Applied Evolution: Why Engineers Need to Understand Biological Evolution

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Applied EvolutionWhy Engineers Need to
Understand Biological Evolution

• Dr. Donald L. McEachron
• School of Biomedical Engineering, Science and
  Health Systems

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Purpose of Engineering

• To Improve Human Condition through Enhancements
  in Human Health, Well-Being and Productivity

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All Engineering is By Humans for Humans

• Critical to Understand Human Reactions/
  Capabilities
• Failure To Design with Human Characteristics in
  Mind
• Control Systems Failures
• Costs in Terms of Systems Failures
• Waste of Personal and Financial Resources

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Propositions

• To Control Something, First it is Necessary to
  Understand It
• To Understand Something, You Must Know Its
  Character
• To Understand the Character of Something, You
  Should Understand Its Function

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Human Case

• Do Humans Have a Fundamental Character?
• i.e., Is there a Human Nature?
• Do Humans Have a Function?
• Ultimate Function?
• Proximate Function?

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Partial Answer Biological Evolution

• What is Biological Evolution?
• Definition A Change in the Inheritable
  Characteristics of a Biological Population over
  Generations
• Not a Hypothesis or Theory, but rather an
  Observation

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Mechanism

• Random Mutation - Source of New Material
• Natural Selection - Non-Random Filter

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Darwins Proposal

• Organisms Can and Do Produce More Offspring Than
  Survive
• Survival and Reproductive Capabilities Depend in
  Part on Inherited Traits
• Therefore, Successful Traits will Increase and
  Unsuccessful Traits Decrease over Generations

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Dawkins Version

• Stable Entities last Longer than Unstable Ones
• Informational Stability is the Persistence of
  Information by Making Copies
• Genes contain Information whose Stability depends
  on Replication
• Natural Selection Informational Stability

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Conclusions

• Ultimate Function of All Living Organisms is the
  is the Preservation and Propagation of Genetic
  Material
• All Organisms, including Humans, are Machines
  created through Mutation and Natural Selection to
  Preserve and Propagate Genetic Material

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Implications

• Opportunistic - Not Always Expected Results
• Gene Favored, Not Organism
• Selection Among Pre-Existing Variants
• Inefficient - May Require Considerable Time
• Historical - Past Results Influence Future
  Directions
• Delayed Adaptation - Organisms Best Adapted to
  Ancestors Environment

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Evolutionary Thinking

• Failure - Antibiotic Resistance
• Success - Seasonal Affective Disorder
• Potential - Sudden Infant Death Syndrome

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Antibiotic Resistance

• Failure of Physicians and Patients to Appreciate
  Evolutionary Potential of Microbes Lead to
  Overuse
• Excessive Use of Antibiotics Selected for
  Resistant Strains
• Tuberculosis, Gonorrhea, Malaria Treatment
  becoming More Difficult
• Strains becoming Multi-Agent Resistant

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Alarming Statistics

• Some 2 million patients/year getting infections
  in hospitals (CDC) some 5-10 of all admitted
  patients (New England Journal of Medicine)
• Deaths from Hospital Infections has risen from
  13,300 in 1992 to over 90,000 in 2004 (CDC)
• S. aureus Infections Resistant to Methicillin are
  Endemic in Hospital and Increasing in General
  Population
• Vancomycin-resistant Infections are Increasing

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The Katrina Effect

• Failure to Anticipate Consequences of Activity
• Flood control measures diminish delta
• Overpopulation along coasts increase numbers at
  risk
• The Resistance Time Bomb
• Overuse of antibiotics selects for resistance
• Initial successes lead to complacency
• High population density and efficient
  transportation network increase potential for
  pandemics

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Seasonal Affective Disorder

• Seasonal Depression
• Both Winter and Summer Versions
• Winter More Often Diagnosed
• May be Very Common
• Following Slides from
• http//www.medscape.com/viewprogram/4316_pnt

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Conclusions

• Humans Show Residual Photoperiod Sensitivity
• Historical Hibernation or Migration Response?
• No Need to Return to Hominid Lifestyle
• Re-engineer Present Environment to Mimic
  Necessary Conditions

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SIDS - Sudden Infant Death Syndrome

• In 1969, researchers agreed to define sudden
  infant
• death syndrome (SIDS) as "the sudden death of any
  
• infant or young child, which is unexpected by
  history,
• and in which a thorough postmortem examination
  fails
• to demonstrate an adequate cause for death"
  (Bergman,
• 1970).

