CLASSIFICATION
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Species of Organisms
• 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
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What is Classification?
•
•
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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
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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 Linnaeus
1707 – 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:
Turdus migratorius
• Binomial nomenclature
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Genus species
Latin or Greek
Capitalize genus, but
NOT species
Italicized in print
Underline when writing
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American Robin
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Binomial Nomenclature
Which TWO are more closely related?
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Rules for Naming
Organisms
• The International Code for Binomial
•
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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
BROADEST TAXON
Domain
Kingdom
Phylum (Division – used for plants)
Class
Order
Family
Genus
Most
Species
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
Benefits of Classifying
• Accurately & uniformly names
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•
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
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•
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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?
Confusion in Using Different
Languages for Names
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Latin Names are Understood
by all Taxonomists
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Felis
concolor
Latin Names are
Understood by all
Taxonomists
• Using scientific names helps
scientists communicate better and
reduces confusion.
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Benefits of Classifying
• Classification helps provide a
better understanding of the
relationships among living
things.
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Classification
gives clues
• Scientists have identified more than 8
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•
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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 cassowary
is classified as a bird, you also
know that…
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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 fungi
Mold
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
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•
Paramecium
They could move
like animals, but
had only one cell
They didn’t have
to “mate” to
reproduce
So scientists created a fourth
kingdom called Protista
• Single celled
• Live in water or very
•
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moist environments
Most can move
Some are
photosynthetic
Many are parasites
A sampling of protists
Euglena
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
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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 there
are 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 viruses
Viruses 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?
Eukaryotic Kingdoms
• Protista (protozoans, algae…)
• Fungi (mushrooms, yeasts …)
• Plantae (multicellular plants)
• Animalia (multicellular animals)
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Protista
• Most are unicellular
• Some are
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•
multicellular
Some are
autotrophic, while
others are
heterotrophic
Aquatic
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Fungi
• Multicellular, except
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•
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
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heterotrophs
(consume food and
digest it inside their
bodies)
Feed on plants or
animals
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Taxons
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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
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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……….
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or is it?
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