Taxonomy
Biology 8(A)
Taxonomy
Learning Objectives
• Define taxonomy
• Understand the importance of a standardized taxonomic
system
Taxonomy
Taxonomy – the branch of biology that classifies and names
living things
• Uses characteristics of organisms and a universal system
– Every organism has a specific name
– Organisms are assigned to levels of classification
Common Name vs. Scientific Name
Common name – name given to an organism by the people
of a certain area
• Causes great deal of confusion
• Examples:
– Mountain lion
– Puma
– Cougar
Linnaeus’ System
Carolus Linnaeus – Swedish botanist
who developed new classification
system that revolutionized taxonomy
Contributions
• Created two-word (binomial) scientific naming system
• Suggested that organisms with similar
structures be placed in same taxonomic group
Common Name vs. Scientific Name
Scientific name – standard name accepted by all scientists
Binomial nomenclature – scientific naming system using
Latin language
• First name – genus
• Second name – specific name
• Both names – species
– Felis concolor or Felis concolor
– F. concolor or F. concolor
Levels of Taxonomy
Kingdom
Phylum
Class
Order
Family
Genus
Species
Taxonomy
Levels of Classification
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species
Classification of Humans:
• Animalia
• Chordata
• Mammalia
• Primates
• Hominidae
• Homo
• Homo Sapiens
Taxonomy
Levels of Classification
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species
Levels of Classification
• Kings
• Play
• Chess
• On
• Fancy
• Glass
• Squares
Taxonomy
Importance of a standardized taxonomic system
• Needed to orderly classify vast diversity of organisms
• Allows for universal understanding
• Ability for similarities to be compared
• Show common ancestry
Taxonomy
Learning Objectives
• Define taxonomy
• Understand the importance of a standardized taxonomic
system
Classifying Organisms
Biology 8(B)
Classifying Organisms
Learning Objectives
• Categorize organisms using a hierarchical classification
system based on similarities and differences shared among
groups
– Using characteristics of major groups
– Using dichotomous keys
Classifying Organisms
Taxonomy – the science of classifying organisms
Taxonomists use a seven level classification system
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species
Classifying Organisms
Comparing the classification of a domestic housecat and a
mountain lion:
Mountain Lion
Domestic Cat
Kingdom
Animalia
Animalia
Phylum
Chordata
Chordata
Class
Mammalia
Mammalia
Order
Carnivora
Carnivora
Family
Felidae
Felidae
Genus
Felis
Felis
Specific name
concolor
domesticus
Classifying Organisms
Comparing the classification of the wolf and a polar bear:
Wolf
Polar Bear
Kingdom
Animalia
Animalia
Phylum
Chordata
Chordata
Class
Mammalia
Mammalia
Order
Carnivora
Carnivora
Family
Canidae
Urisdae
Genus
Canis
Ursus
Specific name
lupis
maritimus
Taxonomic Groups
All living organisms are grouped into one of a few major
categories.
• Most widely accepted classification system used by
taxonomists groups organisms into six major groups or
kingdoms
–
–
–
–
–
–
Archaea
Bacteria
Protista
Fungi
Plantae
Animalia
Archaea
Archaea – single-celled
microorganisms
Image by Wing-Chi Poon [CC-BY-1.0]
• Examples:
– Methane-producing archaea
– Sulfur-producing archaea
– Thermophiles
Characteristics
• Microscopic
• Many live in extreme
environments
• Unicellular
prokaryotes
• Unique cell wall
• Autotrophs or
heterotrophs
Bacteria
Bacteria – single-celled
microorganisms
• Examples:
–
–
–
–
E. coli
Salmonella
Streptococcus
Staphylococcus
Characteristics
• Microscopic
• Unicellular
prokaryotes
• Cell wall made of
peptidoglycan
• Autotrophs or
heterotrophs
Protista
Protista – most diverse
kingdom
• Examples:
–
–
–
–
Algae
Paramecia
Amoeba
Diatoms
Characteristics
• Unicellular or
multicellular
• Eukaryotes
• Autotrophic or
heterotrophic
• Some have cell walls
• Many are microscopic
• Many are aquatic
• Some are motile
Fungi
Fungi – similar to plants but
not photosynthetic
Characteristics
• All eukaryotes
– Some unicellular
– Most multicellular
Image by Maciej Lewandowski [CC-BY-1.0]
• Examples:
– Mushrooms
– Yeasts
– Molds
• Cell wall made of
chitin
• Absorb nutrients
• Many are saprobes
• All sessile
Plantae
Plantae – both vascular and
nonvascular plants
Characteristics
• All eukaryotes
– Most multicellular
– Some unicellular
Image by Eric Guinther [CC-BY-1.0]
• Examples:
–
–
–
–
Mosses
Ferns
Conifers
Flowering plants
• Cell wall made of
cellulose
• Photosynthetic
autotrophs
• Contain chloroplasts
• Sessile
Animalia
Animalia – most complex
kingdom
• Vertebrates
• Invertebrates
Image by Eric Guinther [CC-BY-1.0]
• Examples:
–
–
–
–
Mammals
Birds
Insects
Worms
Characteristics
• Multicellular
(eukaryotes)
• No cell walls
• Heterotrophic
• Most are motile
Taxonomic Groups
Group
(Kingdom)
Archaea
Bacteria
Protista
Fungi
Plantae
Animalia
Major Characteristics
Examples
Prokaryotes, cell wall, may live in extreme
environments, unicellular, autotrophs or
heterotrophs
Prokaryotes, cell wall made of peptidoglycan,
unicellular, autotrophs or heterotrophs
Methane-producing archaea,
thermophiles
E. coli, salmonella
Eukaryotes, unicellular or multicellular,
Algae, paramecia, euglena,
autotrophs or heterotrophs, some have cell wall, diatoms
many are microscopic
Eukaryotes, most are multicellular, cell walls,
Mushrooms, molds, yeasts
absorbs nutrients through cell wall, sessile
Eukaryotes, most are multicellular, cell walls
composed of cellulose, photosynthetic,
autotrophs
Eukaryotes, multicellular, heterotrophs, most
are motile
Ferns, mosses, conifers,
flowering plants
Mammals, birds, insects, worms,
sponges
What kingdom does this organism
belong to?
