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EVIDENCE THAT SUPPORTS EVOLUTION. Pillar #1: The Fossil Record. What is a fossil?. The remains or evidence of an organism Fossilized bone, wood, shell, or dung Casts, imprints, or molds Amber or tar entrapments Imprints of footprints or borings. Fossil Facts.

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what is a fossil
What is a fossil?
  • The remains or evidence of an organism
    • Fossilized bone, wood, shell, or dung
    • Casts, imprints, or molds
    • Amber or tar entrapments
    • Imprints of footprints or borings
fossil facts
Fossil Facts
  • Most are found in sedimentary rock.
  • The fossil record shows that life has changed over time.
    • The fossil record is very incomplete.
    • Fossils give us a glimpse into the morphology of organisms now extinct.
interpreting fossil evidence
Interpreting Fossil Evidence
  • Relative Dating – the age of a fossil is estimated by comparing it to other fossils in rock layers
    • Rock layers form in order of age – the oldest layers are on the bottom
interpreting fossil evidence1
Interpreting Fossil Evidence
  • Radioactive Dating – using radioactive decay to assign absolute ages to fossils
    • A half-life is the length of time required for ½ of the radioactive atoms in a sample to decay

If 100 g of Carbon-14 decays until only 25 g of carbon is left after 11, 460 years, what is the half-life of carbon-14?

homologous structures
Homologous Structures
  • Structures that have similar characteristics but may or may not have similar functions.
    • Ex: forearms of vertebrates
vestigial structures
Vestigial Structures
  • Structures that are diminished in size and/or function.
    • Ex: eyes of moles

Homologous & Vestigial structures give evidence of DIVERGENT EVOLUTION.

    • They suggest that descendents DIVERGED (became different) as the distance from the common ancestor increased.
analogous structures
Analogous Structures
  • Structures with the same function in organisms that are not closely related.
    • Ex: the wings of birds and the wings of insects.
    • Ex: thorns of the rosebush and the quills of the porcupine.

Analogous structures suggest CONVERGENT EVOLUTION.

    • Organisms did not descend from a common ancestor, they independently evolved similar adaptations to survive in similar environments.
what is biogeography the study of
What is biogeography?The study of. . .
  • Where species live on earth and why
  • How organisms are adapted to their environment
scientists study the
Scientists study the
  • Morphology of Embryo
  • The fate of particular embryonic tissue
a ll organism have
All organism have…
  • The same “Genetic Code”
    • 4 DNA nucleotides
    • Same 64 mRNA codons that code for the same amino acids
  • Ribosomes as the site of protein synthesis
  • ATP as the energy currency
  • Plasma membranes that consist of a phospholipid bilayer w/ imbedded proteins
Compare common proteins
    • Count and compare how many of the amino acids differ
  • Compare the nucleotide sequences of DNA
    • the closer the DNA sequences, the more closely related the organisms are.
examples of observed natural selection
Examples of OBSERVED Natural Selection
  • DDT Resistant Mosquitoes
  • Antibiotic Resistant Drugs
  • Darwin’s Finches