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ORGANISMAL DIVERSITY

AND SYSTEMS OF

CLASSIFICATION:

Taxonomy and Phylogeny

Why Classify?

2

Why Classify?

3 http://www.youtube.com/watch?v=JHFXG3r_0B8

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

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 4

Taxa (Plural form of “Taxon”)

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

more general

more specific

5

Taxa

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Daring

Kids

Playing

Carelessly

On

Freeways

Get

Squashed

6

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

7

Why Classify?

Robins…

European Robin

Erithacus rubecula

American Robin

Turdus migratorius

8

Definition of a Species

A group of organisms that …

Slide 16

Fig. 19.15 p. 305

BULLOCK’S

ORIOLE

BALTIMORE

ORIOLE

HYBRID ZONE

BULLOCK’S ORIOLE BALTIMORE ORIOLE

share common physical characteristics

can be distinguished from other species

don’t “normally” interbreed with other species in

nature (interbreeding produces sterile offspring)

9

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

10

Molecular Clocks

11 Fig. 18.7

Cladograms: “Phylogenetic Family Trees”

12

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

Elizabeth DuPriest-Melo

Fernando R. Melo

Fernando A. Melo Roxana Mendoza

Fernando J. Melo

Rosa _______

Connie Miller Robert DuPriest, Jr.

Robert DuPriest, Sr.

Nadine Millhollen

Charles Miller

Mary Sittel

Johann Miller Karl Miller

Anna Bodler

Margarete Nell Wilhelm Nell

Elwine _____

Agatha Doucet

Sports

Sports played with a ball

Sports played with a round ball

Sports played

in water

Fig. 19-3b, p. 303

hagfishes animals with a skull

lampreys

cartilaginous fishes animals with a backbone

and a skull

ray-finned fishes animals with a swim

bladder or lungs, a

backbone, and a skull lobe-finned fishes

lungfishes animals with four limbs,* a

swim bladder or lungs, a

backbone, and a skull amphibians

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.

3 Domains

Bacteria

Pathogens, N-fixers,

food fermentation

Archaea

“Ancient” bacteria

Extreme environments

Eukarya

All other living

organisms

16

6 Kingdoms

Bacteria Eubacteria

Archaea Archaebacteria

Eukarya Protista

Fungi

Plantae

Animalia

17

Bacteria Archaea Protista Plants Fungi Animals

18 6 Kingdom Phylogenetic Tree

Classification of the human species

Domain Eukarya (eukaryotic cell structure)

Kingdom Animalia (heterotrophs, no cell wall, NS)

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”)

19