Biology 14.1 Classification of Organisms
Classification
of
Organisms
Taxonomy
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Just as it is impossible for postal
workers to sort mail by only a
person’s name; it is impossible for
biologists to memorize every name of
the 10-30 million organisms on Earth.
To sort mail, a postal worker first
sorts by zip code, than by street
number, than by name.
In the same way, biologists sort
organisms into large categories, than
split those categories into other
categories, and continue sorting into
smaller and smaller more specialized
categories.
Taxonomy
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More than 2000 years ago, the
Greeks grouped plants and animals
according to their structural
similarities.
Later Greeks and Romans grouped
plants and animals into basic
categories such as oaks, dogs,
horses, birds, fish and so on.
Eventually each unit of classification
came to be called a genus; the Latin
word for “group”
Starting in the Middle Ages, genera
were named in Latin.
Taxonomy
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The science of naming and
classifying organisms is called
taxonomy.
Until the mid-1700s, biologists
named organisms by adding
descriptive phrases in Latin to the
name of the genus.
The name of the European honeybee
was Apis pubescens thorace
subgriseo abdomine fusco pedibus
posticic glabis untrinque margine
ciliatus.
These names became so long that
they become difficult to use and not
everyone used the same name. A
simpler solution needed to be
developed.
Taxonomy
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In the 1750s, a simpler solution was
developed by a Swedish biologist,
Carl Linnaeus.
Linnaeus developed a naming system
that used only two words for each
species; a system called binomial
nomenclature
This two part name system became
popular among scientists and is used
today under the title “scientific
name”.
The scientific name for the same
honeybee is Apis mellifera; much
shorter than the previous old system
and easier to remember.
Taxonomy
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The first word in the two-part name
of a scientific name is the genus.
A genus is a category of taxonomy
that contains similar species.
Organisms in a genus share similar
characteristics.
Genus Quercus
For example the genus Quercus is
composed of different kinds of oak
trees.
The second word in a scientific name
identifies one particular kind of
organism within the genus called a
species.
Quercus Palustris
Taxonomy
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The first letter of a genus name is
always CAPITALIZED and the first
letter of the species name is always
lowercase. A scientific name is also
always italicized or underlined.
For example: Quercus is the genus
name for oak trees
Genus Quercus
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Quercus rubra is the name for a red
oak.
Quercus phellos is the name for a
willow oak.
Quercus is the genus name ; phellos
and rubra are the species names
Quercus Palustris
Taxonomy
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The scientific name of an organism
gives biologists worldwide a way to
talk about the same animals while
using different languages. It is a
universal naming system.
The name given to a species must
conform to the rules established by
an international commission of
scientists,
Jason Bond, an ECU professor of
biology, has named a newly
discovered trapdoor spider,
Myrmekiaphila neilyoungi, after the
legendary rock star.
All scientific names must have two
Latin words or terms created
according to the rules of Latin
grammar.
To the right are newly discovered
species of spiders named for rockstars Neil Young and David Bowie
Heteropoda davidbowie
Classifying Organisms
Linnaeus worked out a system of
classifying plants and animals in
which an organism’s form and
structure are the basis for ranking.
The different groups that all organisms
fall into can be arranged by 8 levels.
Species are at the bottom. Remember
species are a group of similar
organisms that are capable of
interbreeding.
A member of a species can breed with
another member of the same
species.
Domain
Classifying Organisms
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All species are members of a
genus; a larger group that contains
many species similar to each other.
Remember that our 2 part scientific
name lists the genus than the
species.
For example, Parthera pardus is the
scientific name for a species of
panther.
Pardus is the species name and
panthera the genus name .
Similar genus are collected into a
family. The family Felidae at right
houses all varieties of felines (cats
large and small; housecats to lions)
Domain
Classifying Organisms
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The family of felines is part of a
larger order. An order has many
families in it.
The order in the example at right is
the order of carnivora which
contains carnivores (meat eaters)
An order always contains similar
families.
Domain
Classifying Organisms
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After order comes class. A class
has many different orders under it.
In the example at right; the class is
mammalia (mammels)
The order of carnivora is just one
of many orders that fall under the
class of mammalia
Domain
Classifying Organisms
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Classes with similar characteristics
are grouped together into a phylum.
The class of mammalia at right is
just one of the many classes that
make up the phylum of chordata
Domain
Classifying Organisms
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The next step up the ladder is the
kingdoms.
Many phylums that are similar are
grouped together into a kingdom.
In the example at right the phylum
chordata is just one of several
phylum in the kingdom of animalia
(animals)
Domain
Classifying Organisms
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Last, but not least, all kingdoms are
grouped together into a domain.
All living things are grouped into one
of three domains.
Two domains, Archaea and Bacteria,
are each composed of a single
kingdom of prokaryotes.
The third domain, Eukarya, contains
all four kingdoms of the eukaryotes.
Domain
Classifying Organisms
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In order to remember the 8
categories in order, it is useful to
memorize a phrase.
Do Kindly Pay Cash Or Furnish
Good Security is a helpful way to
remember the order of
1.
2.
3.
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5.
6.
7.
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Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Domain
Classifying Organisms
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Scientific names are powerful
because they tell us much about an
organism.
Each level of classification is based
upon characteristics shared by all
members of the classification.
For example; the order carnivora
contains all members that eat meat;
ie are carnivores.
The class mammalia contains all
members that are mammels.
The family felidae contains all
members that are felines (types of
cats ranging from housecats to lions)
Domain
Classifying Organisms
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For another example; let’s
look at the classification
of a common honeybee.
The honeybee’s scientific
name, Apis mellifera,
indicates it belongs to the
genus Apis and the
species name is mellifera.
Together they give us the
scientific name of the
genus-species combined.
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Genus: Apis- All members
of this genus are actually
honey bees, living alone or
in hives
Classifying Organisms
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Family: Apidae- Honey
bees are members of the
group Apidae because
they have a corbicula
(pollen basket) on the
outside of each hind
appendage.
Classifying Organisms
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Order: HymenopteraHoney bees are
members of the group
Hymenoptera because
they have
“membranous wings,
and their abdomen's
first segment is fused
with the last segment
of the thorax.
Classifying Organisms
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Class: Insecta- Honey
bees are members of the
Insecta because: they
don't have any muscles
past the first segment of
their antenna; they have
something called
Johnston's organ; and
they have an internal
structure inside the head
called a tentorium.
Classifying Organisms
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Phylum: ArthropodaHoney bees are
members of the
Arthropoda because
they have segmented
bodies and a jointed
exoskeleton.
Classifying Organisms
Kingdom: Animalia- Honey
bees are members of the
Animalia because they are,
multicellular, heterotrophic
and motile at some point in
life.
Domain: EukaryotaHoney bees are members
of the domain Eukaryota
because their cells have a
membrane-bound nucleus
Classifying Organisms
Do Kindly Pay Cash Or
Furnish Good Security
1.
2.
3.
4.
5.
6.
7.
8.
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species