Download Taxonomy and Binomial Nomenclature

Taxonomy and
Binomial Nomenclature
Biology
Post Falls High School
Why Classify?
• To name organisms
• This is binomial nomenclature
• To place them in logical relationships
– Separate by differences
– Group by similarities
• This is taxonomy
Why give scientific names?
• Many different organisms may share a
common name
– Buzzard = hawk (England) or vulture (U.S.)
– Gopher = rodent in West, turtle in S.E.
Why give scientific names?
• Many organisms have more than one
common name
– Mt. lion, puma, cougar
– Moose, hirvi
Beginnings of Classification
• Aristotle (384-322 BC) classified all living
things he knew
• Plant or Animal
• Organized Plants into herb, shrub, or tree
according to size and structure
• Organized Animals by habitat and physical
differences
– Birds, bats, and some insects grouped
together because they all have wings and fly!
Binomial Nomenclature
• To avoid confusion each has 2 part
scientific name
• Genus name + specific epithet (species
name); genus capitalized/species not
• Species name is often descriptive
• Written in italics (or underlined)
• In Latin
– Dead language
– Never changes in meaning
Red legged grasshopper
Melanoplus femur-rubrum
Father of Modern Taxonomy
Carolus Linnaeus
(Carl von Linne)
• born on May 23, 1707, in the province of
Småland in southern Sweden
• University of Uppsala, finished his medical
degree at the University of Harderwijk
• training in botany was part of the medical
curriculum, for every doctor had to prepare
and prescribe drugs derived from
medicinal plants
Carolus Linnaeus
(Carl von Linne)
• published the first edition of his
classification of living things, the Systema
Naturae
• professorship at Uppsala in 1741, he
restored the University's botanical garden
(arranging the plants according to his
system of classification)
• died in 1778
Linnaean Classification
• Hierarchical with 7 levels, or taxa (taxonsingular)
• Kingdom, phylum (division in plants),
class, order, family, genus, species
American
Lobster
Market
Squid
Blue
Mussel
Virginia
Oyster
European
Oyster
Phylum
Arthropoda
Mollusca
Mollusca
Mollusca
Mollusca
Class
Malacostraca
Cephalopoda
Bivalvia
Bivalvia
Bivalvia
Order
Decapoda
Decapoda
Mytiloida
Pterioida
Pterioida
Family
Nephropidae
Loliginidae
Mytilidae
Ostreidae
Ostreidae
Genus
Homarus
Loligo
Mytilus
Crassostrea
Ostrea
Species
americanus
opalescens
edulis
virginica
edulis
Value of Taxonomy
• 1. Taxonomy works out for us a vivid picture
of the existing organic diversity of the earth.
2. Taxonomy provides much of the
information permitting a reconstruction of
the phylogeny of life.
3. Taxonomy reveals numerous interesting
evolutionary phenomena.
4. Taxonomy supplies classifications which
are of great explanatory value in most
branches of biology and paleontology.
• 5. Taxonomy organizes known lifeforms.
Alterations to Taxonomy
• Biologists now group organisms into
categories that represent lines of
evolutionary descent, or phylogeny, not
just physical/chemical similarities
• This means similar genes and DNA is a
strong contributor in modern taxonomic
decisions
• Ex. American vulture, African vulture, and
stork
Cladogram
• Identifies and considers only those
characteristics that are evolutionary
innovations (new traits that arise as
species change over time)
• New traits in later members of lineage
called derived characteristics
• Used to construct cladogram, a diagram
that shows evolutionary relationships
Cladogram
Cladogram
Molecular Clock
• Accumulation of neutral mutations after
separation of relatives
• Dissimilarity in DNA sequences can be
used to calculate time since separation
Kingdoms
•
•
•
•
•
2 (Plantae/Animalia) for Aristotle/Linnaeus
Then came Protista for microscopic
Then came Fungi for odd plants
Then prokaryotes became Monera
5 kingdoms !
Kingdoms
• Now Monera has been subdivided
• Now there are 6!
– Archaebacteria for the older, primitive bacteria
– Eubacteria for the “true” modern bacteria
Determination of Evolutionary
Relationships
•
•
•
•
•
Structural similarities
Breeding behavior
Geographical distribution
Chromosome comparison
Biochemistry
Domains
• Now scientists have devised supergroups
to place these related kingdoms
• Eukarya – protists, fungi, plants, animals
• Bacteria – the true bacteria
• Archaea – primitive forms of bacteria
Bacteria
• Unicellular prokaryotes
• Thick, rigid cell walls surrounding a
membrane
• Peptidoglycan in walls
Archaea
• Unicellular prokaryotes
• Live in extreme environments and are all
anaerobic
• Walls lack peptidoglycan and membranes
consist of unusual lipid structure
Eukarya
• All eukaryotes (with nuclei)
• All the rest of organisms known to man
• Without a set of international rules to follow, the results of
taxonomy would be confusing at best. The rules of zoological
nomenclature are contained in a document known as the
International Code of Zoological Nomenclature (ICZN). The
object of the code is to promote stability and universality in the
scientific names of animals. All names must be unique,
universal, and show stability.
Uniqueness Every name has to be unique. If several names
have been given to the same taxon, priority decides which
name will be the valid name.
Universality Zoologists have adopted, by international
agreement, a single language to be used on a worldwide basis.
All animals are given a generic and specific name in Latin.
These names are in italics or are underlined (i.e. Homo
sapiens).
Stability The ICZN attempts to prevent the frequent changing
of names to provide stability.