EVOLUTION IS

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EVOLUTION IS

• GENETIC CHANGE IN A POPULATION OVER TIME

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Types of evidence of evolution

• Fossils
• Homologies
• Anatomical
• Molecular
• Developmental
• Biogeography
• Observable Events

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Fossil Record

• Helps scientists understand pathway of evolution
• Paleontology
• Fossil
• Remains ex. bone, tooth, or shell
• Traces ex. burrow, footprint, or imprint

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Fossil Record

• Most fossils are found in layered sedimentary
  rock
• Oldest fossils are in the lowest layer
• Newest fossils are in the top layer

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Fossil Record

• Comparing fossils from different layers shows
• Life on Earth has changes
• Increased number of life forms

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Fossil evidence
Reduction of toes over time
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Anatomical Homologies

• Homologous Structures Similar structure but
  different function
• Shows
• Similar genes
• Common ancestor

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Anatomical Homologies

• Vestigial Structure Body part reduced in
  function in a living organism but may have been
  used in an ancestor
• Shows Organisms evolutionary past

Whale pelvis tailbone humans
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Developmental Homologies

• Shows
• Similar genes
• Common ancestor

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Developmental Homologies
Fish, reptiles, birds, mammals (yes, even us!)
all have a tail, limb buds pharyngeal pouches
in the early stages of development
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Molecular Homologies

• DNA the genetic code
• DNA codes for amino acids proteins
• Universal Genetic code
• The similarity in DNA shows
• A probable common ancestor for all life on Earth

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Molecular Homologies

• The amino acid sequence in a particular protein
  is compared between organisms.

Number of differences from human hemoglobin
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Molecular Homologies

• Comparing amino acid sequence shows

Amino Acid Difference in Hemoglobin Compared with
Human

• Closeness of relationship
• A probable common ancestor

Amino Acid Sequencing is probably the STRONGEST
evidence for relationships among organisms.
Species Difference
Gorilla 1
Rhesus Monkey 8
Mouse 27
Chicken 45
Frog 67
Lamprey 125
Human hemoglobin has 146 amino acids
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Molecular Homologies
Amino Acid Difference in Hemoglobin Compared with
Human
Species Difference
Gorilla 1
Monkey 8
Mouse 27
Chicken 45
Frog 67
Lamprey 125

• CLADOGRAM diagram that shows the evolutionary
  relationship among a group of organisms.

B
A
C
D
What organism belongs at each branch?
Where would the common ancestor be?
E
F
G
Common ancestor
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Biogeography

• Geographic distribution

• organisms living far apart may be similar because
  they share a common ancestor

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Observable Events

• Some changes in species have been observed and
  studied
• Shows Evolution is an ongoing process

Peter Rosemary Grants Study of Beak Size Shift in Darwins Finches H. Kettlewells Study of Peppered Moth Color Shifts

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Tempo of Evolution