Explain why and how organisms are classified.
List the eight levels of classification.
Explain scientific names.
Describe how dichotomous keys help in
The classification of living things makes it
easier for biologist to answer many important
questions such as:
How many known species are there?
What are the defining characteristics of each
What are the relationships between these
HISTORY OF CLASSIFICATION
Taxonomy: science of describing, naming, and
HOW DO SCIENTISTS
Taxonomists use the eight-level system to
classify living things based on shared
On a branching diagram, several
characteristics are listed along the line that
points to the right. Each characteristic is
shared by the organisms to the right of it.
The eight levels of classification are:
A scientific name is always the same for a
specific kind of organism no matter how many
common names there might be.
Ex: Mountain lion, puma, cougar, panther are
all the Puma concolor
The first part of a species' name is the genus
name which is always capitalized. The second
part of the name is the species name.
A dichotomous key is a tool for identifying
organisms that uses a series of paired
By working through the statements in a
dichotomous key in order, a person can
eventually identify an unknown organism.
A GROWING SYSTEM
People are still discovering and classifying
Sometimes new organisms are found that are
so different from other known organisms that
new classes, phyla, and so on must be
Why do scientists classify organisms?
What are the eight levels of classification?
How does a dichotomous key help scientists
List seven musical artists or bands.
Categorize the names on your list by style of
Describe in your notebook the categories you
chose and explain which bands might fit into
more than one category.
Explain how classification developed as
greater numbers of organisms became
Describe the three domains.
Describe four kingdoms in the domain
WHAT IS IT?
Organisms are classified by their
As scientists continue to learn about living
things, they add classification categories that
account for the characteristics of different
ARCHAEA AND BACTERIA
Archaea are one of two kinds of prokaryotes.
Prokaryotes are single-celled organisms that
do not have a nucleus. Most are known to
live in extreme environments.
Bacteria are another kind of prokaryote but
they usually have a cell wall. Bacteria can be
found in soil, water, and even on and inside
the human body.
Today members of the kingdom Protista
commonly called protists, are single-celled or
simple multicellular organisms.
Protista contains many kinds of organisms,
including protozoans, algae, and euglenoids.
Molds and mushrooms are examples of the
complex, multicellular members of the
Fungi do not perform photosynthesis or eat
food. Instead, fungi absorb nutrients from
substances in their surroundings.
The kingdom Plantae consists of organisms
that are eukaryotic, have cell walls, and make
food through photosynthesis.
Examples: Sequoia trees, roses, grasses, ferns,
The kingdom Animalia contains complex,
multicellular organisms that don’t have cell
walls, are usually able to move around, and
have specialized sense organs.
Examples : Ants, beetles, lizards, fish, birds,
apes, elephants, and more
Most animals are able to move, but sponges,
a simple animal, cannot move.
What are the characteristics of each of the
What are the four kingdoms of the domain