Classification
1
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
2
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
3
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”??
4
Confusion in Using Different
Languages for Names
5
Latin Names are Understood by
all Taxonomists
6
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
•
•
7
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
•
8
Carolus Linnaeus
1707 – 1778
• 18th century
taxonomist
• Classified
•
organisms by
their structure
Developed
naming system
still used
today
9
Carolus Linnaeus
•Called the “Father of
Taxonomy”
•Developed the modern
system of naming known
as binomial nomenclature
Two-word name (Genus &
species)
•
10
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
11
Binomial Nomenclature
Which TWO are more closely related?
12
Rules for Naming Organisms
• The International Code for
Binomial Nomenclature contains
•
•
the rules for naming organisms
All names must be approved by
International Naming Congresses
(International Zoological
Congress)
This prevents duplicated names
13
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 (Division – used for plants)
Class
Order
Family
Genus
Species
Most
Specific
15
Dumb
King
Phillip
Came
Over
For
Gooseberry
Soup!
16
Domains
• Broadest, most inclusive taxon
• Three domains
• Archaea and Bacteria are
•
unicellular prokaryotes (no
nucleus or membrane-bound
organelles)
Eukarya are more complex and
have a nucleus and membranebound organelles
17
ARCHAEA
• Kingdom - ARCHAEBACTERIA
• Probably the 1 cells to evolve
• Live in HARSH environments
• Found in:
–Sewage Treatment Plants
(Methanogens)
–Thermal or Volcanic Vents
(Thermophiles)
–Hot Springs or Geysers that are
acid
–Very salty water (Dead Sea;
st
Great Salt Lake) - Halophiles
18
ARCHAEAN
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BACTERIA
• Kingdom - EUBACTERIA
• Some may cause DISEASE
• Found in ALL HABITATS except
harsh ones
• Important decomposers for
environment
• Commercially important in making
cottage cheese, yogurt,
buttermilk, etc.
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Live in the intestines of animals
21
Domain Eukarya is Divided
into Kingdoms
•Protista (protozoans,
algae…)
•Fungi (mushrooms, yeasts …)
•Plantae (multicellular plants)
•Animalia (multicellular
animals)
22
Protista
•Most are unicellular
•Some are
multicellular
•Some are
autotrophic, while
others are
heterotrophic
Aquatic
Ex: Amoebas,
paramecium, Euglena
and Diatoms
•
•
23
• Multicellular,
except yeast
• Absorptive
•
•
Fungi
heterotrophs
(digest food
outside their body
& then absorb it)
Cell walls made of
chitin
Ex: mushrooms,
yeast, black bread
mold.
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Plantae
•Multicellular
•Autotrophic
•Absorb sunlight
to make glucose –
Photosynthesis
Cell walls made of
cellulose
•
25
• Multicellular
• Ingestive
•
•
Animalia
heterotrophs
(consume food &
digest it inside
their bodies)
Feed on plants or
animals
Ex; Reptiles,
Amphibians, Aves,
Mammals, Fish
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Characteristics of Animals
•Fish
There is a great deal of diversity among the animals we call
fish, but they all share certain things in common. All fish:
-live in water
-have fins
-breathe through gills.
•Amphibians
Amphibians include the frogs, toads and salamanders.
Amphibians:
-have smooth or bumpy skin
-are dependent on water for reproduction
-can breathe with lungs or gills depending on the species, but all
-an breathe through their skin.
•Reptiles
Reptiles include lizards, snakes, turtles and crocodilians
(alligators, crocodiles and a couple others). They are
characterized by:
-having tough, dry, scaly skin
-breathing with lungs
-having eggs with a leathery eggshell that does not have to be laid
-in water to survive (though some reptiles do not lay eggs and
instead have
-live births)
-being ectothermic (cold-blooded).
•
Birds
Birds have some fairly obvious common
characteristics:
-feathers
-beaks
-wings
as well as some not so obvious characteristics,
such as:
-remarkably lightweight bones
-being endothermic (warm-blooded).
•Mammals
Mammals are the group of vertebrates that
includes humans, river otters and dolphins.
The characteristics of mammals are they:
-are endothermic (warm-blooded)
-have hair
-breathe air with lungs
-give live births
-produce milk
27
28
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
•
29
30
Basis for Modern Taxonomy
•Homologous structures (same
structure, different
function)
Similar embryo development
Molecular Similarity in DNA,
RNA, or amino acid sequence
of Proteins
•
•
31
Homologous Structures (BONES in the FORELIMBS) shows
Similarities in mammals.
32
Similarities in Vertebrate
Embryos
33
Cladogram
Diagram showing how organisms are related
based on shared, derived characteristics
such as feathers, hair, or scales
34
Primate
Cladogram
35
How are cladograms constructed?
Organisms are grouped together based
on their shared derived characteristics
(trait modified from the ancestral
trait).
Cladogram construction
Given a table of derived characters (traits),
create a cladogram
Step 1 – Create a Venn Diagram
How many organisms are you comparing?
This number will equal the number of circles in your Venn
diagram.
Now count the number of characters each organism has.
This will be the order that you place the organisms in the Venn
Diagram.
Venn Diagram
Placenta:Human
Mammary glands: Kangaroo & Human
Two pairs of limbs: Bullfrog, kangaroo & Human
Vertebrae: Shark, bullfrog, kangaroo & humans
Step Two – Convert the Venn Diagram
into a Cladogram
Kangaroo
Bullfrog
Shark
Human
Placenta
Mammary Glands
Two pairs
of limbs
Vertebrae
Convert the Venn Diagram
into a Cladogram
Lizard
Trout
Human
Earthworm
Hair
Legs
Vertebrae
Independent Practice Problems:
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
44
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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Chapter 18 Classification