Opening Activity
!  Latin Root Word: Tax-
Taxonomy
CLASSIFYING ORGANISMS
Taxonomy
!  Taxnomy-involves
identification, naming
and classification of
species
!  Carolus Linnaeus-used a
two part Latin name
called a binomal
nomenclature.
Binomial Nomenclature
!  Species name has two parts (Genus and species
identifier)
"  Genus
species
"  Homo sapiens = Humans
!  Two part name = binomial nomenclature (Latin)
Why?
!  To overcome regional
names.
!  Example: Mountain
lions-depending on
where you are, this
creature has a different
name.
!  Some names are
deceiving: cat fish,
crayfish, and silverfish
Devil Cat
Ghost Cat
Mountain Lion
Screaming Cat
Puma
Florida Panther
Cougar
The Linnaean classification system has limitations.
!  Linnaeus taxonomy doesn’t account for molecular
evidence.
The technology didn’t exist during Linneaus’ time.
!  Linnaean system based only on physical similarities.
! 
•  Physical similarities are not always
the result of close relationships.
•  Genetic similarities more accurately
show evolutionary relationships.
Classification
Evolutionary Categorization
!  Phylogenetic Tree-a
diagram that reflects
possible evolutionary
relationships with
branches to help classify
organisms.
! 
Based on similarities in
the fossil record, stages of
development, biomolecule
similarities.
Cladistics - is a relatively new
system of phylogenetics
classification that uses shared
derived characters to establish
evolutionary relationships. A
derived character is a feature
that apparently evolved only
within the group under
consideration.
!  Cladistics is a common method to make evolutionary trees.
–  classification based on common ancestry
–  species placed in order that they descended from common ancestor
A phylogenetic tree based on a
cladistic analysis is called a
cladogram.
What derived character is shared by
all the animals on the cladogram on
the next slide?
•  Derived characters are traits shared in different degrees by clade
members.
–  basis of arranging species
in cladogram
–  more closely related
species share more
derived characters
–  represented on
cladogram as hash marks
1 Tetrapoda clade
2 Amniota clade
3 Reptilia clade
4 Diapsida clade
5 Archosauria clade
FEATHERS &
TOOTHLESS
BEAKS.
SKULL OPENINGS IN
FRONT OF THE EYE &
IN THE JAW
OPENING IN THE SIDE OF
THE SKULL
SKULL OPENINGS BEHIND THE EYE
EMBRYO PROTECTED BY AMNIOTIC FLUID
FOUR LIMBS WITH DIGITS
DERIVED CHARACTER
•  Nodes represent the most
recent common ancestor
of a clade.
CLADE
1 Tetrapoda clade
2 Amniota clade
3 Reptilia clade
•  Clades can be identified
by snipping a branch
under a node.
4 Diapsida clade
5 Archosauria clade
FEATHERS AND
TOOTHLESS
BEAKS.
SKULL OPENINGS IN
FRONT OF THE EYE
AND IN THE JAW
OPENING IN THE SIDE OF
THE SKULL
SKULL OPENINGS BEHIND THE EYE
EMBRYO PROTECTED BY AMNIOTIC FLUID
NODE
FOUR LIMBS WITH DIGITS
DERIVED CHARACTER
The Dichotomous Key
•  A key is a device for easily and quickly
identifying an unknown organism.
•  The dichotomous key is the most widely used
type of classification tool in biological sciences.
•  The user is presented with a sequence of
choices between two statements, couplets,
based on characteristics of the organism. By
always making the correct choice, the name of
the organism will be revealed.
A. one pair of wings
1.
B. Two pairs of wings
Taxonomy
!  Taxnomy-involves
identification, naming
and classification of
species
!  Carolus Linnaeus-used a
two part Latin name
called a binomal.
!  First part = genus
!  Second part = speceis
!  Example: Pantera onca
Classification
Things change
!  The classification system has undergone some
changes due to advances in DNA technology
!  Originally, there were only two kingdoms, plants and
animals.
!  What about protists, fungi and prokaryotes?
!  Eventually ended up with the 6 kingdom system of
today, which are under the three domains.
Classification is always a work in progress.
!  The tree of life shows our most current understanding.
!  New discoveries can lead to changes in classification.
! 
Until 1866: only two kingdoms,
Animalia and Plantae
Animalia!
Plantae!
Classification is always a work in progress.
!  The tree of life shows our most current understanding.
!  New discoveries can lead to changes in classification.
! 
Until 1866: only two kingdoms,
Animalia and Plantae
Animalia!
–  1866: all single-celled organisms
moved to kingdom Protista
Plantae!
Protista!
Classification is always a work in progress.
!  The tree of life shows our most current understanding.
!  New discoveries can lead to changes in classification.
! 
Until 1866: only two kingdoms,
Animalia and Plantae
Animalia!
