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Unit 11: Classification
INSTRUCTIONS FOR NOTETAKING: Copy all words
unless otherwise indicated.
• Copy no tables or diagrams unless otherwise
indicated.
• Use Cornell (2-column style) format.
• Leave room after each EQ for a 3 sentence summary.
video use later
• Essential Question #1:
How and why are organisms classified the way
they are? (Include HIERARCHY and
EVOLUTIONARY RELATIONSHIPS.)
How Are Organisms Classified?
Organisms can be classified in one of two ways:
1. Based on P________ similarities
2. Based on E_________ relationships.
This is a
pangolin,
native to
Africa &
Asia.
They are
mammals!
Classification Method #1: Based on physical similarities
• Taxonomy is the science of naming and classifying
organisms.
• Linnaeus developed the S______ naming system based on
physical similarities, still used today.
White oak:
Quercus alba
Classification Method #1: Based on physical similarities
• Binomial nomenclature is a T___-part scientific naming
system Linnaeus developed
– uses Latin words
– always written in italics
– two parts are the genus name and species descriptor
(always capitalized) (never capitalized)
Example: Homo sapiens
Classification Method #1: Based on physical similarities
• Genus name- S____ in the same genus are thought to be
closely related.
• Scientific names help scientists to communicate.
– Some species have very similar common names.
– Some species have many common names.
Classification Method #1: Based on physical similarities
Linnaeus’ classification system has S_____ levels.
• Each level is
included in the
level above it.
• Levels get
increasingly
specific from
kingdom to
species.
• (Copy the
categories -blue
tabs)
Classification Method #1: Based on physical similarities
The Linnaean classification system has limitations.
• Linnaeus taxonomy doesn’t account for M_____ (DNA)
evidence.
– The technology didn’t exist during Linneaus’ time.
– based only on physical similarities.
Is there a more ACCURATE way of determining
relationships between organisms?
• Physical similarities are
not always the result of
C____ relationships.
• G_____ similarities more
accurately show
evolutionary relationships.
Classification Method #2:Based on Evolutionary
Relationships
M_____ classification is based on evolutionary
relationships. (which relies on DNA evidence!)
Classification Method #2:Based on Evolutionary
Relationships
• We make evolutionary trees to show relationships
– evidence from living species, F____ record, and
molecular data
– shown with branching tree diagrams or “CLADOGRAMS”
Classification Method #2:Based on Evolutionary
Relationships
– A clade is a group of species that shares a C____
ancestor.
– Each species
in a clade
shares some
traits with the
ancestor.
– Each species
in a clade has
traits that have
changed.
Classification Method #2:Based on Evolutionary
Relationships
• Derived characteristics are T____ shared in different
degrees by clade members.
1 Tetrapoda clade
– more closely
related species
share more
derived characters
2 Amniota clade
3 Reptilia clade
4 Diapsida clade
5 Archosauria clade
FEATHERS &
TOOTHLESS
BEAKS.
– represented on
cladogram as hash
marks
SKULL OPENINGS IN
FRONT OF THE EYE &
IN THE JAW
OPENING IN THE SIDE OF
THE SKULL
SKULL OPENINGS BEHIND THE EYE
EMBRYO PROTECTED BY AMNIOTIC FLUID
FOUR LIMBS WITH DIGITS
DERIVED CHARACTER
Classification Method #2:Based on Evolutionary
Relationships
CLADE
• Nodes represent
the most recent
common A____ of
a clade.
1 Tetrapoda clade
2 Amniota clade
3 Reptilia clade
4 Diapsida clade
5 Archosauria clade
FEATHERS AND
TOOTHLESS
BEAKS.
SKULL OPENINGS IN
FRONT OF THE EYE AND
IN THE JAW
• Clades can be
identified by
snipping a branch
under a node.
