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
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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
Which TWO are more closely related?
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Rules for Naming Organisms
• The International Code for
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Binomial Nomenclature contains
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
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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 (Division – used for plants)
Class
Order
Family
Genus
Species
Most
Specific
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Dumb
King
Phillip
Came
Over
For
Gooseberry
Soup!
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Domains
• Broadest, most inclusive taxon
• Two domains
• Prokarya are unicellular
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prokaryotes (no nucleus or
membrane-bound organelles)
Eukarya are more complex and
have a nucleus and membranebound organelles
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The Domain Prokarya is divided into two
Kingdoms:
•Eubacteria(true bacteria)
•Archaebacteria(ancient bacteria)
Domain Eukarya is Divided
into Kingdoms
•Protista (protozoans,
algae…)
•Fungi (mushrooms, yeasts …)
•Plantae (multicellular plants)
•Animalia (multicellular
animals)
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Protista
•Most are unicellular
•Some are multicellular
•Some are autotrophic, while
others are heterotrophic
•Aquatic
•Protists include all
microscopic organisms that are
not bacteria, not animals, not
plants and not fungi.
Ex. Paramecium, amoeba,
alga,euglena
•
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• Multicellular, except yeast
• Absorptive heterotrophs
Fungi
(digest food outside their
body & then absorb it)
Cell walls made of chitin
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•Fungi are organisms that
biologists once confused
with plants, however,
unlike plants, fungi
cannot make their own
food. Most obtain their
food from parts of plants
that are decaying in the
soil.
• Ex. Mushrooms, molds,
yeast
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Plantae
•Multicellular
•Autotrophic
•Absorb sunlight to make
glucose – Photosynthesis
•Cell walls made of
cellulose
•With over 250,000
species, the plant
kingdom is the second
largest kingdom.
Ex. Trees, shrubs,
flowers, mosses, ferns
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• Multicellular
• Ingestive
heterotrophs
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Animalia
(consume food &
digest it inside
their bodies)
Feed on plants
or animals
The animal
kingdom is the
largest kingdom
with over 1
million known
species.
• ex.
lions, tigers
and bears
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Eubacteria:
Like archaebacteria, eubacteria are
complex and single celled. Most
bacteria are in the EUBACTERIA
kingdom.
Eubacteria: cont
They are the kinds found everywhere and
are the ones people are most familiar
with. Eubacteria are classified in their
own kingdom because their chemical
makeup is different. Most eubacteria are
helpful. Some produce vitamins and
foods like yogurt. However, these
eubacteria, Streptococci pictured above,
can give you strep throat!
Archaebacteria:
Archaebacteria
In 1983, scientists tool samples from a
spot deep in the Pacific Ocean where
hot gases and molten rock boiled into
the ocean form the Earth’s interior.
To their surprise they discovered
unicellular (one cell) organisms in the
samples. These organisms are today
classified in the kingdom,
Archaebacteria.
Archaebacteria are found in
extreme environments such as
hot boiling water and thermal
vents under conditions with
no oxygen or highly acid
environments.
Finding Archaebacteria: The hot springs
of Yellowstone National Park, USA,
were among the first places
Archaebacteria were discovered. The
biologists pictured above are
immersing microscope slides in the
boiling pool onto which some
archaebacteria might be captured for
study.
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Taxons
•Most genera contain a
number of similar species
•The genus Homo is an
exception (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
Molecular Similarity in DNA,
RNA, or amino acid sequence
of Proteins
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Homologous Structures (BONES in the FORELIMBS) shows
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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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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