Evidence for Evolution
BioH Ch 18
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Petrified tree sap = “amber”
(Basis for Jurassic Park movies)
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Fossil Evidence
In 2004, scientists digging in the Canadian Arctic
unearthed fossils of a half-fish, half-amphibian
that all but confirmed paleontologists' theories
about how land-dwelling tetrapods–four-limbed
animals, including us–evolved from fish.
It is a classic example of a transitional form, one
that bridges a so-called evolutionary gap between
different types of animal.
Let’s examine five important cases.
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Fossilization
“Lucy”
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Stratification
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Evidence of evolution can lead to the formation of a
timeline of development of life on Earth…
Fossil records
Relative Dating
Radioactive dating
Geologic Time Table
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ERA’s correspond
with major
extinction events
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Common ancestors?
Comparative Morphology
Morphological
divergence
Homology
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Morphological divergence
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Morphological Convergence
Fish
Mammal
Bird
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“Ontogeny recapitulates phylogeny”
Embryological Evidence
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Comparative Biochemistry Evidence
DNA, RNA, proteins comparisons between species
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Systems of Classification
Based on SIMILARITIES
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Visual
Location
Anatomical
Physiological
Genetic
???
Easiest to identify?
MOST important/
BEST relationships?
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Linnaeus’s System
• Hierarchy
• Seven levels - Taxons
– Kingdom
– Phylum
– Class
– Order
– Family
– Genus
– Species
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King Philip?
King
Philip
Came
Over
For
Good
Soup
Kingdom
Phylum
Class
Order
Family
Genus
Species
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Binomial Nomenclature
Genus and Species name
Polar bear – Ursus maritimus
Grizzly Bear – Ursus arctos
Giant Panda – Ailuropoda
melanoleuca
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Old vs. Modern Systems
Evolutionary classification (descent characteristics):
 Segmented bodies
Derived characteristics =
 Jointed limbs
CLADOGRAM
 Exoskeleton that is shed
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Exercise
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Taxonomy
Identifying, classifying species
Classification schemes
Binomial system
Phylogeny
K-P-C-O-F-G-S
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Kingdoms
Archaebacteria – Ancient bacteria, unicellular, prokaryote.
Found in extremely harsh environments.
Eubacteria - More modern bacteria, uniclelluar, prokaryote.
“Common bacteria”
Protista – Eukaryote, unicelluar or multicellular. Autotroph or
heterotroph. Pathogens and parasites.
Fungi – Multicellular, eukaryote. Heterotroph. Decomposers,
pathogens, parasites.
Plantae - Multicellular, eukaryote. Autotrophs
Animalia - Multicellular, eukaryote. Heterotroph.
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Radiometric
Dating
Radioactive decay
in everyday life
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A Changing Earth
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Evidence of Change
Life
Fossil evidence
Stratification
Radiometric dating
Geology
Sedimentary layers
Similar mineralization
Aging of mountain ranges
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What’s in the future?
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