Notes: Classification
Notes: Classification of
Living Things

For more than 3.5 billion years, life on
Earth has been constantly changing.
Natural selection and other processes
have lead to a staggering diversity of
organisms. Biologists have identified
and named about 1.5 million different
organisms so far (with many more that
have yet to be discovered)
How do we define what is
alive? Living things share the
following characteristics of
life…

All living things:
Made of Cells
 Reproduce
 Based on a universal genetic code (DNA)
 Grow and develop
 Obtain and use energy
 Respond to environment
 Maintain homeostasis
 Change over time


Today, we classify
all living organisms
based upon a
system that was
developed over 200
years ago by a
Swedish botanist
named Carolus
Linnaeus.

Linnaeus created a system of naming
all living things called binomial
nomenclature.
– According to this system, each organism
should be given a two-word name, called
a scientific name.

The same name is
used regardless of the
language that a person
speaks or the region
they live in.
– This also helps avoid the
problems with common
names that may change
based upon the region
that individuals live in
(i.e. mountain lion,
cougar and Florida
panther are all the same
species found in various
places in the US)

Most names are in Latin (so they sound
different than our words)
– The first word of each name is called the genus.
The first letter of this name should always be
capitalized.
– The second word of each name is the species
identifier. This name should always be in
lower case.
Ex. The scientific name for humans is Homo sapiens
(Genus + species)
….notice it is written in italic print


Similar organisms that may be the
same genus but not the same species
can sometimes reproduce under
artificial conditions. However, their
offspring often end up being sterile.
Two examples of interbreeding two
different species are…
..add this to your notes! 


Species: A group of organisms that
can successfully interbreed to produce
offspring that can also interbreed.
i.e: they can produce children that can
continue to produce children.
Horse
Donkey
Horse
Donkey
+
Mule

Mule x Mule= no offspring
Lion
Tiger
Lion
+
Tiger
Liger
Linnaeus’ original classification
system was made up of 7 levels
called Taxa:
Complete the following table as we go
through the notes.
Linnaeus’s taxa
(largest to smallest)
Bobcat Classification
Lynx Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Animalia
Chordata
Mammalia
Carnivora
Felidae
Lynx
Lynx rufus
Animalia
Chordata
Mammalia
Carnivora
Felidae
Lynx
Lynx candensis
Words to Know:
Taxon: a single taxonomic group.
Taxa: more than one taxonomic group.
Taxonomy: study of classifying living
things
Taxonomist: scientist who studies
classification

What is the
scientific name for
the Lynx?
– Lynx candensis

Which is more closely related to the
lynx, the Leopard (Panthera pardus) or
the Bobcat (Lynx rufus)?
Leopard
Bobcat

The Bobcat because they are in the same genus.
Lynx
Bobcat

In the original classification system it was
thought that all living organisms could be
grouped into one of the two kingdoms:
– The Plant Kingdom or the Animal Kingdom
– Why might it have been necessary to create
more than two kingdoms?

Not everything can be grouped into those two
kingdoms.
Table 1: Changing Number of Kingdoms
Plantae
Original
Division
(written
in latin)
19501990
TODAY
Monera (all bacteria)
Eubacteria
Arachaebacteria
Animalia
Protista
Fungi
Plantae
Animalia
Protista
Fungi
Plantae
Animalia

Domain- a new level that (is larger
than a kingdom) has been added to
the current classification system.
Based on new research, all iving things
in the six kingdoms were placed into
one of the 3 Domains:



Domain Bacteria- includes all of kingdom
Eubacteria (also known as ‘true bacteria’)
Domain Archaea- includes all of kingdom
Arachaebacteria (also known as ‘ancient
bacteria’)
Domain Eukarya- includes the kingdoms
Protista, Fungi, Plantae and Anamalia
(all of which are eukaryotes)
Fill in the correct taxa for the
new (current) structure of the
classification system:
Species
Genus
Family
Order
Class
Phylum
Kingdom
Domain