Evolution

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Evolution
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Of course, long before you mature, most of you
will be eaten.
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The pictures pretty bleak, gentlemen. The
earths climate is changing, the mammals are
taking over, and we all have brains the size of a
walnut.
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Now this end is called the thagomizer, after the
late Thag Simmons.
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Evolutions been good to you, Sid.
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Top Ten Myths About Evolution
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1. Humans Evolved From Monkeys

• Humans and great apes had a common ancestor about
  5 million years ago
• Humans and monkeys had a common ancestor about 50
  million years ago

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2. Its Only A Theory

• Theory does not mean hypothesis or guess
• Music Theory
• Stress Theory
• Quantum Theory
• Number Theory
• Theory means an organized set of related ideas.

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3. If Nobody Saw It, We Cant Be Sure It Happened

• If you find your room trashed and your TV and
  stereo missing, will you hesitate to call the
  police because nobody saw it happen?

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4. Science Cant Say Anything About Origins

• Maybe not. But once the origin happens,
  everything after that is history. And historical
  evidence is preserved in the physical record.

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5. Obsolete Concepts

• Survival of the Fittest
• The winner of the Super Bowl is the team with
  the most points.
• What does fittest mean?

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6.There Are No Intermediate Fossil Forms
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7. Evolution Is Not Testable

• Darwin suggested birds had evolved from reptiles
  in 1859 Archaeopteryx was discovered in 1862.
• Piltdown Man
• Famous Early Fossil Man Hoax
• Controversial from the start because it didnt
  match evolutionary expectations.

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8. Evolution Means Humans are Just Animals

• Are you a vegetable or mineral?
• Humans have hair and nurse young just like all
  other mammals
• Traits like nurturing, cooperation and monogamy
  are often favored by evolution because they
  enhance survival of species

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9. Evolution is Just Random

• Is the following number sequence random
  592653589793238462643383279?
• It not only looks random it is random.
• But lacking in meaning? No. These are the digits
  of pi beginning with the fourth decimal place.
• Random does not mean meaningless

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The Scientific Meaning of Random

• Something cannot be predicted with better
  accuracy than that predicted by statistics.
• The phenomenon is its own simplest description

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Randomness and Evolution

• Biological systems are far too complex to
  describe or predict mathematically
• We have incomplete information
• Significant events like climate change or
  asteroid impact are unpredictable.

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10. Complexity Cannot Arise Naturally

• The Second Law of Thermodynamics is often
  paraphrased as
• Things always go from bad to worse
• Disorder in the Universe is always increasing"

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The Second Law of Thermodynamics

• The Second Law is about entropy
• Entropy (Heat Absorbed)/Temperature
• Entropy can decrease locally if it increases
  elsewhere
• Intuitive notions of disorder are of no
  relevance whatsoever

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Chemical Reactions are not Random

• Na Cl Na Cl Na Cl Na Cl Na Cl Na
  Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na
  Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na
  Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na
  Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na
  Cl Na
• Cl Na Cl Na Cl Na Cl Na Cl Na Cl

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Channeled Scablands, Washington
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Scabland Terrain, Oregon
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The Geologic Record

• Physical evidence records mostly small-scale,
  gradual processes
• Fossils show a gradual increase in complexity
  with time
• Fossil forms intermediate between major groups
  are well documented
• Over most of its history, life on Earth was simple

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Were the Dinosaurs Failures?

• Human History 5000 years
• Dinosaurs 150,000,000 years
• Dinosaurs had
• 30,000 years for every year of human history
• 80 years for every day
• 8 hours for every second

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Prebiotic Evolution

• The basic molecules of organic chemistry are
  easily made
• The first self-replicating molecule was almost
  certainly not DNA
• DNA assembles from simpler materials all the time

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DNA

• Deoxyribonucleic acid
• Total length of human DNA in a single cell is
  about a meter
• A human body contains about 20 trillion cells
• The total length of DNA in a human body is thus
  20 trillion meters, or twenty billion kilometers,
  the circumference of the orbit of Pluto.

