Evolutionary modeling: a debate on its application to biological and nonbiological systems

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Evolutionary modeling a debate on its
application to biological and non-biological
systems

• ByHussam R. Okasha Alan L. Stottlemyer

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Part I Evolutionary Biology

• Introduction
• Darwins Theory of Evolution
• Natural Selection
• Evidence of Natural Selection
• The Mathematical Theory of Games and Biological
  Systems

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Scientific Climate During Darwins Time

• Geologists were studying layers formed by the
  deposition of sediments.
• Uniformitarianism- determining the age of Earth
  by understanding present conditions.
• Fossil Discoveries- the deeper the strata, the
  less similar fossils one will find to existing
  species.
• Similarities among groups of differing species
  were considered evidence of evolutionary change.
  
• Jean-Baptiste Lamarck- proposed organic evolution
  as an explanation for the physical similarity
  among organisms and even proposed the inheritance
  of acquired traits as the mechanism for the
  adaptive change.

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Darwins Voyage

• Observations made at the Galapagos Islands on the
  survey ship Beagle.
• Took note of slight variations between organisms
  on different islands.
• Famous Darwin finches, a group of birds on the
  islands.
• Observations inspired his book On the Origin of
  Species (1858).
• Book addressed scientific problems during
  Darwins time.

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Darwins Theory of Evolution

• General Change- Organisms have changed over a
  long process of time where many organisms have
  been extinct in the process.
• Branching Process- All organisms are derived from
  previous organisms, two organisms were similar
  because they inherited a shared trait from their
  common ancestor.
• Speed of Change- will always act very slowly,
  often only at long intervals of time, and
  generally on only a very few inhabitants of the
  same region at the same time. Darwin
  -Supported by fossil record, however new studies
  have shown that evolutionary process is occurring
  at smaller intervals with time.
• Natural Selection- popularly known as survival
  of the fittest, as the process in nature by
  which only the organisms best adapted to their
  environment tend to survive and transmit their
  genetic characteristics in increasing numbers to
  succeeding generations while those less adapted
  tend to be eliminated.

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Natural Selection According to Darwin

• Natural Selection- preservation of favorable
  variations and rejection of injurious variations,
  occurs when a change in the condition of life
  takes place.
• Sexual Selection- the selection of female
  characteristics by males in order to produce
  offspring.
• Circumstances favorable to natural selection
  -Reduced intercrossing, isolation, and number
  of individuals
• Factors Affecting the Speed of the Process
  -Geographic change is very slow -Mutual
  modifications arise in a slow process
  -Intercrossing hinders the process
• Extinction- inevitable process, due to natural
  selection, number of a specific species increased
  as others decrease.
• Divergence of character- diversification allows
  more resources to be utilized, which increases
  chance for survival.

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Process of Natural Selection
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Geneticist Definition of Natural Selection

• Differential reproduction of genotypes.
• In order for natural selection to occur
  -heritable variation for some trait
  -differential survival and reproduction
  associated with the possession of that
  trait
• Natural selection can only choose among existing
  varieties in a population.
• Variations occur due to random processes in
  genes, rather than by necessity.

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Types of Selection

• Stabilizing selection- acts against extreme
  traits and favors the more common intermediate
  variants. -Reduces variation and maintains
  a particular character trait
• Directional selection- favors individuals on one
  end of a trait range, common during periods of
  environmental change.
• Diversifying selection- favors individuals on
  both trait extremes over intermediate variants
  (rarest of the modes).
• The selection of traits favored along a range of
  individual variations determines each selection.

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Evidence of Natural Selection

• Darwin Finches- Each island had its own type of
  finch, different from the one found on the
  mainland of Ecuador. -each finch
  adapted its beak for a different purpose
  -shows each finch adapted to its
  environment via natural selection
• Industrial Melanism- phenomenon that affected
  over seventy species of math in England during
  the Industrial Revolution. -Prior to
  1800, the typical moth had a light
  pattern, where dark moths were rare
  -Industrial wastes darkened trunks and by 1886,
  the dark-colored moths became very common
• Illustrates adaptation by natural and rapid
  evolutionary change, thus questioning the
  apparent strength and speed of natural selection.

