History of TAXONOMY
STATE GOAL 13.A.3b Analyze historical and contemporary cases in which the work of
science has been affected by both valid and biased scientific practices.
Essential Question:
***What is taxonomy and why is it needed?***
The evolution of life on Earth over the past 4 billion years has
resulted in a huge variety of species. In fact, there are literally
millions and millions of different species. For more than 2,000
years, humans have been trying to classify this
great diversity of life. The science of classifying
organisms is called taxonomy. In Taxonomy
organisms are grouped according to common
characteristics. An organism is any living
thing.
Scientists who study taxonomy are called
taxonomists. The Greek scientist, Aristotle
(384-322 B.C.), was one of the first scientists
to organize living things, thus among other things he studied,
Aristotle was a taxonomist.
Aristotle developed the first classification system, which
divided all known organisms into two groups: PLANTS and
ANIMALS
Aristotle then divided each of these
main groups into three smaller groups.
Animal Subgroups: Land, Water, Air
Plant Subgroups: Small, Medium, Large
Aristotle’s classification system was not
very good. There were too many
organisms that didn’t fit. For example,
frogs are born in water and have gills
like fish, but when they grow up they
have lungs and can live on land. So
how would Aristotle classify frogs? In Aristotle’s classification
system, birds, bats, and flying insects were grouped together
even though they have little in common except they can fly. But
the penguin is a bird that cannot fly. So Aristotle would not have
classified them as birds.
Even with the many problems of Aristotle’s limited classification
system, it was used for nearly 2000 years.
Then in the 1750’s it was replaced by the Swedish biologist,
Carolus Linnaeus (1707-1778).
Linnaeus, like Aristotle,
classified organisms according
to their traits. The classification
systems of both Aristotle and
Linnaeus started with the same
two groups: Plants and
Animals.
Linnaeus called these groups
kingdoms. But, unlike Aristotle,
Linnaeus divided the kingdoms into 4 more levels: class, order,
genus, and species. Kingdom was divided into smaller groups
called classes. Each class was split into orders. Each order was
divided into genus and each genus into many species. Organisms
were placed in these levels based on traits, including similarities
of body parts, physical form such as size, shape, and
methods of getting food.
In addition to expanding the classification system, Linnaeus
established a simple way of naming each species. This is called
binomial nomenclature and is a naming system with two
parts. The first part of the species name identifies the genus;
the second part identifies the species. For example, humans
belong to the genus Homo and to the species sapien. Thus, the
two-part species name for humans is Homo sapien. The genus
name is capitalized and each name is written in italics. For
expanding the classification system and for creating a naming
system, Linnaeus is known as the father of taxonomy.
Today, Linnaeus basic structure is still used; however, some
other divisions have been added.
(Pg. 43) Today the taxonomy order used from largest grouping
to smallest grouping is as follows:
LEVELS OF CLASSIFICATION:
LARGEST TO SMALLEST GROUP
Domain
Example using Humans:
DOMAIN: Eukaryota *
Kingdom
KINGDOM: Animalia
Phylum
Class
PHYLUM: Chordata
EXAMPLE
CLASS: Mammalia
Order
ORDER: Primata
Family
FAMILY: Hominidae
Genus
GENUS: Homo
Species
SPECIES: Homo Sapien
*Eukaryotes have a
Nucleus in their cells!
Here is a Mnemonic Device to help you in remembering
taxonomy order from largest to smallest group:
Dumb King Phillip Could Only
Find Green Socks!
Domain-Kingdom-Phylum-Class-Order-Genus-Species
Name ___________________
Period # _______________
History of Taxonomy Homework
Date _________________
Look back in the reading and write definitions for:
1. Taxonomy -
2. Organism –
3. Which scientist developed the FIRST system of organization
in which organisms were divided into 2 main groups? ______
4. These 2 main groups of organisms were __________ &
________________
5. In the space below, complete the diagram to show the first
system of classification:
Animal Subgroup
_________ Subgroup
1. Land Animals
1. _______
2. ________ Animals
2. Medium
3. _______ Animals
3. _________
6. Explain why the system of classification shown above is not
very good and give an example:
7. In the 1750’s this classification system was replaced by a
system developed by Carolus Linneaus. His system also divided
organisms into Plants & Animals. How did Linneaus’
classification system DIFFER from Aristotle’s?
8. Linnaeus developed a 2 part naming system for each
species. This system is called _____________
_______________________.
9. For example; humans are Homo sapiens.
Using this system, humans belong to the GENUS ___________
& the SPECIES ____________
To answer the next question requires you to do some critical thinking.
The answer is NOT in the reading!!
10. HIGH LEVEL OF REASONING = EVALUATING
You are a taxonomist! A fellow scientist approaches you and says
that classifying organisms into groups is a waste of scientific time.
You disagree!
What 2 arguments would you use to defend the practice of
classification in Science?
(Your answer may take the form of: a bulleted list, a concept web,
thought bubbles or written paragraph.