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CLASSIFICATION
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• There are 8.7 million known species of organisms
• This is only 5% of all organisms that ever lived!!!!!
• New organisms are still being found and identified
Species of Organisms
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What is Classification?• Classification is the arrangement of
organisms into orderly groups based on their similarities (TRAITS)
• Classification is also known as taxonomy
• Taxonomists are scientists that identify & name organisms
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Early Taxonomists• 2000 years ago,
Aristotle was the first taxonomist
• Aristotle divided organisms into plants & animals
• He classified animals by the way they move… Land, sea or air.
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Early Taxonomists• Can you think of any
problems with this classification scheme?
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Early Taxonomists• John Ray, a botanist,
was the first to use Latin for naming
• His names were very long descriptions telling EVERYTHING about the plant (too long)
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Carolus Linnaeus1707 – 1778
• 18th century taxonomist
• Classified organisms by their structure
• Developed naming system still used today
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Carolus Linnaeus• Called the “Father of Taxonomy”• Developed the modern system of
naming known as binomial nomenclature
• Two-word name (Genus & species)
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Standardized Naming• RULES:
• Binomial nomenclature Genus species
• Latin or Greek
• Capitalize genus, but NOT species
• Italicized in print
• Underline when writing
Turdus migratorius
American Robin
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Binomial Nomenclature
Which TWO are more closely related?copyright cmassengale
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Rules for Naming Organisms
•The International Code for Binomial Nomenclature contains the rules for naming organisms
•All names must be approved by International Naming Congresses (International Zoological Congress)
•This prevents duplicated names
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Classification Groups• Taxon ( taxa-plural) is a category into
which related organisms are placed
• There is a hierarchy of groups (taxa) from broadest to most specific
• Kingdom, Phylum, Class, Order, Family, Genus, species
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Hierarchy-Taxonomic Groups
Domain Kingdom Phylum (Division – used for plants) Class Order Family
Genus Species
BROADEST TAXON
Most Specific
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King
Phillip
Can
Order
Family
Game
Saturdays!
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Kingdoms and Classification
If you had 10 minutes to buy milk and chips in a new grocery store, would you know where to look?
If the store has things classified, it makes it easier and faster to locate items
Classification is Everywhere
• Grocery stores classify items by type: baking items, dairy items, frozen food,
• Post offices classify mail by destination: zip code, then street, then house number
• Schools classify students by traits: grade number, gender, academic ability
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Benefits of Classifying• Accurately & uniformly names
organisms • Prevents misnomers such as starfish
& jellyfish that aren't really fish • Uses same language (Latin or some
Greek) for all names
Sea”horse”??
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Devil Cat
Ghost Cat
Mountain Lion
Screaming Cat
Puma
Florida Panther
Cougar
• There are at least 50 common names for the animal shown on the previous 7 slides.
• Common names vary according to region.
• Soooo……why use a scientific name?
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Confusion in Using Different Languages for Names
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Latin Names are Understood by all Taxonomists
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Felis concolor
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Latin Names are Understood by all Taxonomists
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• Using scientific names helps scientists communicate better and reduces confusion.
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Benefits of Classifying
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• Classification helps provide a better understanding of the relationships among living things.
Classificationgives clues
• Scientists have identified more than 8 million species of organisms on Earth
• Scientists group organisms based on similarities
• When organisms are arranged in groups, they are easier to study
• Classifying organisms into groups is called Taxonomy
What is a cassowary?• What does a cassowary look like?
• What does a cassowary eat?
• How big is a cassowary?
If you know that a cassowaryis classified as a bird, you also know
that…
• It has wings• It has feathers• It has hollow bones• It has a beak• It is probably an omnivore• It can be seen using only
the eyes• Classification clues us in
The History of Classification
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Scientists classify based on STRUCTURE
• The basic structure of an organism doesn’t change.
• What would happen if we classified organisms based on color?
• A zebra and a zebra fish would be cousins!
Aristotle had two kingdoms
Plants• Don’t Move• Green
Animals• Move around
After Careful observation…
• Fungi didn’t fit…• Can grow in the dark• Spring up overnight• Need dead things to
grow on• So a 3rd kingdom was
created for Fungi
A sampling of fungiMold Yeast
More examples of fungi
Truffles Mushrooms
This 3-kingdom system lasted for several hundred
years
• Until microscope technology allowed us to see smaller organisms
Most of what they saw in the microscope wouldn't fit into these
three kingdoms
• They could move like animals, but had only one cell
• They didn’t have to “mate” to reproduce Paramecium
So scientists created a fourth kingdom called Protista
• Single celled
• Live in water or very moist environments
• Most can move
• Some are photosynthetic
• Many are parasites
A sampling of protistsEuglena Giardia
More protists
algae amoeba
These 4 kingdoms were the only ones for a few years until microscopes
improved, and we could see inside single cells
• We noticed differences in nuclei
• Some organisms didn’t have a nucleus at all – only a single chromosome floating in the cytoplasm
• Initially all these small prokaryotic cells were grouped into Kingdom MONERA.
