Classification of Living Things
Taxonomy and Cladograms
What is Taxonomy?
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For millennia humans have created
different ways to describe the living
things on our planet.
At first our attempts to organize
and classify animals were simple
and based solely on their external
appearance.
We now use a more complex
system.
Why Do We Need to Classify Things?
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The main reason is that knowing
which species are related to each
other, and how closely they are
related, is very useful to the
Scientific community.
If you were trying to find out what
was wrong with a whale it would be
useful to know that it is a mammal
and not a fish.
Carolus Linnaeus
Carolus Linnaeus 1707 - 1778
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Every recognized species on Earth is
given a two-part scientific name. This
system is called "binomial nomenclature."
Carolus Linnaeus (1707–1778) introduced
the concept of binomial nomenclature in
his great work called Systema Naturae.
In this book, nature was divided into
three kingdoms: mineral, vegetable, and
animals.
Linnaeus also established five ranks:
class, order, genus, species, and variety.
Taxonomic Hierarchy
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A Taxonomic hierarchy is very
similar to a family tree.
Through it you can track how
closely related each species is to
each other.
Depending on how detailed you
wish to be, this can be a simple tree
chart, or a complex one (tolweb.org
is an example of a complex one).
Do Kings Play Chess On Fine Glass
Surfaces?
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This year you will be responsible to
remember the following taxonomic
hierarchy:
Domain (Do)
Kingdom (Kings)
Phylum (Play)
Class (Chess)
Order (On)
Family (Fine)
Genus (Glass)
Species (Surfaces)
So How Does It Work?
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Each level of the hierarchy has several
groups and these groups each have
specific characteristics required to be part
of them.
If we found a new living organism we
would compare its characteristics to these
groups to see where it fits.
If it was endothermic (warm blooded),
fed its young milk, had hair and gave live
birth we would probably classify it as a
mammal.
We Just Keep Learning
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Since Linnaeus we have continued
to add new groups to the taxonomic
hierarchy.
As we continue to learn and develop
new tools for investigation (like DNA
analyses) we often have to change
how we describe an organism from
a taxonomic point of view.
Chimpanzee vs. Lion
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Domain: Eukarya
Kingdom: Animalia
Phylum: Chordate
Class: Mammalia
Order: Primates
Family: Pongidae
Genus: Pan
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Species: troglodytes
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Domain: Eukarya
Kingdom: Animalia
Phylum: Chordate
Class: Mammalia
Order: Carnivora
Family: Felidae
Genus: Panthera
Species: leo
Comparative Taxonomy
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By comparing the Chimpanzee to the Lion
we can see that though they are very
different creatures, they have some key
things in common.
Both are animals with chordates
(vertebrates) and mammals.
Yet one is a primate (apes and monkeys)
and the other a carnivore (meat eaters).
Evolutionists use these similarities and
differences to determine the relationships
between species.
Broad to Specific
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Each level of the taxonomic tree
gets more and more specific.
Domain, Kingdom, Phylum and
Class are very large groups with
broad characteristics (we’re
mammals too).
But by the time you get to Genus
and Species the characteristics get
very specific. See the next slide.
Cheetah vs. Lion
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Domain: Eukarya
Kingdom: Animalia
Phylum: Chordate
Class: Mammalia
Order: Carnivora
Family: Felidae
Genus: Acinonyx
Species: jubatus
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Domain: Eukarya
Kingdom: Animalia
Phylum: Chordate
Class: Mammalia
Order: Carnivora
Family: Felidae
Genus: Panthera
Species: leo
Comparative Taxonomy 2
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As you can see the cheetah and lion
share more in common than the lion
and chimpanzee did.
Yet despite both being Felidae
(cats) they are each part of a
different Genus and a unique
species.
The Species level is very specific.
Scientific Names
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Each living creature on our planet
has been given a Scientific name in
Latin.
The Genus and Species of a
creature are combined to create the
Scientific name (thank you
Linnaeus).
Panthera leo – lion
Acinonyx jubatus - cheetah
Why Latin?
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Each living creature on the planet has
several names. A lion is known as a
leone in Italian and an ingonyama in
Zulu.
This could lead to confusion amongst our
world’s scientists.
Since Latin is a dead language, meaning
it will never change as it is not actively
spoken, scientists use it to name things.
This name means the same thing, no
matter where you are on Earth.
Cladograms
Cladograms
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Cladograms are tree-like charts that
generally show the evolutionary
relationships between different
creatures or taxonomic groups.
They can be drawn artistically,
simply, or extremely complexly
(tolweb.org).
Basic Cladogram for Great Apes
Orangutan Gorilla
Chimpanzee Bonobo
Human
Interpreting a Cladogram
Interpreting a Cladogram
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Some cladograms give extra details.
The one above showed that all three
creatures possessed a backbone as they
come after the trait.
However only the horse and human
shared the placenta characteristic.
Thus humans are more closely related to
horses than to fish in an evolutionary
sense.
Resources
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www.hawaii.edu
www.torontozoo.com
www.nationalzoo.si.edu
www.tolweb.org