For this ppt, have the moth simulation ready

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• For this ppt, have the moth simulation ready
• Have blind spot test ready

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Chapter 22Evidence for Evolution

• How has evolution risen in status to the level of
  THEORY, the same level as gravity or plate
  tectonics?
• Through repeated observations from many areas of
  life sciences.

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Evolution Objectives

• If given the statement, There is little evidence
  for evolution, be able to respond using
  measurable evidence.
• Fossil evidence
• Anatomical Evidence
• Molecular Evidence
• Describe the contributions of Charles Darwin and
  explain how Hutton and Lyell informed Darwins
  understand of Evolution

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Evidence of Evolution

• What is probably the first evidence that living
  things have changed over time?
• What additional clues have been added since then?

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Beaks as Evidence pg 457

• Darwin saw finches on the Galapogos Islands (and
  tortoises and armadillo fossils in South
  America, and lots more).
• What did he notice about these finches?
• from an original paucity of birds in this
  archipelago, one species has beenmodified for
  different ends. Can someone rephrase this?
• Are you able to see things in a different way
  than they have traditionally been seen?

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Grants Modern Observations Support Darwins
Hypthesis

• The Grants did measurable experiments to measure
  characteristics such as beak size.
• Details on following slide

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Figure 23.2
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Average beak depth (mm)
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0
1976 (similar to the prior 3 years)
1978 (after drought)
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Figure 22.2
1809
Lamarck publishes his hypothesis of evolution.
1798
Malthus publishes Essay on the Principle of
Population.
1812
1858
Cuvier publishes his extensive studies of
vertebrate fossils.
1795
While studying species in the Malay Archipelago,
Wallace (shown in 1848)sends Darwin his
hypothesisof natural selection.
Hutton proposes his principle of gradualism.
1830
Lyell publishes Principles of Geology.
1790
1870
1809
1831?36
1859
Charles Darwin is born.
Darwin travels around the world on HMS Beagle.
On the Origin of Species is published.
1844
Darwin writes his essay on descent with
modification.
The Galápagos Islands
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Geology informs Darwin

• Geologists James Hutton and Charles Lyell
  perceived that changes in Earths surface can
  result from slow continuous actions still
  operating today
• Lyells principle of uniformitarianism states
  that the mechanisms of change are constant over
  time
• This view strongly influenced Darwins thinking

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Industrial Melanism

• Industrial Revolution and the Peppered Moth
• How does this relate to the Clean Air Act?
• See peppered moth simulation
• What types of selection can you attribute this to?

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Figure 53.22
7 6 5 4 3 2 1 0
Human population (billions)
The Plague
8000 BCE
4000 BCE
2000 CE
1000 BCE
2000 BCE
3000 BCE
1000 CE
0
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Industrial Melanism

• Industrial Revolution and the Peppered Moth
• How does this relate to the Clean Air Act?
• See peppered moth simulation
• What types of selection can you attribute this to?

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Selection Ponderables

• Does selection act directly on genotypes or
  phenotypes?
• Which is more likely to be selected against,
  deleterious mutations that are dominant or those
  that are recessive? Why?
• Can selection create perfect organisms?
• (Humans backs are evolved from 4-legged
  ancestors and not fully compatible w upright
  posture, so many older people have backpain)

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• Blind Spot Test- (See Class Set Handout)

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Fossil Evidence

• How can the age of fossils be determined?
• Relative Dating
• Absolute Dating

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Figure 22.3
Sedimentary rock layers (strata)
Younger stratum with more recent fossils
Older stratum with older fossils
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Fossil Evidence

• We found orange juice with 1/8 of its original
  32P in the lab cabinets during cleanup. 32P has a
  half-life of about 14 days. How long had the
  orange juice been there?
• That is 3 half-lives, so about 3 x 14 42 days.
  Drink Up!

