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Classification and
Kingdoms
Classification
1.
Scientists have identified more than 2 million
species of organisms on earth, but have
estimated that there are a total of 40 million
that actually inhabit the earth. So, how do we
classify new species that are discovered?
Purpose of a Classification System
1.
2.
Assign a single universal name to each
organism
Place organisms into groups that have real
biological meaning
Taxonomy
Field of biology that studies the classification of
organisms
Names and groups organisms according to their
characteristics and evolutionary history
A universal system is necessary to have clear
communication among scientists
1.
2.
3.
a)
Eliminates the use of common names and confusion
Classification History
Aristotle – 2,000 years ago
1.
a)
Grouped animals into Land Dwellers, Water
Dwellers, and Air Dwellers
i.
ii.
b)
What about caterpillars  butterflies? Where should
they be classified?
What about frogs?
Grouped plants into 3 categories, based on differences
in their stems.
Classification History
Carl Linnaeus – mid-1700’s
2.
“Father of Modern Taxonomy”
Developed a hierarchy that is the basis of Modern
Taxonomy
a)
b)
Hierarchy goes from broad to narrow
i.
c)
d)
Used morphology (form and structure) to classify
organisms
Developed a system of groups called TAXA
i.
e)
Categories in which related organisms are placed
First divided all organisms into 2 groups (kingdoms)
i.
ii.
Plantae
Animalia
•
What about bacteria? Fungi? Where do they fit?
Binomial Nomenclature
Seven levels of modern classification (Linnaeus
had five – K, C, O, G, S)
1.
a)
b)
c)
d)
e)
f)
g)
Kingdom
Phylum
Class
Order
Family
Genus
Species
Broadest – most inclusive
Narrowest – most exclusive
King Phillip Came Over For Grandma’s Soup
Binomial Nomenclature
Kingdom level is the largest/most general group. It is
the most INCLUSIVE group (includes the most
organisms).
Species level is the smallest/most specific level.
It identifies the specific organism.
It is the most EXCLUSIVE group (includes the fewest
organisms).
Binomial Nomenclature
a)
b)
c)
“Two-word naming”
Use the genus and species for scientific naming (genus
is written 1st, species written 2nd)
i.e., for humans: Homo sapiens (italics when typing,
underline when writing; always capitalize the genus
name, but never the species name)
Classification of the Grizzly Bear
Kingdom - Animalia
Phylum - Chordata
Class -
Mammalia
Order -
Carnivora
Family - Ursidae
Genus -
Ursus
Species – Horribilis
The scientific name… Ursus horribilis
Binomial Nomenclature
Why do we have Binomial Nomenclature?
England – robin
North America – robin
Erithacus rubicula
Turdus migratorius
E. rubicula
T. migratorius
B.N. avoids confusion - different animals with
same name
Binomial Nomenclature
Sand dollar
Seahorse
B.N. avoids confusion - Confusing names
Binomial Nomenclature
Puma, cougar, or mountain lion?
Felis concolor
B.N. avoids confusion - one animal with many
names
Binomial Nomenclature
Species
Two organisms are the same species if they can
breed and produce fertile offspring.
Felis
domesticus
Felis
domesticus
Felis
concolor
Which two are the same species?
Modern Phylogenetic Taxonomy
Phylogeny – the study of evolutionary relatedness
among various groups of organisms
Modern Phylogenetic Taxonomy
Considerations Modern Taxonomists Take to Yield
Reliable Information About an Organism’s
Phylogeny
1. Morphology
2. Chromosomal Characteristics
3. Nucleotide and Amino Acid Sequences –
Molecular Biology
4. Embryological Development
5. Fossil Record
Modern Phylogenetic Taxonomy
Systematic
1.
a)
Phylogenetic Tree
i.
Shows relationships thought to exist among groups of
organisms
??
Modern Phylogenetic Taxonomy
Modern Phylogenetic Taxonomy
Cladistic
2.
a)
Cladograms
i.
New system of phylogenetic classification, uses certain
features of organisms – DERIVED
CHARACTERISTICS
Modern Phylogenetic Taxonomy
Six-Kingdom System
Modern taxonomists recognize that many
organisms are neither plants nor animals, so
they use the six - kingdom system.
1.
a)
Kingdoms group organisms together that have
similarities in such fundamental characteristics
i.
ii.
iii.
Major cellular structure
Methods of obtaining nutrients
Metabolism
Six Kingdoms
Archaebacteria (“archae” – ancient)
1.
a)
b)
c)
d)
e)
May be directly descended from and very similar to
the first organisms on earth
Unicellular prokaryotes with distinctive cell walls
without peptidoglycan
Some are autotrophic, producing food by
chemosynthesis, while others are heterotrophic
Lives in harsh environments such as sulfurous hot
springs, very salty lakes, and in anaerobic
environments
Include chemosynthetic bacteria
Six Kingdoms
Eubacteria (“eu” – true)
2.
a)
b)
c)
d)
Unicellular prokaryotes
Have cell walls made of peptidoglycan
Both autotrophs and heterotrophs
Include disease-causing bacteria that cause ailments
like tooth decay.
Six Kingdoms
Monerans – original name of both Archaebacteria
and Eubacteria.
•
•
These combined kingdoms have the greatest number
of organisms on earth.
Both reproduce by binary fissions, but do have some
ways of recombining genetic information  allowing
for evolution
Six Kingdoms
Protista (“ash and trash” kingdom)
3.
a)
b)
c)
d)
All eukaryotes that are NOT plant, animal, or fungi
Have cell walls; some have chloroplasts
Unicellular, and some Multicellular
Include Euglena and amoebas
Six Kingdoms
Fungi
4.
a)
b)
c)
d)
e)
Multicellular eukaryotes
Have cell walls that contain chitin
Heterotrophic and obtain their nutrients by releasing
digestive enzymes into a food source
Act either as decomposers or as parasites in nature.
Includes molds, mildews, mushrooms, and yeast.
Six Kingdoms
Plantae
5.
a)
b)
c)
d)
e)
Multicellular eukaryotes
Most are autotrophic
Have cell walls that contain cellulose.
Cells are specialized for specific functions, such as
photosynthesis, transport of materials, and support.
Includes mosses, ferns, cone-bearing plants
(gymosperms) and flowering plants (angiosperms)
Six Kingdoms
Animalia
6.
a)
b)
c)
d)
e)
Multicellular eukaryotes
Heterotrophic
No cell walls
Are mobile, but some are permanently attached to
surfaces (sponges and barnacles)
Includes fish, birds, reptiles, amphibians, mammals,
sponges, jellyfish, worms, sea stars, insects
Six Kingdoms
Domains
Used to group kingdoms together
3 Domains
1.
2.
a)
Bacteria
i.
b)
Archae
i.
c)
Composed of prokaryotic-celled organisms
Composed of prokaryotic-celled organisms
Eukarya
i.
Composed of eukaryotic-celled organisms
Domains
Domains