Transcript Modern Taxonomy - Warren Hills Regional School District

Taxonomy – the branch of biology
that names and groups organisms
according to their characteristics
and evolutionary history. (Holt)
Through taxonomy scientists
classify organisms and assign
each organism a universally
acceptable name. (Prentice Hall)
Scientists
Aristotle – over 2000
years ago, he developed
the first system of classification.
He divided all living
organisms into two
categories:
Plants and animals.
Aristotle’s Classification
Scheme
Plants were divided into three
groups: herbs with soft stems,
shrubs, and trees with
a single wood stem.
Animals were divided into
land dwellers, water dwellers
and air dwellers.
He devised a system
of grouping organisms
into hierarchical categories.
He used structure and form
of organisms (morphology)
to help classify them.
Linnaeus’s
Levels of
Classification
Linnaeus developed a system of
seven levels or “taxa” (singular =
taxon).
The levels are grouped from the
largest most inclusive group to the
smallest most exclusive group.
Seven Levels of Taxonomy:
DOMAIN
• 1- Kingdom
•
2- Phylum (or Division)
•
3- Class
•
4- Order
•
5- Family
•
6- Genus
•
7- Species
Scientific Names
Linnaeus also developed a system of naming
called Binomial Nomenclature in which the
species name of an organism is made up of two
parts: the genus name & the species
identifier.
• Example: Grizzly bear
(common name)
binomial nomenclature
= Ursus arctos
(usually in italics, first word capitalized.)
Why do scientists avoid using common
names when discussing organisms?
Common names can be confusing because
they may vary among languages and even
among regions in a single country.
Example: A cougar
• is a puma,
• is a mountain lion
• is a catamount
• is a ghost cat
Pyractomena borealis
(example of scientific name)
Common names: Lightning bugs
Glowworms, or Fireflies (They are not
really flies – they are beetles. Flies have one pair of
wings, while other winged insects have two or four
pairs of wings. When the name of an insect contains
the word fly, such as dragonfly, or firefly, they are not
flies.)
Examples of other Firefly Genera.
Lamprocera – brilliant and wax-colored
Microphotus – small light
Macrolampis – big light
Pyrogaster – fire stomach
Lampyris – glowworm
Pyropyma – fire butt
Sometimes different species can
share the same common name:
• United Kingdom: Buzzard = Hawk
• United States: Buzzard = Vulture
Other Examples:
• Humans =
Homo sapiens
• Lion =
Panthera leo
• House cat =
Felis domesticus
• Domesticated dog =
Canis familiaris
• Red Maple Tree =
Acer rubrum
Six Kingdom System:
• Archaebacteria = unicellular prokaryotes
(descended from & very similar to first cells)
• Eubacteria = unicellular prokaryotes
(most bacteria that affect you)
• Protists =
protozoans & algae
• Fungi = fungi
• Plantae = plants
• Anamalia = animals
Traditional classification relied primarily
on body characteristics.
Biologists now group organisms into categories
that represent lines of evolutionary descent,
as well as physical characteristics.
DNA analysis is an important tool
in classification science. It
can be used to show how
closely related organisms may be.