Transcript Chapter 18 Classification

Classification
Chapter 17
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Species of Organisms
•Almost 2 million species of
organisms have been described
•Thousands more are discovered
each year
•The total number of species
ranges from 5 to 30 million
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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 --
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•
Ex) land, sea, or air dwellers
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Carolus Linnaeus
1707 – 1778
• 18th century
taxonomist
• Classified organisms by
•
•
their form and
structure
Developed 7 levels of
classification
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 nomenclaturetwo-word name (Genus &
species)
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Standardized Naming
Binomial nomenclature
uses:
•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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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
BROADEST TAXON
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
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King
Phillip
Came
Over
For
Good
Spaghetti!
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Two Modern Systems
Six Kingdom System
Three Domain System
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The Six Kingdoms:
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KingdomArchaebacteria
•The prefix archae - comes from the Greek
word "ANCIENT"
•Unicellular & Prokaryotic
•Some are autotrophic and some are
heterotrophic
•Live in extreme environments
Sewage
treatment
plants, thermal
vents, etc.
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Kingdom Eubacteria
•Cause human
diseases, are present
in almost all habitats
on earth
•Many bacteria are
important
environmentally and
commercially.
Live in the
intestines
of animals
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Kingdom Protista
“The odds and
ends kingdom”
Dumping ground
of organisms that
don’t fit into the
other kingdoms
Eukaryotic
Unicellular or
Multicellular
Ex) Algae, Slime molds, Diatoms,
and Protozoa
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Kingdom Fungi
• Multicellular,
except yeast
• Absorptive
•
heterotrophs
(digest food
outside their body
& then absorb it)
Decomposers
Ex) yeast, mold,
mildew, &
mushrooms
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Kingdom Plantae
•Multicellular
•Autotrophic
•Absorb sunlight
to make glucose –
Photosynthesis
Cell walls made of
cellulose
•
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Kingdom Animalia
• Multicellular
• Ingestive
•
heterotrophs
(consume food
& digest it
inside their
bodies)
Feed on plants
or animals
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Domains
• Broadest, most inclusive taxon
Three domains:
1.Archaea
2.Eubacteria are unicellular
prokaryotes (no nucleus or
membrane-bound organelles)
3.Eukarya are more complex and
have a nucleus and membranebound organelles
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Domain Eukarya includes:
•Protista (protozoans,
algae…)
•Fungi (mushrooms, yeasts …)
•Plantae (multicellular plants)
•Animalia (multicellular
animals)
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Skills Practice
1. List the levels of classification from
most broad to most specific.
2. What type of organisms are found in
the kingdom Archaebacteria? Are
these organisms unicellular or
multicellular?
3. What 4 kingdoms are in the Domain
Eukarya?
4. What is the difference between an
autotroph and a heterotroph? Give an
example of each.
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Classification is based on
evolutionary relationships:
• 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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• Phylogenetics- the analysis of the evolutionary
or ancestral relationships among a taxon (group).
• Phylogenetic diagram (tree)- a branching tree
that indicates how closely related species are.
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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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Let’s Create A Cladogram from the following:
Derived Characters
segmented
jaws
hair
placenta
multicellular
limbs
kangaroo
+
+
+
-
+
+
earthworm
+
-
-
-
+
-
amoeba
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-
-
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-
-
lizard
+
+
-
-
+
+
cat
+
+
+
+
+
+
sponge
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-
-
-
+
-
salmon
+
+
-
-
+
-
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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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