Evolutionary Theory, according to Darwin

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Evolutionary Theory, according to Darwin
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Definitions and Components of Darwins Evolution

• Definition of Biological Change Differential
  Persistence of Variation Now, what does that
  mean? ( AND THIS IS WHAT DARWIN WANTED TO
  EXPLAIN)
• Definition of Evolution Descent with
  Modification.
• And what does that mean?
• Individuals Vary--- (materialism). Only
  variation is real!
• Some variation is inheritable, meaning that some
  observable variation is inherited from our
  parents, and some variation is unique to us.
• Individuals vary in their reproductive success.
  Some individuals leave 10 progeny some
  individuals leave no offspring.
• Differences in reproductive success is known as
• FITNESS. The Individual who leaves 10 offspring
  is, in Darwinian terms more fit than
  individuals who leave only 2 offspring

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So what about Adaptation? What is Adaptation?

• Adaptation is the consequence (or outcome) of
  reproductive success.
• If individuals reproduce and their offspring
  live to reproduce, the parents are by definition
  adapted. Adaptation is a consequence of
  reproducing. And adaptation is closely related to
  fitness.
• Fitness and adaptation are closely related
• If I have 2 children, and you have 10 children
  and all of our children live to reproduce, you
  are by definition more fit and better adapted
  than I am.

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What are the causes (mechanisms) in variation in
reproductive success?

• Natural Selection a concept to Darwin all the
  factors in any setting that resulted in
  differences in reproduction. There are no
  universal selective agents. There are only
  agents that affect reproduction in particular
  historical settings.
• (after Genetics was discovered, genetic drift was
  added as a mechanism of reproductive success)

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SUMMARY

• In contemporary evolutionary science, there are
  two parts to the differential persistence of
  variation
• 1) variation at the scale of individuals.
• 2) Mechanisms of evolution, natural selection
  and drift, operate on that variation so that over
  time, there is differential persistence of
  variation.

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Herbert Spencer Socal Darwinism
Books Principles of Ethics Principles of
Biology Principles of Psychology Principles of
Sociology First Principles of the System of
Philosophy
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Components of Social Darwinism

• Definition of Change Transformation from
  relatively incoherent to relative coherent.
  analogy with organic life higher life forms are
  more complex
• and more coherent than lower life forms
• With transformation, there is an increase in
  coherence and an increase in functional
  specialization.

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Spencers Assumptions

• 1. All life was a single unbroken chain all life
  connected and transformed unlinear one line
• 2.Causes of transformation were inherent to life
  itself.
• (Unlike Darwinism, there were no mechanisms that
  winnowed variation)
• in the 19th Century, this was the doctrine of
  progress
• Inherent directionality to all life that
  transformed from simple to complex.
• The inherent direction was hardwired into
  organisms. Some organisms could progress further
  than other organisms.
• Marriage of biology and culture is the third
  assumption

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SPENCERS CULTURAL EVOLUTION

• Inherent transformation toward greater complexity
  charactized humans
• The phrase for that transformation was survival
  of the fittest . What he meant by that phrase
  was a kind of natural transformation driven by
  the inherent nature of humans.
• The phrase was misinterpreted with natural
  transformation equated with good. Those most
  capable of transformation survive.
• Became a justification for the scaling of
  societies from simple to complex in the 19th C.
• Darwin liked the phrase and said that in the
  context of natural selected it explained
  adaptation. Survival of the fittest explains
  differential persistence of variation

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Contrast between Darwin and Spencer
Darwin Spencer
Evolution Descent with Modification Transformation
Components Variation And selection
Cause Mechanism natural Selection Internal hard-wired
Description of evolution change Bush Single line
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20th Century Anthropological EvolutionNeo
Evolution
Julian Steward
Leslie White
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Leslie White

• Major assumption human cultural development is
  unique. We need unique laws to explain it.
• Evidence of uniqueness language, symbolism
• Cultural laws must explain cultural evolution
• Influences on his Intellectual framework Spencer
  and Marx
• From Spencer
• cultural development really is progressive. Human
  cultures develops from simple to complex.
  Progess is a fact!
• The development of culture is unilinear one
  large trunk
• From Marx
• Fundamental to understanding cultural change is
  economics or the modes of production. Modes of
  production underlie all other changes.
• Science was the was of understanding and
  explaining those changes.

