Honors
Biology
Ch.17
Organizing
Life’s Diversity
I. The History of Classification
Taxonomy:
- the science of identifying, naming,
and classifying organisms
A. Early Classification Systems
1. Aristotle:
a. Devised First Classification System
- Animals (red-blooded and bloodless)
- Plants (trees, shrubs, and herbs)
- 2 problems:
1) superficial categories
2) used common names
B. Disadvantages of Common Names:
1.Confusing
- ex. mountain lion, cougar, puma,
panther, catamount
Puma concolor
2.Misleading
- starfish, jellyfish, cuttlefish,
crawfish, silverfish
3.Language Problems
- local names
- names used by different languages
- some organisms have no common name
Microplitis demolitor
2. Carolus Linnaeus
- developed modern
classification
system
- Swedish botanist
(1700’s)
- 2 important
innovations:
a. Binomial Nomenclature
- two-word naming system:
genus & species
- gives a unique,
universal name
for every species
Carolus Linnaeus
Honey Bee
Apis mellifera
Apis pubescens, thorace subgriseo,
abdomine fusco, pedibus posticis glabris,
utrinque margine ciliatus
1) Genus:
- 1st word, small group
- usually a Latin noun, capitalized
2) Species:
- 2nd word, particular type
- Latin adjective, lower case
3) Examples:
- Homo sapiens
- Tyrannosaurus rex
humans
3) Examples:
- Acer rubrum
- Acer saccharum
- Acer macrophyllum
Acer rubrum
Acer saccharum
red maple
sugar maple
bigleaf maple
Acer macrophyllum
Acer pennsylvaticum
Acer circinatum
3) Examples:
- Sequoia giganteum
- Tsuga heterophylla
- Pseudotsuga menziesii
giant sequoia
western hemlock
Douglas-fir
b. Hierarchy of Classification
Groupings
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Eukarya
Animalia
Chordata
Mammalia
Carnivora
Canidae
Canis
lupus
b. Hierarchy of Classification
Groupings
Did
Domain
Eukarya
King
Kingdom
Animalia
Phillip
Phylum
Chordata
come
Class
Mammalia
often
Order
Carnivora
for
Family
Canidae
ginger
Genus
Canis
snaps?
Species
lupus
Hierarchy
of Taxa
II. Taxonomy Today
- Classification systems change
constantly.
- Taxonomists do not always agree on
how to classify organisms.
A.Determining Species
1. Typological Species Concept
- a group of organisms that are
physically similar to each other
2. Biological Species Concept
- a group of organisms
that is able to
interbreed and produce
fertile offspring in a
natural setting
- cannot be used with
extinct or asexual
organisms
Similarity between
different species
Diversity within a species
3. Phylogenetic Species Concept
- defines a species as a set of organisms
with a unique genetic history
Species A, B, and C each have its own
common ancestor shared by no other group.
B. Characters
- inherited features (morphological or
biochemical) that vary among
organisms
1. Morphological Characters
- similarities indicate common ancestry
- include homologous structures:
different functions but similar
underlying anatomy
- does not include analogous
structures: similar functions but
different underlying anatomy
Marsupial ‘Mole’
Eastern Mole
2. Biochemical Characters
- The greater the
similarities in
certain compounds
(DNA, proteins,
etc.), the more
closely related
organisms are.
Species
Percent of Amino Acids That Are
Identical to the Amino Acids in a
Human Hemoglobin Polypeptide
100%
Human
Rhesus monkey
95%
Mouse
87%
Chicken
69%
Frog
Comparison of a
Protein Found in
Diverse Vertebrates
Lamprey
54%
14%
A Molecular
Homology
3. Molecular “Clock”
- Mutations occur randomly and
accumulate over time.
- Mutations that
don’t affect
survival can be
used to estimate
time.
The Constant Rate of
Evolution of the α-globin
C. Phylogenetic
Reconstruction
- Phylogeny is the
evolutionary
history of
a species.
Phylogeny of Whales
1. Character Types
- Ancestral characters are shared
by ancestral organism and all of
its descendents.
- Derived characters are
Leopard
Turtle
shared by one group
Hair
Salamander
of organisms
Amniotic egg
but not the
Tuna
ancestor.
