ORGANISMAL DIVERSITY
AND SYSTEMS OF
CLASSIFICATION:
Taxonomy and Phylogeny
Why Classify?
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Why Classify?
19 Now the LORD God had formed out of the ground
all the beasts of the field and all the birds of the air. He
brought them to the man to see what he would name
them; and whatever the man called each living
creature, that was its name. 20 So the man gave names
to all the livestock, the birds of the air and all the beasts
of the field. Genesis 2:19-20a, NIV
http://www.youtube.com/watch?v=JHFXG3r_0B8
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CLASSIFICATION

Taxonomy (old)



The systematic classification of organisms
Sorted by common morphological
characteristics
Phylogeny (modern)

Cladistic approach (family trees)

Sorted by molecular similarity

Actual relatedness, not appearance
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Taxa (Plural form of “Taxon”)

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species
more general
more specific
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Taxa

Domain

Daring

Kingdom

Kids

Phylum

Playing

Class

Carelessly

Order

On

Family

Freeways

Genus

Get

Species

Squashed
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Naming Organisms: The Binomial System

Carolus Linnaeus (1700’s)

Binomial nomenclature

2 part names: Genus species

Rules

Latin (Latinized)

1st word capitalized

Both words italicized

E.g., Streptococcus thermophilus
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Why Classify?
Robins…
European Robin
American Robin
Erithacus rubecula
Turdus migratorius
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Definition of a Species
A group of organisms that …

share common physical characteristics

can be distinguished from other species

don’t “normally” interbreed with other species in
nature (interbreeding produces sterile offspring)
BALTIMORE ORIOLE
BULLOCK’S ORIOLE
BULLOCK’S
ORIOLE
BALTIMORE
ORIOLE
Fig. 19.15 p. 305
HYBRID ZONE
Slide 16
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Modern Taxonomy

Carl Woese (1980’s)

“genetic markers”


Molecular clocks – DNA, RNA, protein
Ribosomal RNA (rRNA)

Present in cells of all living
organisms

Functional homology

Structurally conserved

Heritable
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Molecular Clocks
Fig. 18.7
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Cladograms: “Phylogenetic Family Trees”

Visual representation of systems of
categorizations

Clade: monophyletic group consisting of an
ancestor and all its descendents


Parsimony analysis
Nodes (branch points): a common ancestor
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Mary Sittel
Nadine Millhollen
Connie Miller
Elwine _____
Wilhelm Nell
Margarete Nell
Elizabeth DuPriest-Melo
Charles Miller
Anna Bodler
Robert DuPriest, Jr.
Robert DuPriest, Sr.
Johann Miller
Karl Miller
Agatha Doucet
Rosa _______
Fernando R. Melo
Fernando A. Melo
Fernando J. Melo
Roxana Mendoza
Sports
Sports played with a ball
Sports played with a round ball
Sports played
in water
hagfishes
lampreys
cartilaginous fishes
ray-finned fishes
lobe-finned fishes
lungfishes
animals with a skull
animals with a backbone
and a skull
animals with a swim
bladder or lungs, a
backbone, and a skull
amphibians
animals with four limbs,* a
swim bladder or lungs, a
backbone, and a skull
amniotes
(reptiles,
birds, and
mammals)
animals with four
membranes around their
eggs, four limbs,* a swim
bladder or lungs, a
backbone, and a skull
* Snakes are included in
these clades because their
ancestors had four legs.
Fig. 19-3b, p. 303
3 Domains

Bacteria



Pathogens, N-fixers,
food fermentation
Archaea

“Ancient” bacteria

Extreme environments
Eukarya

All other living
organisms
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6 Kingdoms

Bacteria

Eubacteria

Archaea

Archaebacteria

Eukarya

Protista
Fungi
Plantae
Animalia
Bacteria
Archaea
Protista
Plants
Fungi Animals
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6 Kingdom Phylogenetic Tree
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Classification of the human species

Domain

Eukarya

Kingdom

Animalia

Phylum

Chordata
(nerve cord)

Class

Mammalia
(hair, mammary glands)

Order

Primate
(binoc. vision, opp. thumbs)

Family

Hominidae
(bipedal)

Genus

Homo
(larger brain)

Species

sapiens
(“wise man”)
(eukaryotic cell structure)
(heterotrophs, no cell wall, NS)
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