Transcript Classification Notes - Valhalla High School

Classification Notes
Taxonomy
• Naming and grouping
organisms according
to their characteristics
and evolutionary
history.
Aristotle
• Greek philosopher
who first attempted to
classify living
organisms
• Over 2000 years ago
Aristotle
• He classified living
things into two
groups:
– Plants
– Animals
Aristotle
• Why did his system
create problems?
– Not all living things are
plants and animals
– Even plants and
animals are very
diverse
– Our knowledge of life
has changed
Carolus Linnaeus
• Swedish scientist who
developed our
modern system of
classification.
• 1707 - 1778
Carolus Linnaeus
• Used morphology
(form and structure)
to categorize
organisms
Carolus Linnaeus
• Developed a hierarchy of levels in his
system
– Kingdom
– Phylum
– Class
– Order
– Family
– Genus
– Species
King
Phillip
Came
Over
For
Good
Soup
Species
• Remember that a species is a group of
organisms that can mate and reproduce
fertile offspring
• Not a clear cut definition
Common Names
• Most people use
common names for
organisms
• This causes problems
– 13 lined ground
squirrels are often
called gophers
Scientific Names
• Scientific names
solve the naming
problem
• Latin is used for most
scientific names.
Binomial Nomenclature
All organisms are
given a genus and a
species name.
This way all people
can use the same
name to identify
organisms
Genus and Species
• The genus name
comes first and
begins with a capital
letter.
– Ex. Felis (it can be
abbreviated as F.
• The species names
comes second and
begins with a lower
case letter.
– Ex. domesticus
*Both the genus and species
names are usually italicized and
often underlined.
Ex. Felis domesticus
How do we classify organisms
today?
• Not so much on
physical similarities
(can be based too
much on opinions).
• Scientific evidence is
a better way to do
this.
Evidence for Classification
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Chromosome Structure
Biochemical Similarities
Embryology
DNA Sequencing
Reproduction
Systems of Classification
• Linnaeus used 2
Kingdoms
– Plant
– Animal
The Three-Domain System
The Three-Domain System
Molecular analyses have given rise to a new
taxonomic category that is now recognized by
many scientists.
The domain is a more inclusive category than any
other — larger than a kingdom.
Copyright Pearson Prentice Hall
The Three-Domain System
The three domains are:
• Eukarya, which is composed of protists, fungi, plants,
and animals.
• Bacteria, which corresponds to the kingdom
Eubacteria.
• Archaea, which corresponds to the kingdom
Archaebacteria.
Copyright Pearson Prentice Hall
Domain Bacteria
Domain Bacteria
Members of the domain Bacteria are unicellular
prokaryotes.
Their cells have thick, rigid cell walls that surround a
cell membrane.
Their cell walls contain peptidoglycan.
Copyright Pearson Prentice Hall
Domain Archaea
Domain Archaea
Members of the domain Archaea are unicellular
prokaryotes.
Many live in extreme environments.
Their cell walls lack peptidoglycan, and their cell
membranes contain unusual lipids not found in any
other organism.
Copyright Pearson Prentice Hall
Domain Eukarya
Domain Eukarya
The domain Eukarya consists of organisms that
have a nucleus.
This domain is organized into four kingdoms:
–
–
–
–
Protista
Fungi
Plantae
Animalia
Copyright Pearson Prentice Hall
Modern Kingdoms
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Animalia
Plantae
Fungi
Protista
Archaebacteria
Eubacteria
Animalia
• Multicellular heterotrophs
Plantae
• Multicellular autotrophs
Fungi
• Most are multicellular
• Yeast is unicellular
• Absorb food through
cell walls
Archaebacteria
• Unicellular
prokaryotes
• Related to first life
forms
• Live in harsh
environments
Eubacteria
• Unicellular
prokaryotes
• Includes most
bacteria
Classification of a human
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Kingdom = Animalia
Phylum = Chordata
Class = Mammalia
Order = Primate
Family = Hominid
Genus = Homo
Species = sapien