Ultra Deep Field

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Ultra Deep Field

• Here is what happened when professional
  astronomers pointed the Hubble Space Telescope at
  absolutely nothing and left it there, first for
  10 days, and then for 11 days. Then they made the
  images into a 3-D presentation. Hang on to your
  seat! By the way, 13 billion light years are
  about equal to 880,000,000,000,000,000,000,000
  (880 sextillion) miles. Be sure you have your
  sound on. ... and this was aimed at a blank spot
  in the sky?
• Hubble Ultra Deep Field 3D

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Evolution, Change and Diversity

• Adaptation and Change

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What does it mean to be alive?

• Characteristics of a living organism
• Made of i) carbon, hydrogen, nitrogen, and
  oxygen
• ii) cells (organization of life processes)
• Able to iii) reproduce
• iv) grow and develop
• v) move
• vi) consume food, remove waste
• vii) maintain homeostasis

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Importance of Adaptation

• Variety is the spice of life True or False?
• What is the value of diversity?
• All plants and animals, regardless of size,
  shape, or level of complexity, share certain
  characteristics.
• Requirements for energy
• Basic cell structure and function
• Adaptation to a particular habitat

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Adaptations

• Inheritable changes in an organisms
• appearance
• behaviour
• structure
• mode of life
• that make the organism better able to survive in
  a particular environment

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The Theory of Evolution

• Attempts to explain why living organisms are so
• different in form and function
• while being
• similar in biochemistry molecular makeup
• A process by which populations of living things
  change over a series of generations
• Does not include individual change or development

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Evolution Reversed?
The Great Human Odyssey CBC Documentary Series
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Evidence for Evolution

• Direct Evidence
• Fossil Record
• Fossil formation Geological Time Scale
• Carbon Dating Biogeography
• Rapid Reproduction
• Bacteria produce many generations in a short
  period
• Indirect Evidence
• Living Organisms
• Embryology
• Anatomy
• Physiology
• Biochemistry

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The Fossil Record

• A fossil is any trace of an organism that lived
  long ago
• Examples
• Enclosed in resin (amber)
• Covered by sediment that eventually becomes rock
• Minerals filter into the body and turn to rock
  cast/copy (petrification)
• Trace fossils tracks or impressions left in
  soft sediment that later hardens

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Observe How Fossils Are Made
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Law of Superposition

• Most sedimentary rocks are laid down in
  horizontal layersincreasing in age from top to
  bottom as long as the layers are not disturbed.
• Fossils found in the undisturbed lower layers of
  sedimentary rocks are usually older and less
  complex than those found in upper layers.
• Scientist can use this rule to determine the
  relative age of many fossilized organisms.

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The Fossil Record contd

• Geologists estimate age of sedimentary rock based
  on its thickness and location above or below
  other layers
• Relative age and radioactive dating used
  collectively helps determine both
• the age of the Earth (4.5 billion years old)
• when the 1st life forms appeared (3.5 billion
  years ago)
• By piecing together fossil evidence according to
  age and similarity of structure, scientists have
  been able to study patterns of relationships
  among organisms
• phylogeny ? evolutionary history

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Radiometric Dating (Geologic Time Scale)

• What is radiometric dating?

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Radioactive Dating

• Scientists calculate the ages of rocks and
  fossils accurately by measuring the decay of
  radioactive isotopes
• Ex) potassium-40 uranium-238 carbon-14
• Carbon-14 Method used to date rocks and fossils
  younger than 50 000 yrs
• Carbon has 2 isotopes
• C14 turns into N14
• C14 has a half-life of 5730 yrs
• Scientists know the approximate percentages the
  organisms start with compare this to the present
  state

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How Do We Know Evolution Happens?Discussion
Questions

• Gingerich discusses specifically only the whale
  fossils found in Egypt's "valley of the whales,"
  but he points out that this now desert area was
  once a sea. Discuss the other kinds of fossils,
  and the types of rocks that must have been
  present for him to make this conclusion.
• Examine the cladogram of whales and their
  ancestors presented in this video. Note that this
  diagram does NOT show modern whales evolving from
  any specific fossil form, but form the common
  ancestors of known fossil species and modern
  animals. Discuss the important difference between
  this view of evolutionary history, and the old
  view -- which often attempted to identify
  specific fossils as THE ancestors of a living
  form.
• Discuss the similarities and differences between
  whale flippers and flukes and fish fins, using
  the scientific terms "homologous structures" and
  "analogous structures" in the discussion.

