Chapter 17Chapter 17

TaxonomyTaxonomy

History of TaxonomyHistory of Taxonomy Biologists use a classification system to group Biologists use a classification system to group

organisms in part because organisms are organisms in part because organisms are numerousnumerous and and diversediverse..

Taxonomy is the branch of biology that Taxonomy is the branch of biology that namesnames and and groupsgroups organisms according to their organisms according to their characteristicscharacteristics and and evolutionaryevolutionary history. history. It was first proposed by It was first proposed by Aristotle Aristotle in 350 BC.  in 350 BC. 

He only had 2 groups 1) He only had 2 groups 1) Plants Plants & 2& 2)Animals.)Animals.

Who came up with an organized classification Who came up with an organized classification system?system? Carolus Carolus LinnaeusLinnaeus Used an organism’s Used an organism’s morphology (shapes)morphology (shapes)

Levels of ClassificationLevels of Classification Dumb King Phillip Came Over for Grape Dumb King Phillip Came Over for Grape

SodaSodaDomainDomainKingdomKingdomPhylumPhylumClassClassOrderOrderFamily Family GenusGenusSpeciesSpecies

Binomial NomenclatureBinomial Nomenclature

In Linnaeus’s system, the species name In Linnaeus’s system, the species name has has twotwo parts parts

The first part of the name is the The first part of the name is the genusgenusThe second part is the The second part is the speciesspecies identifier identifierThis system of two-part names is known This system of two-part names is known

as as binomialbinomial nomenclature nomenclatureThe genus name is The genus name is capitalizedcapitalizedBoth names are Both names are underlinedunderlined or written in or written in

italicsitalics

To classify organisms, taxonomists To classify organisms, taxonomists consider the consider the phylogenyphylogeny (evolutionary (evolutionary history) of the organismhistory) of the organism

By concentrating on By concentrating on morphologymorphology, , Linnaeus focused on features that are Linnaeus focused on features that are largely influenced by largely influenced by genesgenes and that and that are clues of common ancestry.are clues of common ancestry.

Modern Phylogenic Modern Phylogenic TaxonomyTaxonomy

SystematicsSystematics organizes living things in organizes living things in the based on evolutionthe based on evolution

A A phylogenicphylogenic tree shows the tree shows the evolutionary relationships among evolutionary relationships among organismsorganisms

To develop a phylogenic tree To develop a phylogenic tree taxonomists must considertaxonomists must considerthe the fossilfossil record recordmorphologymorphologyembryological patterns of embryological patterns of developmentdevelopmentchromosomeschromosomes and macromolecules and macromolecules

A A speciesspecies is a group of individuals is a group of individuals agreeing in form, habit, & offspring.  agreeing in form, habit, & offspring.  Ernst May defined a species as a Ernst May defined a species as a group of actually or potentially group of actually or potentially interbreeding natural populations interbreeding natural populations that are reproductively isolated from that are reproductively isolated from other such groups.  Species typically other such groups.  Species typically produce fertile offspring. produce fertile offspring. 

CladisticsCladistics

Cladistics uses certain features of Cladistics uses certain features of organisms, called shared organisms, called shared derivedderived characteristics, to establish characteristics, to establish evolutionaryevolutionary relationships relationships

A derived character is a A derived character is a featurefeature that that evolved evolved onlyonly within the group under within the group under considerationconsideration

Ancestry diagrams made by cladistic Ancestry diagrams made by cladistic analysis are called analysis are called cladogramscladograms

A A cladogramcladogram is is a tree-like a tree-like diagram showing diagram showing evolutionary evolutionary relationshipsrelationships.. Any two branch tips Any two branch tips sharing the same sharing the same immediate node are immediate node are most closely relatedmost closely related

3 Domains3 Domains

Domain Bacteria Domain Bacteria – All eubacteria– All eubacteriaDomain Archaea Domain Archaea – All archaebacteria– All archaebacteriaDomain Eukarya Domain Eukarya – All eukaryotes – – All eukaryotes –

protists, fungi, plants, & animalsprotists, fungi, plants, & animals

Six-Kingdom ClassificationSix-Kingdom ClassificationThe six-kingdom classification The six-kingdom classification

we will study includes we will study includes ArchaebacteriaArchaebacteria, Eubacteria, , Eubacteria, Protista, Protista, FungiFungi, Plantae, and , Plantae, and AnimaliaAnimalia

