Evolution of Evolution

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Evolution of Evolution

• What is evolution?
• What was going on this time period?
• Who influenced the idea of evolution and how?
• What is natural selection?
• How did giraffes get such long necks?

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Darwins Theory of Evolution

• Evolution process by which modern organisms
  have descended from ancient organismsCHANGE OVER
  TIME
• Scientific Theory well-supported testable
  explanation of phenomena that have occurred in
  the natural world

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Time Period Most Europeans Believed

• Earth was only a few thousand years old.
• The world was geometrical and regimented and will
  never change.
• Rocks, mountains, etc were created by
  catastrophic events that were rarely witnessed.

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Influences

• Carl Linneaus
• If he could fine the pattern in nature he could
  get inside of Gods head.
• Classified flowers into groups based on
  anatomical differences
• Believed that the Earth was complete no gaps,
  no failures
• Buffon
• Was there a separate creation for each variety?

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Influences

• William Smith
• Believed that things had changed since creation
• Hypothesized that different animals lived at
  different times

• Georges Cuvier
• Used comparative anatomy to create replicas of
  extinct animals in which only a few fossils were
  found
• Hypothesized that animals became extinct due to
  catastrophes in historyBUT what about humans??

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Influences

• William Buckland
• People were not wiped out by catastrophes because
  they were not there.
• A giant flood seemed to explain all of the
  unexplainables. BUT why were many fish killed
  off?
• George Stroke
• Volcanoes and old lava being cut through by
  rivers was more evidence that Earth is older than
  the Bible predicts.

• George Hutton
• Wind and water erosion take a very long time,
  thus the Earth must be older than the Bible
  predicts.

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Lamarcks Evolution Hypothesis

• One of the first to realize that living things
  changed over time

• Hypothesis
• By selective use or disuse of organs, organisms
  acquired or lost certain traits during their
  lifetime. These traits (acquired or not) could
  be passed down to their offspring. Over time,
  this process led to a change in species.

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Lamarcks Evolution Hypothesis

• Tendency Toward Perfection
• All organisms have an innate tendency toward
  complexity and perfection. Organisms will
  continually change and acquire features that
  bring them closer to this goal.
• Use and Disuse
• Organisms could alter the size or shape of
  particular organs by using their bodies in new
  ways.
• Inheritance of Acquired Traits
• Acquired characteristics could be inherited.

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Lamarcks Evolution Hypothesis Incorrect in
Several Ways

• Did not know how traits were inherited
• Did not know that an organisms behavior had no
  effect on its heritable characteristics

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Influences

• Charles Lyell
• Hypothesized that geological processes were the
  same as they were in past as they are now
• The rate at which things changed was very slow.
  Thus, in order for all of these slow processes to
  have taken place, the Earth must be older than a
  few thousand years.
• Principles of Geology
• Very influential to Charles Darwin

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Influences

• Thomas Malthus
• The population had the potential to grow at a
  rate faster than food could be supplied. If the
  population kept growing at this rate,
  overpopulation was imminent unless reproduction
  and/or survival was stopped.

Struggle for Existence
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Charles Darwin
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Travels Voyage of the Beagle

• Charles Darwin sailed around the world via the
  H.M.S. Beagle from 1831-1836
• Collected plant and animal species
• Read latest scientific books (i.e. Lyells
  Principles of Geology)
• Recorded his observations and thoughts throughout
  journey

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Galapagos Islands
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Observations

• Many plants and animals seemed remarkably
  well-adapted to their environments.
• Puzzled by where different species lived and did
  not live
• If Earth could change over time, couldnt life
  itself change over time?
• Drew connections between Malthus work and his
  observations of plants and animals
  Malthus argument was stronger for plants and
  animals than for humans.
• An overwhelming number of offspring die, while
  only a few surviving offspring succeed in
  reproduction.
• http//www.pbs.org/wgbh/evolution/library/02/5/l_0
  25_01.html

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Charles Darwin Artificial Selection

• Artificial Selection nature provided the
  variation, and humans selected those variations
  that they found useful
• Examples farmer breeds his best livestock
• Darwin artificially selected pigeons to show an
  analogous example of how his mechanism for
  evolution could have worked.

• Reasoned that nature, given more than a million
  years, could surely achieve what he had
  artificially achieved in a short amount of time.

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Influences

• Alfred Russell Wallace
• Collected beetles along the Malaysian coast and
  noticed variations in the beetles that
  corresponded with the habitat in which they were
  found
• Made some conclusions and wrote a letter to
  Charles Darwin

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Conclusions On the Origin of Species

• Proposed natural selection (mechanism for
  evolution)
• Presented evidence that evolution has been taking
  place for millions of years
• Driven to publish his theory came from the fact
  that Wallace had come up with the same idea.
• Even though he was afraid of the Churchs
  reaction to his ideas he wanted to get credit for
  his work.
• http//www.pbs.org/wgbh/evolution/library/11/2/e_s
  _2.html

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Darwin v. Lamarck How did giraffes get such
long necks?