; star fish and jelly fish aren't’ really fish

WHAT IS CLASSIFICATION?

TAXONOMY:The branch of biology that classifies organisms according to

their characteristics andevolutionary history

TAXONOMISTS:

• scientists that identify & name organisms.

• named organisms in a way that reflects their classification.

• use the same language (Latin or some Greek) for all names.

EARLY SYSTEMS OF CLASSIFICATION

The first classification system was developed 2000 years ago by Greek Philosopher, Aristotle.

• He was the first taxonomist.•He simply divided organisms into plants & animals

•He then subdivided them by their habitat:

•land, sea, or air dwellers•Plants, by stem structure

EARLY SYSTEMS OF CLASSIFICATION

EARLY SYSTEMS OF CLASSIFICATION

As modern science developed and more & more organisms began to be discovered, Biologists realized Aristotle’s system was no longer adequate for naming & organizing all life on earth. Sea”horse

”??

EARLY SYSTEMS OF CLASSIFICATION

European bee: Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis glabris utrinque margine ciliatis.

In response to the need for better organization, an 18th century Swedish botanist named Carolus Linnaeus offered a solution to the confusion of classifying and naming organisms.

• Created a hierarchical system for classifying organisms

• Developed naming system still used today

Linnaeus’s SystemCarolus Linnaeus

1707 – 1778

The “Father of Taxonomy”

Linnaeus classified organisms into nestedLevels of Classification based on similarities

in morphology (form & structure), rather than by location.

For example, although Bats can fly, he classified them as mammals, not birds, because they share common traits with other mammals; they have hair, have live births and nurse their offspring with milk.

Linnaeus’s System

The Linnaeus System of Taxonomy uses a hierarchical system for classifying organisms from broadest to most

specific.

The Seven Levels of Classification!KingdomPhylum ClassOrderFamilyGenusSpecies

BROADEST TAXON

MOST SPECIFIC

Linnaeus’s System

Each category or level is called a taxa, hence the

name

taxonomy!

Levels of Classification!

Linnaeus’s System

The Nested Nature of Biological Classification

KeepPlatesCleanOrFamilyGetsSick

Levels of Classification

Taxonomic Group: tiger grey wolfKingdom: Animal Animal Phylum: ChordatesChordates Class: Mammals Mammals Order: Carnivores Carnivores Family: Felines Canines Genus: Panthera Canis Species: tigris lupus

Taxonomic Classification

Name: Genus & species

Which two animals would be more closely related, two from the same phylum or two from the same genus?

THINK ABOUT IT

Linnaeus also developed the

modern system of naming organisms

known as:

Binomialnomenclature

Linnaeus’s System

Why? Common names can vary!What animal is this?

______________ ______________ ______________ ______________ . . . are all names for the same animal

mountain lion

puma

catamou

cougar

BINOMIAL NOMENCLATURE

Also, some early scientific names were often long and difficult to remember…

The European bee, for example, carried the name Apis pubescens, thorace subgriseo, abdomine fusco, pedibus posticis glabris utrinque margine ciliatis.

BINOMIAL NOMENCLATURE

Binomial nomenclature is a two-part naming system that identifies a species with 2 names: Uses Genus & species Either Latin or Greek Italicized in print Capitalize Genus, but

NOT species Underline when writing American

Robin

Turdus migratorius

BINOMIAL NOMENCLATURE

Binomial Nomenclature

copyright cmassengale 30

Which TWO are more closely related?