OPENING IN THE SIDE OF
THE SKULL
SKULL OPENINGS BEHIND THE EYE
EMBRYO PROTECTED BY AMNIOTIC FLUID
NODE
FOUR LIMBS WITH DIGITS
DERIVED CHARACTER
• Essential Question #2:
Why has the way we
classify organisms changed
over time?
Classification Method #2: Based on Evolutionary
Relationships
Molecular evidence reveals species’ relatedness.
• Molecular data may confirm classification based on
physical similarities.
• Molecular data may lead scientists to propose a N___
classification.
• DNA is usually given the last word by scientists.
Classification Method #2: Based on Evolutionary
Relationships
Molecular clocks provide clues to evolutionary history.
Molecular clocks use M___ to estimate evolutionary time.
• Mutations add up at a constant rate in related species.
– This rate is the ticking of the molecular clock.
– As more time passes, there will be more mutations.
Mutations add up at a fairly
constant rate in the DNA of
species that evolved from a
common ancestor.
DNA sequence from a
hypothetical ancestor
Ten million years later—
one mutation in each lineage
Another ten million years later—
one more mutation in each lineage
The DNA sequences from two
descendant species show mutations
that have accumulated (black).
The mutation rate of this
sequence equals one mutation
per ten million years.
Classification Method #2: Based on Evolutionary
Relationships
• Scientists estimate mutation rates by linking molecular data
and the F___ appearance of a species in fossil record.
Notice how scientists compare various
data sources (amino acids, fossils) to
better understand relationships. It is
helpful to have more than 1 source of
information!
• Essential Question #3:
What are the distinguishing
characteristics of the DOMAINS
and KINGDOMS of living
organisms?
Recognize distinguishing characteristics of organisms
(prokaryotic vs eukaryotic, unicellular vs multicellular,
autotrophs vs heterotrophs, environments)
Classification Groups
• Domain, Kingdom, Phylum, Class,
Order, Family, Genus, species
•
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Classification Groups
•There is a hierarchy of groups (taxa) from broadest to
most specific
• Domain
BROADEST TAXON
•
Kingdom
•
Phylum (Division – used for plants)
•
Class
•
Order
•
Family
•
Genus
Most Specific
•
Species
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• Dumb
• King
• Phillip
• Came
• Over
• For
• Gooseberry
• Soup!
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READ, BUT DON’T COPY
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The “Tree of Life”: Domains & Kingdoms
The current tree of life has three domains.
The three domains in the tree of life are B_____, Archaea,
and Eukarya.
– domain model more clearly shows P_____ diversity
The “Tree of Life”: Domains & Kingdoms
Kingdoms are smaller groups “under” domains
Classification is always a work in progress.
• The tree of life shows our most current understanding.
• New discoveries can lead to changes in classification.
– Until 1866: only two kingdoms: A____ and P_____
The “Tree of Life”: Domains & Kingdoms
Classification is always a work in progress.
– 1866: all single-celled
organisms moved to
kingdom Protista
Plantae
Animalia
Protista
– 1938: prokaryotes moved
to kingdom Monera
Archea
– 1959: F_____ moved to
own kingdom
Fungi
Bacteria
– 1977: kingdom Monera
split into kingdoms Bacteria and
Archaea
The “Tree of Life”: Domains & Kingdoms
READ, BUT DON’T COPY
Kingdoms Archaea and Bacteria
Archaea
Bacteria
Organization
Unicellular
Unicellular
Where Found
Harsh Environments
(sewers, hot springs,
geysers)
All habitats, except harsh
ex: stomach of animals
Functions
Develop medicines
Decomposers in
environment, used
commercially (cheese,
medicine)
Cell Wall
Not peptidoglycan
Peptidoglycan
Obtain Food
Absorption,
Photosynthesis
chemosynthesis
Absorption,
Photosynthesis
chemosynthesis
Motility
Some are able to move
Some are able to move
Live in the intestines of animals
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READ, BUT DON’T COPY
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Binomial Nomenclature
Which TWO are more closely related?
copyright cmassengale
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