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Leslie White (cont)

• How he modified and used his intellectual guides
• 1. Progress was inevitable but no hard wired
  into the species. No inherent principle to
  humans that resulted in greater complexity. AND
  no value placed on greater
• complexity. It simply is.
• 2. Causes of development are material. They
  are to be found in the material conditions of
  life, economics, technology, etc.

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Whites Cultural Laws

• Law of Evolutionary Development C E x T
• C culture E energy capture or efficiency
  (technology) T time. (this is technology)
• Examples unilineal transformation from Bands to
  Tribes to chiefdoms to state
• Law of Cultural Dominance cultures that exploit
  energy more efficiently in one environment will
  spread at the expense of the less efficient.

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Julian Steward Multilinear Evolution

• Major premise Culture change occurs because of
  the interaction between environmental setting and
  people in that setting. Steward is the beginning
  of cultural ecology in Anthroplogy.
• Setting places constraints on the choices that
  individuals make.
• Environment a broad definition, including
  terrain, soils, resources, and other social
  groups
• AND The same cultural expression can occur in
  vastly different settings if the constraints are
  the same
• development of Bands in the Arctic and in the
  Great Basin

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Steward (cont)

• Culture Core that part of a culture that
  relates people to their setting So, to Steward
  it was the culture core that linked people to
  their setting and was the basis of the cultural
  expression.
• "the constellation of features which are most
  closely related to subsistence activities and
  economic arrangements" (Steward 195537). 
• Differences from White
• Culture change is not linear or progressive.
  Change is locally determined by the setting and
  the essential features that relate folks to that
  setting.
• Technology does not drive culture change
  interaction between organisms and their setting
  drive change.

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Critique of Neo Evolution from both scienitsts
and post-processualists

• culture evolution is not unique
• lineal sequence does not address the range of
  variation in societies
• post processualists argue that NE ignores people
  and fails to consider the variation within
  societies.
• Neo evolution does not allow for contingency

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Contemporary Archaeological Evolutionary Ideas
Laura Betzig
Virginia Butler
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Selectionism and Evolutionary Ecology

• Commonalities
• Both proceed from a platform of science. Building
  knowledge is the goal answering WHY questions
• Actively building theory. In fact, both have
  theory, and that theory is Darwinian Evolution
• Consequently Darwinian principles and mechanisms
  apply individuals vary, heritable variation,
  reproduction matters, mechanisms operate on and
  winnow variation resulting in differential
  persistence

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Selection operates on the Phenotype What is the
phenotype?
Menstral Hut
Bower Bird
Male Peacock
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DIFFERENCES

• Selectionism Goal is to explain the
  archaeological record ARTIFACTS in evolutionary
  terms
• Human Evolutionary Ecology explain human
  behavior in evolutionary terms. Use evolutionary
  principles to account for human behavior
  foraging strategies, mating systems, birth
  spacing

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Selectionism ( Robert Dunnell)

• Key Components of his Ideas materialism,
  archaeology as an historical science and
  explanation
• Artifacts are the focus of explanation Why new
  forms, technologies evolve?
• Artifacts are part of the human phenotype.
  Therefore selection operates on artifacts
• Connect artifacts to two step evolutionary
  process
• Produce variation winnow variation

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Methodology of Selectionism

• Style those artifact traits that do not
  contribute to reproductive success
• Function artifact traits that contribute to
  affect reproductive success
• Mechanisms
• Selection operates on functional traits, and
  those traits show directional changes in
  frequencies over time (selection operates on
  functional traits)
• Drift random changes in gene frequencies
• (drift operates on stylistic traits)

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Frequency
Function
Frequency
Style
Time
Shape of Stylistic versus Functional Trait
through time
Time
Shape of selection curves operating on two
alternative functional traits over time
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How Operationalize?

• Select artifact traits to measure forms,
  technology, attributes--- like corner and side
  notching
• Must be able to measure artifact traits over
  time have to have the temporal dimension
• Count frequencies over time and construct curves
• Curve shapes tell you whether
• Selection or drift is occurring
• This is an evolutionary description
• The WHY in evolutionary terms

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Critique of Selectionism

• Well do this together