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The Mathematical Theory of Games and Biological
Systems

• Game theory- study of decision problems in
  competitive situations.
• Analysis of games in order to derive rules for
  making decisions when two or more players are
  competing for the same objective. -game
  a situation where participants compete to
  achieve some objective within a given set of
  rules
• Concepts can be applied to biological systems,
  where species and/or genes are treated as
  players.
• Evolutionary Stable Energy- Hawk-Dove game
• Strategies can be described as pay-off functions
  for the hawk and dove.
• Consistent with analysis by natural selection,
  explains more subtle, evolutionary topics.

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Hawk-Dove Game

• Two individuals compete for a resource,
  characterized as an increase in the Darwinian
  fitness of the individual who obtains the
  resource.
• Hawk Initiate aggressive behavior, not stopping
  until injured or until one's opponent backs down.
• Dove Retreat immediately if one's opponent
  initiates aggressive behavior.
• Determining which strategy is evolutionary stable
  as pay-off functions.

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Summary

• Natural selection and game theory has given
  excellent insight into many biological processes.
• Evolution has been unfairly discarded from
  popular knowledge, without scientific argument
  for rejecting the theory.
• Creationism and evolution debate has forced
  courts to determine the constitutionality of
  whether teaching either theory is appropriate in
  schools.
• Epperson v. Arkansas- Supreme Court found that
  Arkansas law prohibiting the teaching of
  evolution was unconstitutional because the
  motivation was based on a literal reading of
  Genesis.
• Only until evolution is recognized as a science,
  instead of wild speculation, can a logical
  compromise exist between the two ideas.

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Part II the modeling of non-biological systems

• Natural Selection Highlights
• Cultural Evolution
• Language Evolution
• Scientific Evolution

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Natural Selection Highlights

• Key to natural selection is FITNESS
• Mainly reproductive
• Occurs because of random mutations
• Genetic information passed down through genes
• Memes first widely published by Dawkins in 1976
  The Selfish Gene
• Meme non-tangible equivalent of a gene
• Allows information exchange through generations
• Used in non-biological modeling
• Mimetics modeling using memes

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Cultural Evolution

• Two trains of thought
• Direct biological analog
• Cumulative Development of Stages learning by
  a means of acquired stages is acquired by an
  individual in the same manner the theory was
  developed.
• Addition/Subtraction Multiplication/Division
  algebra geometry calculus
• Mimetic analog
• Meme is slight variation in recipe
• Baking a cake dance forms
• Vulnerability of Cultural Evolution
• Burn our libraries, smash our computers, and
  stop all teaching for just one generation break
  just a link in the chain of transmission and
  its all gone, only to be regained, if at all,
  after a long process of carefully building
  innovation upon innovation. Carel van Schaik

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Language Evolution

• Noam Chomsky concept of universal grammar
• Concept of poverty of stimulus
• Biological Analog reproductive advantage from
  good communication
• Function of brain capacity

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Language Evolution Cont.

• Language exists to further its own existence in
  its environment -gt brain
• Mimetic Analog meme represented by the word
• non-obligate mutualistic endo-symbiant Morten
  Christianson (Cornell)
• Arbitrary character of words
• Distortion of word meaning
• Homine -gt Hombre spanish, Uomini italian,
  Homme French

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Scientific Evolution

• Biological Analog science hands down information
  through generations
• Mutations product of human imagination
• Peer review selection process
• Mimetic Analog meme is scientific concept
• Easily understood, yet complex concepts easily
  persist
• Ex. Gravity, Newtons Second Law

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Engineering Relevance

• Biological Application
• Medical technology requires an intricate
  knowledge of mans anatomy and past
• Non-biological Application
• Importance of understanding of instantaneous
  changes
• Calculus invented by Newton
• Now need to understand slow changes to move to
  longer time scales
• Game theory being developed based on Natural
  Selection

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Conclusion

• Importance is not in the solutions, but in the
  questions that solutions generate
• Stimulate scientific thought
• No need to answer if science SHOULD take this
  approach
• Science IS taking this approach
• One learns as much from failure as from success