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Anatomical Evidence

• Homologous structures
• Structures that have different functions but
  arrived from same body part.
• Human arm, bat wing, porpoise flipper

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Figure 22.15
Homolgous Structures
Humerus
Radius
Ulna
Carpals
Metacarpals
Phalanges
Whale
Bat
Human
Cat
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Figure 22.20
Phylogenetic Tree
Other even-toedungulates
Hippopotamuses
Pakicetus
Rodhocetus
Commonancestorof cetaceans
Dorudon
Livingcetaceans
70
60
50
40
30
20
10
0
Pelvis
Tibia
Key
Millions of years ago
Femur
Foot
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Did you know there are pelvic bones in snakes? In
whales? Why? They are vestigial structures What
vestigial structures do humans have? Appendix
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Ankle bone of cetaceans page 465

• What are cetaceans?
• Mammal group including whales, dolphins, and
  porpoises.
• Fossils of Pakicetus show that it had an ankle
  bone with characteristics like that of an even
  toed ungulate (deer or pig).

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Figure 22.19
Most mammals
Cetaceans and even-toed ungulates
(a) Canis (dog)
(b) Pakicetus
(c) Sus (pig)
(d) Odocoileus (deer)
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Embryological Evidence

• Findings from Development
• Ontogeny recapitulates phylogeny.
• Developing embryo tells a story
• gill pouches, tail, fur (lanugo)

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Figure 22.16
Embryological Evidence
Pharyngealpouches
Post-analtail
Chick embryo (LM)
Human embryo
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Which Embryo is Which? Click Link
http//www.exploratorium.edu/exhibits/embryo/embry
oflash.html
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Darwinian Prediction

• Darwin found an orchid whose reproductive organs
  were 30 cm deep inside the flower.
• Darwin postulated that a pollinator would be
  found with a 30 cm proboscis.
• It took 40 years, guess what scientists found!...

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Darwinian Prediction

• Xanthopan morganii praedicta
• The Hawk Moth
• Guess the length of the proboscis?
• Notice its last name?
• What kind of logic?
• Inductive or deductive?

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• What our new understanding of genetics tell us
  about our model of evolution?

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Molecular Record

• The more amino acid (or DNA base pair)
  differences, the greater the evolutionary
  distance.
• The trunk of the tree represents similar traits
  or molecules (depending on how tree was made).
  Each branch represents a divergence.

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Convergent Evolution

• Two separate groups (branches on evolutionary
  tree) display similar characteristics.
• Analogous Structures
• Ex Placental mammals often have a marsupial
  cousin wolf / tasmanian wolf.

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Evolution of Drug-Resistant Bacteria

• The bacterium Staphylococcus aureus is commonly
  found on people
• One strain, methicillin-resistant S. aureus
  (MRSA) is a dangerous pathogen
• S. aureus became resistant to penicillin in 1945,
  two years after it was first widely used
• S. aureus became resistant to methicillin in
  1961, two years after it was first widely used
• We will discuss in class next quarter.

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Island Evolution

• An ideal location to study evolution. Organisms
  can be seen that are similar to the mainland
  species that they are nearest, but with traits
  adapted to a specific island.

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Illustrative Examples

• Number of heart chambers in animals
• Opposable thumbs
• Many apes, oppossums, koalas, pandas. Some
  birds have opposable digits, as did some
  dinosaurs.
• Absence of legs in some sea mammals
• Whales have a pelvic bone, even though they have
  no legs.

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Species that lack diversity are at risk for
extinction

• Can you think of examples?
• Corn- Corn Rust Disease
• Potatoes- Irish Potato Famine changed history
• California condors- prone to epidemic disease
• Prairie chickens- once numbering in the millions-
  now only about 60 left in the wild
• Tasmanian Devil- We will read up on this

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Evolution Objectives

• If given the statement, There is little evidence
  for evolution, be able to respond using
  measurable evidence.
• Fossil evidence
• Anatomical Evidence
• Molecular Evidence
• Describe the contributions of Charles Darwin and
  explain how Hutton and Lyell informed Darwins
  understand of Evolution

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