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Plants and Animals

• CO2 H2O Energy Sugars, Starches, etc. O2
  (toxic waste). O2 is actually toxic (even to us!)
• Idea Take the sugars and starches (from somebody
  else) combine it with the waste O2, and get energy

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Amazing Events in Life History

• Invention of Sex - Who Needs It?
• We are a team - Mitochondria
• The Great Freeze 900-600 m.y. ago
• Mass Extinctions
• Dinosaurs 4th worst
• Permian extinction (220 m.y. ago) took out 90 of
  all species

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Selection

• Deliberate selection for desirable traits by
  humans (only since ca. 1700)
• Unsystematic selection for desirable traits by
  humans (domesticated animals and plants)
• Unconscious and unintentional selection by humans
  (self-domestication of animals)
• Natural selection with no human intervention at
  all

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Lessons from Selection

• Artificial selection has produced organisms
  radically different from their natural state
• Natural selection has resulted in dramatic
  changes in natural populations with and without
  human intervention
• Microorganisms and viruses change with dazzling
  speed (mutation of flu viruses, resistance to
  antibiotics, move to new hosts)

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This Descended from Wolves?
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Evolution By Natural Selection

• Charles Darwin and Alfred Russell Wallace, 1859
• Organisms are adapted to their environments
• Individuals vary
• More organisms are born than can possibly survive
• Variations best suited to the environment tend to
  survive and be passed on.

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Mutations

• Change in DNA code
• If you fix it often enough, youll break it
• Most organisms already adapted
• Chance of random beneficial change small
• Many mutations are neutral
• Radical changes usually harmful
• Mutations may be useful if the rules change

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Radiation

• If no competitors or predators, otherwise harmful
  variations may flourish
• Example loss of flight or sight
• After mass extinctions
• Spread into unoccupied habitats
• Rapid proliferation of variations

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Convergent Evolution

• Unrelated organisms may develop similar features
• Often dictated by physical constraints
• Shark, tuna, dolphin, seal, squid, penguin,
  ichthyosaur
• Deer, pronghorn, impala
• Albatross, pterosaur

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Exaptation

• Modification of existing structure to serve new
  function
• Fin paw wing hand
• Scale feather
• There are no half-formed organisms

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What Good is Half an Eye?
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What Does a Bug See?
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What Does a Bug See?
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What Good Is Half An Eye?

• A partially-developed eye can be very useful
• Selection will favor
• More Receptors (Sharper Image)
• Wider Angular Spread (Better direction
  discrimination)
• Better Image Processing

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What Good is Half a Wing?

• Powered Flight
• Insects
• Birds
• Bats
• Pterosaurs?

• Gliders
• Squirrels
• Lemurs
• Marsupials
• Fish
• Frogs
• Snakes
• Lizards

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Physics of Gliding

• Terminal Velocity
• Air Resistance Gravitational Acceleration
• 200 km/hr for a human
• 20 km/hr for a mouse
• Gliders are All Small
• Can Survive Fall
• Selection favors duration and control

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Two Bumblebee Myths

• Theoretically, bumblebees should not be able to
  fly.
• Bumblebees cant glide well. Neither can many
  aircraft
• A bumblebee can carry more than its own weight,
  something no airplane can do.
• C-5A empty 238,000 lb., maximum takeoff weight
  840,000 lb.

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Classification of Dogs and Humans

• Kingdom Animalia
• Phylum Chordata
• Class Mammalia
• Order Carnivora (Dogs) Primates (Humans)
• Family Canidae Hominidae
• Genus Canis Homo
• Species familiaris sapiens

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Strigiphilus garylarsoni

• Actually, I considered this an extreme honor.
  Besides, I knew no one was going to write and ask
  to name a new species of swan after me. You have
  to grab these opportunities when they come along.

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Below Species

• Ideally, species is a genetic group capable of
  breeding
• Subspecies
• Race
• As used for humans, has little scientific meaning
• Population

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The Five Kingdom System

• Animals
• Plants
• Protista (one-celled organisms)
• Fungi
• Bacteria
• Ediacaran Fossils? (ca. 700 m.y. ago)

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Whats Bigger Than a Kingdom?

• Bacteria differ from all other kingdoms in
  lacking a cell nucleus
• We need a bigger box
• Superkingdoms or Domains
• Monera (Bacteria)
• Archaea
• Eukarya (have cell nucleus)
• Need electron microscopes and molecular biology
  to see differences