Transcript Chapter 18 Classification

Classification
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Species of Organisms
•There are 13 billion known
species of organisms
•This is only 5% of all
organisms that ever lived!!!!!
•New organisms are still being
found and identified
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What is Classification?
Classification is the
arrangement of organisms into
orderly groups based on their
similarities
Classification is also known as
taxonomy
Taxonomists are scientists that
identify & name organisms
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Benefits of Classifying
•organisms
Accurately & uniformly names
•starfish
Prevents misnomers such as
& jellyfish that aren't
really fish
Uses same language (Latin or
some Greek) for all names
•
Sea”horse”??
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Confusion in Using Different
Languages for Names
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Latin Names are Understood by
all Taxonomists
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Early Taxonomists
•2000 years ago,
Aristotle was the
first taxonomist
Aristotle divided
organisms into
plants & animals
He subdivided
them by their
habitat ---land,
sea, or air dwellers
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Early Taxonomists
•John Ray, a
botanist, was
the first to
use Latin for
naming
His names
were very long
descriptions
telling
everything
about the plant
•
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Carolus Linnaeus
1707 – 1778
• 18th century
taxonomist
• Classified
•
organisms by
their structure
Developed
naming system
still used
today
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Carolus Linnaeus
•Called the “Father of
Taxonomy”
•Developed the modern
system of naming known
as binomial nomenclature
Two-word name (Genus &
species)
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Standardized Naming
•Binomial
nomenclature used
•Genus species
•Latin or Greek
•Italicized in print
•Capitalize genus,
but NOT species
•Underline when
Turdus migratorius
writing
American Robin
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Binomial Nomenclature
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Rules for Naming Organisms
• The International Code for
Binomial Nomenclature contains
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the rules for naming organisms
All names must be approved by
International Naming Congresses
(International Zoological
Congress)
This prevents duplicated names
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Classification Groups
• Taxon ( taxa-plural) is a
•
•
category into which related
organisms are placed
There is a hierarchy of groups
(taxa) from broadest to most
specific
Domain, Kingdom, Phylum, Class,
Order, Family, Genus, species
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Hierarchy-Taxonomic Groups
Domain
BROADEST TAXON
Kingdom
Phylum (Division used for plants)
Class
Order
Family
Genus
Species
Genus and species are the two names used to identify
specific organisms in the binomial system
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King
Phillip
Came
Over
For
Gooseberry
Soup!
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Dichotomous Keying
•Used to identify organisms
•Characteristics given in
pairs
•Read both characteristics
and either go to another
set of characteristics OR
identify the organism
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Example of Dichotomous Key
1a
1b
2a
2b
3a
3b
4a
4b
Tentacles present – Go to 2
Tentacles absent – Go to 3
Eight Tentacles – Octopus
More than 8 tentacles – 3
Tentacles hang down – go to 4
Tentacles upright–Sea Anemone
Balloon-shaped body–Jellyfish
Body NOT balloon-shaped - 5
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Domains
• Broadest, most inclusive taxon
• Three domains
• Archaea and Eubacteria are
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unicellular prokaryotes (no
nucleus or membrane-bound
organelles)
Eukarya are more complex and
have a nucleus and membranebound organelles
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Archaea live in harsh environments and may
represent the first cells to have evolved.
Sewage
treatment
plants, thermal
vents, etc.
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Eubacteria, some of which
cause human diseases, are
present in almost all habitats on
earth.
Live in the
intestines
of animals
Many bacteria are important
environmentally and commercially.
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Domain Eukarya is Divided
into Kingdoms
•Protista (protozoans,
algae…)
•Fungi (mushrooms, yeasts …)
•Plantae (multicellular plants)
•Animalia (multicellular
animals)
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•Most are
unicellular
•Some are
multicellular
•Some are
Protista
autotrophic, while
others are
heterotrophic
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Fungi
• Multicellular,
except yeast
• Absorptive
•
heterotrophs
(digest food
outside their
body & then
absorb it)
Cell walls
made of chitin
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Plantae
•Multicellular
•Autotrophic
•Absorb sunlight
to make glucose –
Photosynthesis
Cell walls made of
cellulose
•
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• Multicellular
• Ingestive
•
Animalia
heterotrophs
(consume food
& digest it
inside their
bodies)
Feed on plants
or animals
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Taxons
•Most genera contain a
number of similar species,
with the exception of Homo
that only contains modern
humans
Classification is based on
evolutionary relationships
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Basis for Modern Taxonomy
•Homologous structures (same
structure, different
function)
Similar embryo development
Similarity in DNA, RNA, or
amino acid sequence of
Proteins
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Homologous Structures show Similarities in mammals.
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Similarities in Vertebrate
Embryos
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Cladogram
Diagram showing how organisms are related
based on shared, derived characteristics
such as feathers, hair, or scales
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Primate
Cladogram
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