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Risk Factors

• According to the National Institute of Child
  Health and Human Development (NICHD), the
  incidence of SIDS is greatest in infants younger
  than 6 months of age and increases during cold
  weather. African-American infants are two times
  more likely to die of SIDS than white infants,
  and Native Americans are about three times more
  likely than whites. More boys than girls fall
  victim to SIDS. Other potential risk factors
  include
• smoking, drinking, or drug use during pregnancy
• poor prenatal care
• prematurity or low birth-weight
• mothers younger than 20
• smoke exposure following birth
• stomach sleeping
• http//kidshealth.org/parent/general/sleep/sids.h
  tml

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Observations

• Considerable cultural differences in incidence of
  SIDS Where other risk factors controlled,
  (maternal smoking, etc.), co-sleeping correlates
  to lowered SIDS
• Cross-species studies of apes/monkeys show
  considerable distress at separations for periods
  as little as 3 hours

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Observations

• Clinical studies show that skin-to-skin contact
  has positive physiological effects on pre-term
  infants and neonates
• SIDS research indicates that SIDS risk is reduced
  by
• Increased breast-feeding frequency and duration
• Avoiding prone sleeping posture

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Hypothesis

• Hominids evolved with mother-infant co-sleeping
  and thus co-sleeping is the normal pattern.
  Isolation of the sleeping infant is an abnormal
  pattern induced by cultural biases which may
  actually increase the risk of
• SIDS

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Initial Testing

• Study by McKenna, Mosko and Richard (1999)
• 1. Two Groups Examined
• a. Mother-infant co-sleeper
• b. Solitary sleepers
• 2. Both Groups Examined when Co-sleeping and
• when Solitary sleeping
• 3. Measures taken
• a. EEG
• b. Sleep behavior/Interactions
• c. Breast-feeding

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Preliminary Results- Sleep EEG

• Infants
• Show more Stage 1-2 and less Stage 3-4 when
  co-sleeping vs. solitary
• Effects greater in normally co-sleeping vs.
  normally solitary
• No effect on REM
• Increase in number of arousals per night

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Preliminary Results- Sleep EEG

• Mothers
• Similar reduction in SWS Increase in Stage 1-2
• No change in REM
• No change in TST
• Increase in number of arousals

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Observations on Arousals

• Infant arousals selectively increased from Stage
  3-4
• Maternal arousals increase 3 fold by co-sleeping
• Greater effects in normal co-sleepers vs. normal
  solitary sleepers
• Most often in response to infant arousal

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Considerable amount of affection
interaction/touching/talking when co-sleeping
none when solitary sleeping
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Breast-Feeding

• Breast-feeding is twice as frequent in
  Co-sleepers
• Co-sleeping infants breast feed 3X longer per
  night vs. solitary sleepers

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Disturbing Questions

• ARE WESTERN CULTURAL NORMS HARMING NORMAL INFANT
  DEVELOPMENT/ BEHAVIOR?
• McKenna, et al observation A crying infants
  crying upon separation an adaptive mechanism to
  ensure maternal attention and ability to locate.
  Thus crying is normal NOT crying (the cultural
  objective) is evolutionarily ABNORMAL

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The Proximate Dilemma

• Evolutionary Hypotheses based upon Ultimate
  Function Limited
• Need to Know Specifics of Hominid Evolution
• What is the human brain really for?
• What did the brain evolve to accomplish?