Four walking legs
Lamprey
Hinged jaws
Lancelet (outgroup)
Vertebral column
Phylogenetic Tree of Chordates
2. Cladograms (Phylogenetic Tree)
- a branching diagram that represent the
proposed phylogeny of a group of organisms
Phylogenetic
Tree of
Dinosaurs
Ursininae
Tremarclinae
Ailuropodinae
Procyonidae
Ailuridae
Ursidae
Phylogeny
of Bears
Musteloidae
Caniformia
III. Domains and Kingdoms
- Most scientists today use the 3
domain system to classify organisms:
Bacteria, Archaea, and Eukarya.
Sulfolobus
Thermophiles
Halophiles
COMMON
ANCESTOR
OF ALL
LIFE
Methanobacterium
ARCHAEA
The Three
Domains
of Life
Sulfolobus
Green nonsulfur bacteria
Thermophiles
Halophiles
(Mitochondrion)
COMMON
ANCESTOR
OF ALL
LIFE
Methanobacterium
ARCHAEA
The Three
Domains
of Life
Spirochetes
Chlamydia
BACTERIA
Cyanobacteria
(Plastids, including
chloroplasts)
EUKARYA
Dinoflagellates
Forams
Diatoms
Ciliates
Red algae
Land plants
Green algae
Cellular slime molds
Amoebas
Euglena
Trypanosomes
Leishmania
Animals
Fungi
Sulfolobus
Green nonsulfur bacteria
Thermophiles
Halophiles
(Mitochondrion)
COMMON
ANCESTOR
OF ALL
LIFE
Spirochetes
Chlamydia
BACTERIA
Methanobacterium
ARCHAEA
The Three
Domains
of Life
Cyanobacteria
(Plastids, including
chloroplasts)
A.Domain Bacteria
- includes the kingdom
Eubacteria
- prokaryotes whose
cell walls contain
peptidoglycan
- includes many
familiar bacteria
such as E. coli,
Streptococcus, etc.
B.Domain Archaea
- Prokaryotes that
represent an ancient
form of life
- more closely related
to our eukaryotic
ancestors
- called extremophiles
because they can
live in extreme
environments
C. Domain Eukarya
- includes all eukaryotes
- contains:
Kingdom Protista
Kingdom Plantae
Kingdom Fungi
Kingdom Animalia
1.Kingdom Protista
(no longer considered a valid kingdom)
- eukaryotic organisms
- unicellular, colonial, or multicellular
2.Kingdom Plantae
- photosynthetic multicellular eukaryotes
- have cell walls made of cellulose
- nonmotile
3. Kingdom Fungi
-
unicellular or multicellular eukaryote
heterotrophic (absorb nutrients)
have cell walls made of chitin
nonmotile
3. Kingdom Fungi
- unicellular or multicellular eukaryote
- heterotrophic (absorb nutrients)
- have cell walls
made of chitin
- nonmotile
4.Kingdom Animalia
- heterotrophic, multicellular eukaryotes
- complex organ systems
- motile
- obtain
food by
ingestion
The
End
- Order Carnivora
Linking Classification and Phylogeny
Order
Family Genus
Species
Taxidea
Taxidea
taxus
Lutra
Mustelidae
Panthera
Felidae
Carnivora
Panthera
pardus
Lutra lutra
Canis
Canidae
Canis
latrans
Canis
lupus
A Phylogenetic Tree of Birds
and Their Close Relatives
Lizards
and snakes
Crocodilians
Common
ancestor of
crocodilians,
dinosaurs,
and birds
Ornithischian
dinosaurs
Saurischian
dinosaurs
Birds
Phylogeny of Horses
Recent
(11,500 ya)
Equus
Pleistocene
(1.8 mya)
Hippidion and other genera
Nannippus
Pliohippus
Hipparion Neohipparion
Pliocene
(5.3 mya)
Sinohippus
Megahippus
Callippus
Archaeohippus
Miocene
(23 mya)
Merychippus
Hypohippus
Anchitherium
Parahippus
Miohippus
Oligocene
(33.9 mya)
Mesohippus
Paleotherium
Epihippus
Propalaeotherium
Eocene
(55.8 mya)
Pachynolophus
Orohippus
Key
Hyracotherium
Grazers
Browsers
Phylogeny of Elephants
Phylogeny of Cats
Phylogeny
of Dogs
2. Biological Species Concept
The butterflies on the top row were born in the
Spring (cooler, shorter days). Those in the bottom
row were born in summer (warmer, longer days).