A new organism is discovered by a microbiologist. The organism
is unicellular, lacks chloroplasts, and has no cell wall. Into which
of the six kingdoms should this organism be placed?
Group
(Kingdom)
Archaea
Major Characteristics
Examples
Bacteria
Prokaryotes, cell wall made of peptidoglycan,
unicellular, autotrophs or heterotrophs
Protista
Eukaryotes, unicellular or multicellular, autotrophs or
Algae, paramecia, euglena, diatoms
heterotrophs, some have cell wall, many are microscopic
Fungi
Eukaryotes, most are multicellular, cell walls, absorbs
nutrients through cell wall, sessile
Mushrooms, molds, yeasts
Plantae
Eukaryotes, most are multicellular, cell walls composed
of cellulose, photosynthetic, autotrophs
Ferns, mosses, conifers, flowering
plants
Animalia
Eukaryotes, multicellular, heterotrophs, most are motile
Mammals, birds, insects, worms,
sponges
Prokaryotes, cell wall, may live in extreme environments, Methane-producing archaea,
unicellular, autotrophs or heterotrophs
thermophiles
E. coli, salmonella
What kingdom does this organism
belong to?
An organism is found growing on your bathroom wall. It is
multicellular, and does not appear to be moving. What kingdom do you
think it belongs in?
Group
(Kingdom)
Archaea
Major Characteristics
Examples
Bacteria
Prokaryotes, cell wall made of peptidoglycan,
unicellular, autotrophs or heterotrophs
Protista
Eukaryotes, unicellular or multicellular, autotrophs or
Algae, paramecia, euglena, diatoms
heterotrophs, some have cell wall, many are microscopic
Fungi
Eukaryotes, most are multicellular, cell walls, absorbs
nutrients through cell wall, sessile
Mushrooms, molds, yeasts
Plantae
Eukaryotes, most are multicellular, cell walls composed
of cellulose, photosynthetic, autotrophs
Ferns, mosses, conifers, flowering
plants
Animalia
Eukaryotes, multicellular, heterotrophs, most are motile
Mammals, birds, insects, worms,
sponges
Prokaryotes, cell wall, may live in extreme environments, Methane-producing archaea,
unicellular, autotrophs or heterotrophs
thermophiles
E. coli, salmonella
What kingdom does this organism
belong to?
Rana pipiens is an organism about the size of your hand. Its cells are
eukaryotic and it eats other members of its own kingdom. It is an
excellent swimmer. What kingdom does Rana pipiens belong in?
Group
(Kingdom)
Archaea
Major Characteristics
Examples
Bacteria
Prokaryotes, cell wall made of peptidoglycan,
unicellular, autotrophs or heterotrophs
Protista
Eukaryotes, unicellular or multicellular, autotrophs or
Algae, paramecia, euglena, diatoms
heterotrophs, some have cell wall, many are microscopic
Fungi
Eukaryotes, most are multicellular, cell walls, absorbs
nutrients through cell wall, sessile
Mushrooms, molds, yeasts
Plantae
Eukaryotes, most are multicellular, cell walls composed
of cellulose, photosynthetic, autotrophs
Ferns, mosses, conifers, flowering
plants
Animalia
Eukaryotes, multicellular, heterotrophs, most are motile
Mammals, birds, insects, worms,
sponges
Prokaryotes, cell wall, may live in extreme environments, Methane-producing archaea,
unicellular, autotrophs or heterotrophs
thermophiles
E. coli, salmonella
Cladograms
Clade – group of related organisms
Cladogram – branching diagram showing evolutionary
descent
C
B
A
Properties of cladogram
• Each split represents appearance
of new trait(s)
• Related organisms are closer together
new trait(s)
new trait(s)
Cladograms
Cladogram – branching diagram showing evolutionary
descent
What can be determined from this cladogram?