ArchaebacteriaArchaebacteriaUnicellularUnicellular prokaryotes prokaryotesNo peptidoglycanNo peptidoglycan in cell walls in cell walls Many live in Many live in harshharsh environments (hot environments (hot

springs, salty lakes or anaerobic springs, salty lakes or anaerobic environments)environments)

Believed to be similar to some of the Believed to be similar to some of the firstfirst organisms on Earth. organisms on Earth.

Some are Some are autotrophsautotrophs (make their own (make their own food), and some are food), and some are heterotrophs heterotrophs (do (do not make their own food)not make their own food)

EubacteriaEubacteriaUnicellularUnicellular prokaryotes prokaryotesPeptidoglycanPeptidoglycan in cell walls in cell wallsMost of the bacteria you know Most of the bacteria you know

(good and bad)(good and bad)Most are Most are aerobicaerobic (use O (use O2 2 to to

breathe), but some are breathe), but some are anaerobicanaerobic (do not use O(do not use O2 2 to breathe)to breathe)

Some are Some are autotrophsautotrophs, and some , and some are are heterotrophsheterotrophs

ProtistaProtistaThe The unicellularunicellular eukaryoteseukaryotes

that aren’t Fungi, Plantae, or that aren’t Fungi, Plantae, or AnimaliaAnimalia

They are subdivided as They are subdivided as Fungus-likeFungus-like, Plant-like, or , Plant-like, or Animal-likeAnimal-like

Includes Includes autotrophsautotrophs and and heterotrophsheterotrophs

FungiFungi

EukaryotesEukaryotesUnicellularUnicellular and and

multicellularmulticellularCell walls made of Cell walls made of chitinchitinCANNOT MAKE THEIR CANNOT MAKE THEIR

OWN FOODOWN FOOD

PlantaePlantaeMulticellular Multicellular eukaryoteseukaryotesAll except a few parasitic All except a few parasitic

forms are forms are photosyntheticphotosynthetic – – does that make them does that make them autotrophs or heterotrophs?autotrophs or heterotrophs?

Cell walls made of Cell walls made of cellulosecellulose

AnimaliaAnimaliaEukaryotesEukaryotesMulticellularMulticellularHeterotrophsHeterotrophsMost have Most have symmetricalsymmetrical bodybody organization organization

Dichotomous KeysDichotomous Keys

• A tool to identify organisms is A tool to identify organisms is called a called a dichotomous keydichotomous key. .

• It is made from pairs of It is made from pairs of contrasting characteristics (e.g., contrasting characteristics (e.g., has wings/does not have wings). has wings/does not have wings).

Wacky People Key

1a Two feet 2

1b Some other number of feet 3

2a Does not look at all human 4

2b Looks a lot like a human 5

3a One leg 6

3b Three or four legs 7

4a Fly-like Mosk Cara

4b Not fly-like 8

5a Seems to be a girl Rita Nita

5b Not a girl 9

6a Leg is curled , two feet Ru-ela.Brella

6b Leg is straight, one foot Giggles

7a Three legs 10

7b Four legs 11

8a Has webbed feet Hex Oculate

8b Clawed feet 12

9a Curly hair, no toes Lugio Wirum

9b Wiggly looking mouth, three toes on feet C. Nile

10a Very long nose, open mouth Elle E. Funk

10b Some other appearance 13

11a Has duck bill, two pinchers Tri D. Duckt

11b No arms or pinchers 14

12a Has ears, tail, and beak Grif Leon

12b Four eyes on stalks Eggur Ondy

13a One eye, webbed feet Cue Kide

13b Four stalked eyes, four pinchers Quadrumenox

14a Three toed feet, nose like a flower Tunia petalos

14b Spider-like, has spots Patterned mulywumpus

AnyAny

Questions ???Questions ???