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What about mummies?

• Leonardo the mummified dinosaur

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Secrets of the Dinosaur Mummy

• http//watch.discoverychannel.ca/clip93695
• http//watch.discoverychannel.ca/clip93694

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Biogeography

• Discrepent Event
• Animals that evolved from similar ancestors on
  different continents
• These ancestors had no way to get between
  continents at the time
• Too much of a coincidence?
• Plate tectonics and Pangaea

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Biogeography
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Biogeography
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Common Ancestors
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Conclusions

• Life forms have become more complex over time
  while many simple life forms continue to exist
• Many fossils show strong similarities to existing
  organisms
• Disadvantage fossil records are rare and
  incomplete

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Evidence from Living Organisms

• Embryology
• Anatomy
• Physiology
• Biochemistry

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Embryology

• The early stages of development show a number of
  relationships not obvious in the fully grown
  organisms.
• The more alike the development of 2 organisms,
  the more closely related they are.
• They probably inherited the same basic body plan
  from a common ancestor
• As development progresses their patterns become
  more different

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Comparative Anatomy (CBC Info Morning Science
Corner, May 30, 2012)Homologous Structures

• Same basic structure and same pattern of early
  growth but may serve different functions
• Overall pattern of structure still resembles
  common ancestor
• Inherited structures become modified due to
  gradual adaptation to different environments
• The greater number of homologous structures two
  organisms share, the more closely related they are

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Homologous bones from human (I), dog (II), pig
(III), cow (IV), tapir (V) and horse (VI)

• r Radius, u Ulna, a Scaphoid, b Lunare,
  c Triquetrum, d Trapezium, e
  Trapezoid, f Capitatum, g Hamatum, p
  Pisiforme

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Becoming Human Activity
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Divergent Evolution

• The presence of similar structures (e.g. bone
  structure) in very different animals leads
  scientists to believe that these animals had a
  common ancestor
• Divergent evolution is when two or more species
  evolve from one common ancestral species

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Analogous Structures

• Similar functions and, perhaps, appearances, but
  are quite different anatomically
• Indicates these organisms did not evolve from a
  common ancestor

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Convergent Evolution

• Animals that occupy a similar niche, regardless
  of ancestry, often evolve parts that function
  similarly
• The underlying structures may not be the same,
  but they serve the same purpose
• These are called analogous structures

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Vestigial Organs

• Structures that have no function in the living
  organism, but may have been used in the ancestors
• May be homologous with still-used structures in
  other related organisms
• As the organism adapts to a new lifestyle, it
  changes in form and behaviour, the once useful
  structure reduces size and function

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Biochemistry

• Chemical analysis show that similar organisms
  have similar chemical structures
• DNA molecules
• Amino acid sequences
• Certain proteins
• Ex) Cytochrome C
• Some scientists consider this the most compelling
  evidence for evolution

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Physiology

• Similarities among the functions of any of the
  parts of the organisms
• Example digestion, waste excretion, hormone
  function, muscle movement

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Selective Breeding

• Within a population (breeding group) of organisms
  there is constant change over time
• Mutation and duplication of existing alleles can
  produce new alleles or genes
• Meiosis and fertilization can reshuffle alleles
• New alleles and genetic recombination are the
  source of evolution
• Humans direct and speed evolution by selecting
  only individuals with the most desirable traits
  to breed

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How does geography affect evolution?

• Biogeography geographical distribution of
  organisms
• 6 regions separated by impassable barriers
• Each contains organisms unique to that region

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How is the distribution of organisms determined?

• Climate and other environmental factors affect
  distribution patterns over short periods
  (1000s of years)
• Changes in the positions of the continents occur
  over longer periods (millions of years)
• Continental drift ? plate tectonics
• Pangea ? supercontinent
• 225 million years ago

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• Convergent evolution development of similar
  forms in geographically different areas in
  response to similar environments

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Curriculum Outcomes

• Evaluate current evidence that supports the
  theory of evolution. (316-2)
• Analyse and describe examples where scientific
  understanding was enhanced or revised as the
  result of the invention of a technology (116-2)
• Outline evidence and arguments pertaining to the
  origin development, and diversity of living
  organisms on Earth (316-4).