Lemurs
Lorises
Tarsiers New world Old world Apes
• Primates share
Monkeys Monkeys
common ancestor
• Humans more closely
related to apes than to
monkeys
• Lemurs lack traits
common to monkeys
Humans
Cladograms
Cladogram of a group of animals
Tuataras
Lizards
Snakes
Crocodiles
Birds
What can be determined from this cladogram?
• Tuataras are not lizards
• Birds share common ancestor with reptiles
• Snakes are more closely related to lizards than crocodiles
Image modified from Benchill [GNU]
Dichotomous Key
Dichotomous key – tool used to identify organisms
• Also called classification key
• Helps user observe similarities and differences among
organisms
• Each step presents a level of identification
– Only one of the statements in a step can be true about a single
organism
Dichotomous Key
What is the scientific name of this seashell?
Seashell Dichotomous Key
Image by Shellnut
(Own work) [CC-BY-SA-3.0]
1a Cone-shaped
1b Not cone-shaped
Go to 2
Go to 5
2a Outside surface smooth
2b Outside surface rigid
Go to 3
Go to 4
3a Surface solid color
3b Surface spotted
Conus californicus
Conus spurius
4a Surface one color
4b Surface has contrasting stripe
Calliostoma supragranulosa
Calliostoma annulatum
5a Holes along shell margin
5b No holes along shell margin
Haliotis refuscens
Go to 6
6a Purple in color
6b Not purple in color
Janthina janthina
Littorina obtusata
Dichotomous Key
What is the scientific name of this seashell?
Seashell Dichotomous Key
Image by Hans Hillewaert
(Own work) [CC-BY-SA-3.0]
1a Cone-shaped
1b Not cone-shaped
Go to 2
Go to 5
2a Outside surface smooth
2b Outside surface rigid
Go to 3
Go to 4
3a Surface solid color
3b Surface spotted
Conus californicus
Conus spurius
4a Surface one color
4b Surface has contrasting stripe
Calliostoma supragranulosa
Calliostoma annulatum
5a Holes along shell margin
5b No holes along shell margin
Haliotis refuscens
Go to 6
6a Purple in color
6b Not purple in color
Janthina janthina
Littorina obtusata
Dichotomous Key
What is the scientific name of this seashell?
Seashell Dichotomous Key
1a Cone-shaped
1b Not cone-shaped
Go to 2
Go to 5
2a Outside surface smooth
2b Outside surface rigid
Go to 3
Go to 4
3a Surface solid color
3b Surface spotted
Conus californicus
Conus spurius
4a Surface one color
4b Surface has contrasting stripe
Calliostoma supragranulosa
Calliostoma annulatum
5a Holes along shell margin
5b No holes along shell margin
Haliotis refuscens
Go to 6
6a Purple in color
6b Not purple in color
Janthina janthina
Littorina obtusata
Dichotomous Key
Is this animal a vertebrate or invertebrate? If it is a
vertebrate, what class does it belong in?
Vertebrate Animal Dichotomous Key
Image by Dario Sanches
(Own Work) [CC-BY-SA-2.0]
1a Spinal column present
1b Spinal column absent
Go to 2
Invertebrate
2a Fins and gills present
2b Fins and gills absent
Fish
Go to 3
3a Scales present
3b Scales absent
Reptile
Go to 4
4a Feathers present
4b Feathers absent
Bird
Go to 5
5a Hair or fur present
5b Hair or fur absent
Mammal
Amphibian
Dichotomous Key
Is this animal a vertebrate or invertebrate? If it is a
vertebrate, what class does it belong in?
Vertebrate Animal Dichotomous Key
1a Spinal column present
1b Spinal column absent
Go to 2
Invertebrate
2a Fins and gills present
2b Fins and gills absent
Fish
Go to 3
3a Scales present
3b Scales absent
Reptile
Go to 4
4a Feathers present
4b Feathers absent
Bird
Go to 5
5a Hair or fur present
5b Hair or fur absent
Mammal
Amphibian
Dichotomous Key
Is this animal a vertebrate or invertebrate? If it is a
vertebrate, what class does it belong in?
Vertebrate Animal Dichotomous Key
1a Spinal column present
1b Spinal column absent
Go to 2
Invertebrate
2a Fins and gills present
2b Fins and gills absent
Fish
Go to 3
3a Scales present
3b Scales absent
Reptile
Go to 4
4a Feathers present
4b Feathers absent
Bird
Go to 5
5a Hair or fur present
5b Hair or fur absent
Mammal
Amphibian
Classifying Organisms
Learning Objectives
• Categorize organisms using a hierarchical classification
system based on similarities and differences shared among
groups
– Using characteristics of major groups
– Using dichotomous keys