–  1866: all single-celled organisms
moved to kingdom Protista
Plantae!
Protista!
–  1938: prokaryotes moved to
kingdom Monera
Monera!
Classification is always a work in progress.
!  The tree of life shows our most current understanding.
!  New discoveries can lead to changes in classification.
! 
Until 1866: only two kingdoms,
Animalia and Plantae
Plantae!
Animalia!
–  1866: all single-celled organisms
moved to kingdom Protista
Protista!
–  1938: prokaryotes moved to
kingdom Monera
–  1959: fungi moved to own
kingdom
Monera!
Fungi!
Classification is always a work in progress.
!  The tree of life shows our most current understanding.
!  New discoveries can lead to changes in classification.
! 
Until 1866: only two kingdoms,
Animalia and Plantae
Plantae!
Animalia!
–  1866: all single-celled organisms
moved to kingdom Protista
Protista!
–  1938: prokaryotes moved to
kingdom Monera
Archea!
–  1959: fungi moved to own
kingdom
Fungi!
–  1977: kingdom Monera
split into kingdoms Bacteria and Archaea
Bacteria
The three domains in the tree of life are Bacteria,
Archaea, and Eukarya.
!  Domains are above the kingdom level.
!  proposed by Carl Woese based on rRNA studies of prokaryotes
!  domain model more clearly shows prokaryotic diversity
Six Kingdom System
!  Currently use two alternative classification systems
!  6 Kingdom system
"  Kingdom:
Animalia
Archaebacteria, Eubacteria, Protista, Fungi, Plantae,
Kingdom Archaebacteria
!  Unicellular prokaryotes
!  Archae- : “ancient”
!  Autotrophic: produce food by chemosynthesis
!  Evolved before photosynthesis
!  Live in harsh environments
!  Swamps, salt lakes, and hot springs
!  Methanogens: produce methane gas from H2 and
CO2
!  Extreme Halophiles: salt loving
!  Thermoacidophiles: live in acidic environments
(hot springs, hydrothermal vents)
Kingdom Eubacteria
!  “True Bacteria”
!  Most use oxygen
!  Unicellular prokaryotes
!  Kingdom Eubacteria and Archaebacteria =
Greatest number of living things on earth
!  Cause tooth decay, strep throat, food poisoning
(Salmonella)
!  Accounts for most bacteria
Kingdom Protista
!  Contains all Eukaryotes that are not plants,
animals, or fungi
!  Protozoa
"  Phylum
Sarcodina: Amoebas: amebic dysentery
"  Phylum Ciliophora: Paramecium
"  Phylum Zoomastigina: zooflagellates: Leishmaniasis
"  Phylum Sporozoa: Plasmodium: Malaria
!  algae
!  slime
molds
!  water molds
Kingdom Fungi
!  Heterotrophic unicellular and multicellular
organisms
!  Absorb nutrients instead of ingesting them
!  Mushrooms, puffballs, rusts, smuts, mildews, and
molds.
Kingdom Plantae
!  Multicellular
!  Autotrophic and use photosynthesis as a source of
energy
!  Most live on land and have a sexual cycle based on
meiosis
Kingdom Animalia
!  Eukaryotic, multicellular, heterotrophic organisms
!  Have symmetrical body organization
!  Have standard sexual cycle based on meiosis and the
recombination of genes.
Three Domain System
!  Compare sequences of ribosomal RNA in different
organisms to estimate how long ago pairs of
different organisms shared a common ancestor
!  Domain Archae = Kingdom Archae bacteria
(Prokaryotic)
!  Domain Bacteria = Kingdom Eubacteria
(Prokaryotic)
!  Domain Eukarya = Kingdom Protista, Plantae,
Fungi, Animalia (Eukaryotic)
•  Domain Bacteria includes prokaryotes in the kingdom Bacteria.
–  one of largest groups on Earth
–  classified by shape, need for
oxygen, and diseases caused
•  Domain Archaea includes prokaryotes in the kingdom Archaea.
–  cell walls chemically different from
bacteria
–  differences discovered by studying
RNA
–  known for living in extreme
environments
•  Domain Eukarya includes all eukaryotes.
–  kingdom Protista
•  Domain Eukarya includes all eukaryotes.
–  kingdom Protista
–  kingdom Plantae
•  Domain Eukarya includes all eukaryotes.
–  kingdom Protista
–  kingdom Plantae
–  kingdom Fungi
•  Domain Eukarya includes all eukaryotes.
–  kingdom Protista
–  kingdom Plantae
–  kingdom Fungi
–  kingdom Animalia
•  Bacteria and archaea can be difficult to classify.
–  transfer genes among themselves outside of reproduction
–  blurs the line
between “species”
bridge to transfer DNA
–  more research
needed to
understand
prokaryotes