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Transcript of Evolution & Classification - Linn–Benton Community...
4/3/2014
1
Evolution & Classification
BI 101 General Biology
Learning Goals
1. Define evolution and understand
evolution by Natural Selection.
2. Understand how biologist classify
organisms.
3. Recognize Linnaean Taxonomic
hierarchy of classification.
4. Interpret phylogenetic trees (aka a
phylogeny or evolutionary tree)
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1. What is evolution?
2. Can religion and evolution
be compatible?
Discuss what you think evolution is with
your groups
~ 5 min
Evidence for evolution
Genetics: DNA
Paleontology: Fossils
Morphology: Homology
Biogeography :Geographic distribution
of organisms
Microevolution- observed changes
within populations of a species
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Evidence for evolution
Genetic
Genes coding proteins in our DNA is
Yeast - 45% identical
Fruit flies - 60% identical
Chickens - 90% identical
Rabbits - 95% identical
Chimpanzees - 98% identical!
Evidence for evolution:
Morphology Homology - A characteristic shared by
different organisms with common
ancestry
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Evidence for evolution
Morphology Vestigial organs– have no use
Example: appendix, wisdom teeth, human
tailbone, hind leg bones in whales,
Ostrich wings (they don’t fly)
Texas blind
salamander:
eyes that do
not see
Evidence for evolution
Biogeography Geographic distribution of organisms
Example: the finches of the Galapagos
Islands
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How can we organize
the diversity of life?
Taxon: A Ranked Hierarchy
Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Order: Rosales
Family: Rosaceae
Genus: Malus
Species: Malus pumila L.
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Organizing Principle:
We can use relationships between
organisms to organize the diversity
of life
Descent with modification
Making Sense of it All
Traditional classification schemes
rank species into a hierarchy
Newer methods group species by
shared ancestry.
This reflects evolutionary history.
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Kingdoms and Domains
Bacteria Archaea Eukarya
Bacteria Archaea Protista Plantae Fungi Animalia
Monera Protista Plantae Fungi Animalia
The three-domain system
The six-kingdom system
The traditional five-kingdom system
Phylogeny Phylon = tribe (Greek)
Genesis = origin (Greek)
The evolutionary history of a species or group of species.
Goal is to show relationships and patterns of descent i.e. to make models called:
Phylogenetic Trees
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Hypothetical genealogy
of local population of
plants
Fig. 2. How genealogy of sexual
population is included in a phylogenetic
tree
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Tree diagram is meant to represent an
actual history of evolutionary lineages that
have branched over time
Reading the tree is like
traveling through family history
Speciation events occur at the
branch points, show when
ancestral lineage gives rise to
daughter lineage.
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Each living species has a unique lineage
as well as parts shared with others
Some important terms used
to describe phylogenetic trees
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A clade includes all
and only the
descendants of a
particular ancestor
A clade includes all and only
the descendants of a particular
ancestor
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Four trees, all depict
same evolutionary history
• Now convince your partner– What do you
think?
• Why do you think your answer is right?
• Did you change your mind?
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• Now convince your partner– What do you
think?
• Why do you think your answer is right?
• Did you change your mind?
• Now convince your partner– What do you
think?
• Why do you think your answer is right?
• Did you change your mind?
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• Now convince your partner– What do you
think?
• Why do you think your answer is right?
• Did you change your mind?
What is misleading about this
picture?
It implies we evolved from apes we see
today!
It also implies individuals evolve, while
we know populations evolve
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Discuss Which organism would you venture to
guess is more closely related to the
Chinook salmon: a Great white shark or a
Beaver? Why?
Discuss
Ch 24 in textbook
See page 448, figure 24-1
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Ch 18 p. 348-349
Work on the exercise at the end of the
section
Then compare answers with your group
members
Additional Resources:
http://tolweb.org/tree/phylogeny.html