Unit 11: Classification

Ch. 3 Classification

Taxonomy = branch of biology that deals w/ naming & classifying organisms.

Why Things Are Classified?

• What does it mean to classify?–to group things based on similarities

• Examples of classifying in everyday life…

• Why are organisms classified?–easier to find

–show shared traits

–show relationships among living & extinct species

Why Things Are Classified?• How are organisms classified?

– very broad characteristics very specific• based on evolutionary relationships

– A group of organisms is called a taxon.

• Tools used to classify organisms…– dichotomous keys

• 1st classification system–Aristotle

• 2 groups–1. plants

» by type of stem

–2. animals» by environment

Early Classification

According to Aristotle, which of these 3 animals would be classified more closely?

• Carolus Linnaeus “Father of Modern Taxonomy”–2 main groups = kingdoms

• plants

• animals

–Also used:• genus

–similar species

• species–organisms w/ similar traits

Beginning of Modern Classification

• Linnaeus 1st to consistently use binomial nomenclature

– 2 name system• written: Genus species or Genus species

– Genus = 1st name, capitalized– species = 2nd name, lower case & descriptive

• Ex. Common name Genus & species– Humans Homo sapiens– White Oak tree Quercus alba– Red Oak tree Quercus rubra– Bottlenose dolphin Tursiops truncatus

Beginning of Modern Classification

• Why don’t we use common names?

1. two organisms can have same common name, but not sci. name

2. scientific names rarely change

3. scientific names are written in same language around the world

Beginning of Modern Classification

• current system reflects relationships– based on evolutionary ancestry– can change in response to new data

• According to the phylogenetic tree on the right who are humans most closely related to?

How Scientists Classify Today

• slightly different classification systems– 5 Kingdom system

• Monera, Protista, Fungi, Plantae, Animalia

– 6 Kingdom system• Monera split into Archaea (Archaebacteria) & (Eu)bacteria…

other 4 kindgoms remain same

– 3 Domain system• Archaea, (Eu)bacteria, Eukaryota (Eukarya)

– 4 kingdoms (Protista, Fungi, Plantae, Animalia) grouped in Eukaryota

How Scientists Classify Today

Where would Domain belong in this diagram?

How Scientists Classify Today• When using the 5 or 6

Kingdom system– Kingdom

• largest, most inclusive

– species• smallest, least inclusive

How Scientists Classify Today• When using the 3

Domain system– domain

• largest, most inclusive

– species• smallest, least inclusive

DomainEukaryota

Domain

• What is a species?– Group of

organisms capable of mating with one another in nature to produce fertile offspring

How Scientists Classify Today

• Did Domain• King Kingdom• Phillip Phylum• Come Class• Over Order• For Family• Good Genus• Spaghetti? species

How Scientists Classify Today• A trick to help you remember all the major

classification groups…

King Phillip

This is really

GOOD!!! I’m so glad I

came!

• What is the relationship among the levels?– more closely

related share more levels

– from Domain down, each level has a new set of criteria that must be shared

DOMAIN Eukaryota

How Scientists Classify Today

Once an organism shares a more specific taxon (lower group) it MUST share the more unifying

taxa (higher groups)

How many levels of classification do we share with dolphins?

Domain: ArchaeaKingdom: Monera• prokaryotic

• unicelluar

• feeding– heterotrophic or autotrophic

• other characteristics– older, less complex bacteria– live in extreme environments

• examples– bacteria:

• in salt lakes• at hydrothermal vents

Staphylococcus

cyanobacteria

Domain: EubacteriaKingdom: Monera• prokaryotic

• unicelluar• feeding

– heterotrophic or autotrophic

• other characteristics– modern, more complex bacteria

• evolved from Archaea

– most common & very diverse– free-living or pathogenic

• examples– Staphylococcus– E. coli– cyanobacteria

Domain: Eukaryota• All are eukaryotic

• 4 of the 5 kingdoms– 1. Protista– 2. Fungi– 3. Plantae– 4. Animalia

Domain: Eukaryota1. Kingdom: Protista

• eukaryotic• mostly unicelluar• feeding

– heterotrophic or autotrophic

• other characteristics– can be plant-like, animal-

like, or fungus-like

• examples– Amoeba– Paramecium– Euglena– algae

Amoeba

Paramecium

Euglena

• eukaryotic• multicelluar***• feeding

– heterotrophic• digest food outside & absorb nutrients

• other characteristics– cell walls made of chitin– decomposers & parasites

• examples– mushrooms– molds– yeast (*** unicellular)

Domain: Eukaryota2. Kingdom: Fungi

• eukaryotic

• multicelluar

• feeding– autotrophic

• photosynthesis

• other characteristics– cell walls made of cellulose

– produce oxygen

• examples– mosses

– ferns

– grasses

– shrubs

– trees

Domain: Eukaryota3. Kingdom: Plantae

• eukaryotic• multicelluar• feeding

– heterotrophic

• other characteristics– no cell wall

Domain: Eukaryota4. Kingdom: Animalia

• examples– invertebrates

• insects• worms• sponges• corals

– vertebrates• fish• birds• amphibians• reptiles• mammals

Links• http://www.brainpop.com/science/diversityoflife/classification/preview.weml• http://anthro.palomar.edu/animal/default.htm• http://www.ruf.rice.edu/~bioslabs/studies/invertebrates/kingdoms.html• http://www.nclark.net/Classification