• Later, as we made more observations, another difference appeared. There are now two groups of bacteria, based on the composition of their cell walls.
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ARCHAEABACTERIA• Probably the 1st cells to evolve• Live in HARSH environments• Found in:– Sewage Treatment Plants
–Thermal or Volcanic Vents
–Hot Springs or Geysers that are acid
–Very salty water (Dead Sea; Great Salt Lake)
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ARCHAEAN
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EUBACTERIA• Some may cause DISEASE• Found in ALL HABITATS except
harsh ones• Important decomposers for
environment• Commercially important in making
cottage cheese, yogurt, buttermilk, etc.
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Live in the intestines of animals
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A sampling of Monerans
Strep bacteria Staph bacteria
More Monerans
E. coli bacteria Meningiococcal bacteria
Even more Monerans
Sleeping sickness pneumonia
Currently thereare 6 kingdoms
Animalia
Plantae
Fungi
Protista
Archaebacteria
Eubacteria
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Number of organisms
Some scientists even want to create a 7th kingdom for
virusesViruses aren’t technically alive because they can’t live without a host
A sampling of viruses
ebola influenza
More Viruses
cold H.I.V.
The better our technology becomes, the more we know
about organisms
We have a system for describing exactly where things fit…..TAXONOMY
Just like when you send a letter to Portugal, first you specify the country, then the city, then the street, then the building, then the floor number, then left or right, then the room number. Otherwise it would be impossible to find people.
So how do we know where to
put things in the classification
scheme?Remember, living things are classified on similarities in
structure.
First, start with the kingdom
A Snowy Owl belongs to the animal kingdom because
• it can move
• it is made of more than one cell
• it has to eat
Then, decide on the Phylum
A Snowy Owl belongs to the Chordata Phylum because
• It has a spinal cord
• It has bones
Then, decide on the Class
A Snowy Owl belongs to class Aves because
• It has a feathers
• It has a beak
• It lays eggs
Then decide on the Order
A Snowy Owl belongs to the order Strigiformes because
• It is a carnivore
• It has large, sharp talons
Then decide on the Family
A snowy owl belongs to the family Stringidae because
• It has a hooked beak
• It has a round face
• It hunts at night
Then decide on the genus,
A Snowy Owl belongs to the genus Bubo because
• It lives in the Northern Hemisphere
• It has a fourth talon
Then decide on the species
A Snowy Owl belongs to the scandiacus species because
• It is white
• It weighs about 40 grams
• It has dense downy feathers
The more classification levels that are shared by two organisms, the more alike they are.
A snowy owl is more like a barn owl than an sparrow.
If they are in the same species, they can
breed and produce offspring that can also
reproduce.
Scientific name = Genus species
Example: Homo sapiens = humans
Which of these are most closely related?
A Felis familiaris
B Canis familiaris
C Canis lupus
Which of these are most closely related?
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Eukaryotic Kingdoms
• Protista (protozoans, algae…)
• Fungi (mushrooms, yeasts …)
• Plantae (multicellular plants)
• Animalia (multicellular animals)
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Protista• Most are unicellular• Some are
multicellular• Some are
autotrophic, while others are heterotrophic
• Aquatic
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Fungi• Multicellular, except
yeast• Absorptive
heterotrophs (digest food outside their body and then absorb it)
• Cell walls made of chitin
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Plantae•Multicellular•Autotrophic•Absorb sunlight to make glucose – Photosynthesis•Cell walls made of cellulose
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Animalia• Multicellular• Ingestive
heterotrophs (consume food and digest it inside their bodies)
• Feed on plants or animals
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Taxons• Most genera contain a number of
similar species
• The genus Homo is an exception (only contains modern humans)
• Classification is based on evolutionary relationships
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Basis for Modern Taxonomy
• Homologous structures (same structure, different function)
• Similar embryo development
• Molecular Similarity in DNA, RNA, or amino acid sequence of Proteins
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xxx
• xxx
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Dichotomous Key• Used to identify organisms
• Characteristics given in pairs
• Read both characteristics and either go to another set of characteristics OR identify the organism
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Example of Dichotomous Key
1a Tentacles present – Go to 2
1b Tentacles absent – Go to 3
2a Eight Tentacles – Octopus
2b More than 8 tentacles – Go to 3
3a Tentacles hang down – Go to 4
3b Tentacles upright–Sea Anemone
4a Balloon-shaped body–Jellyfish
4b Body NOT balloon-shaped – Go to 5
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THE END………. Or is it?
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