Taxonomy
taxonomy…
• the classification of an organism (anything
that is alive) based on structure, behavior,
development, genetic makeup (DNA),
nutritional needs and methods of obtaining
food.
• divides organisms into several categories that
start out broadly but become more specific.
• Kingdom, Phylum, Class, Order, Family, Genus,
and Species.
The Six Kingdoms
• Until the discovery of chemosynthesizers,
there were five kingdoms – monera, protista,
fungi, plantae, and animalia.
• Today there are six recognized kingdoms that
encompass every living thing known to man –
archaebacteria, monera, protista, fungi,
plantae, and animalia.
• Which kingdom are human part of?
…levels of classification…
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Kingdom – based on general characteristics.
Phylum – does it have a backbone?
Class – is it a mammal or an insect?
Order – even more specific than class.
Family – usually ends in “idae” or “idea”.
Genus – very specific; members of same genus
can often breed but offspring are infertile.
• Species – most specific; organisms of the same
species are grouped base on the ability to breed
and produce fertile offspring.
kingdom → phylum → class →
order → family → genus → species
“King Phillip Came Over From
Greece Sneezing”
Carl Linnaeus
(1707 – 1778)
Swedish botanist that
devised current
classification system.
Used binomial
nomenclature, a system for
naming organisms using a
two-part name to label the
species.
Written in Latin.
Consists of genus and
species.
The entire scientific name is
italicized or underlined, and
genus name is capitalized.
Ex) Homo sapiens
• Animalia
• Chordata
• Mammalia
• Primate
• Homindae
• Homo
• sapiens
Why use Latin names?
• Latin is one of the oldest languages on Earth.
• Many other languages are derived from Latin.
• No matter what country a person lives in, or
what language they speak, they will always
know what organism is being referenced by
its’ Genus species Latin name.
Limitations of hierarchical classification…
• Doesn’t take evolution into consideration.
• Doesn’t take into account the variation that
exists among individuals within a species.
Ex) all domestic dogs are called Canis lupus
familiaris, but much variation exists among
different breeds of dogs and even among
individual dogs of the same breed.
The “True Test”?
• Organisms of the same species can breed
successfully, producing “fertile” offspring.
• Fertile – the ability to breed/reproduce.
• However, sometimes closely related species
can interbreed, such as the mating of a horse
and donkey to produce a mule; a lion and a
tiger to produce a liger; a dolphin and whale
to produce a wolphin. In these situations, the
offspring are sterile, or unable to reproduce.
Species crosses…
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What if you encounter a
species, and you don’t
know what it is?
•Identifying biological organisms
can be performed using a
dichotomous key.
•A dichotomous key is an
organized set of questions, each
with yes or no answers.
•Each question addresses a
characteristic of the organism.
How you answer determines
which question you answer next.
•The key starts with general
questions and becomes
progressively specific.
•By following the key and making
the correct choices, you should be
able to ID your specimen to the
indicated taxonomic level.
•Works for ALL known organisms.
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Create a dichotomous key using the following list of specimens: pine
tree, clam, rock,
robin, tin can, deer, oak tree, mouse, dandelion, Paramecium, bicycle,
ant
Here's an example in written form using these items:
1. a. Organism is living........................................................go to 4.
1. b. Organism is nonliving..................................................go to 2.
2. a. Object is metallic........................................................go to 3.
2. b. Object is nonmetallic..................................................ROCK.
3. a. Object has wheels......................................................BICYCLE.
3. b. Object does not have wheels......................................TIN CAN.
4. a. Organism is microscopic...................................PARAMECIUM.
4. b. Organism is macroscopic............................................go to 5.
5. a. Organism is a plant.....................................................go to 6.
5. b. Organism is an animal.................................................go to 8.
6. a. Plant has a woody stem..............................................go to 7.
6. b. Plant has a herbaceous stem.................................DANDELION.
7. a. Tree has needle like leaves.....................................PINE TREE.
7. b. Tree has broad leaves............................................OAK TREE.
8. a. Organism lives on land................................................go to 9.
8. b. Organism lives in water...............................................CLAM.
9. a. Organism has 4 legs or fewer......................................go to 10.
9. b. Organism has more than 4 legs...................................ANT.
10 a. Organism has fur........................................................go to 11.
10 b. Organism has feathers................................................ROBIN.
11 a. Organism has hooves.................................................DEER.
11 b. Organism has no hooves............................................MOUSE.
Review…
• Taxonomy is the classification of organisms based on
common and differing characteristics.
• The levels of classification are kingdom, phylum, class, order,
family, genus, and species.
• The modern classification system is based on work done by
Carl Linnaeus.
• Organisms that are the same species can reproduce and
have fertile offspring.
• Some organisms of the same family can breed; however,
their offspring will be infertile, or sterile.
• A dichotomous key is used to identify unknown organisms
by answering a series of “yes/no” questions.
• Latin is the language used in classification because it is
common in the scientific community.