The Received View of Evolution

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The Received View of Evolution
20.04.2005

• Sex and Death An Introduction to Philosophy of
  Biology

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Contents

• 2.1 The Diversity of Life
• 2.2 Evolution and Natural Selection
• 2.3 The Received View and its Challenges

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2.1 The Diversity of Life

• design space (Dennett, 1995)
• All possible and actual designs
• Regarding these we are highly atypical
• Eukaryotic simply life cycle huge
• Diversity and Disparity (Gould)
• Diversity number of species in existence
• Disparity amount of organisms that have
  fundamentally different designs

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2.1 The Diversity of Life
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• Why are some areas in design space occupied and
  some not?
• Process Structuralists
• Design space is highly constrained
• Historical relativity
• There are so many designs, that there was no time
  to realize them all.

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2.1 The Diversity of Life
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• Why do organisms come packed into species?
• Life without species is possible
• No sharp distinction between spiecies and
  varieties

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2.2 Evolution and Natural Selection

• Basic elements of evolutionary theory (Mayr)
• The living world is not constant
• Evolution. change has a branching pattern
• New species form when a population splits
• Evolution. change is gradual
• Adaptive change through natural selection

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2.2 Evolution and Natural Selection

• Natural selection is the inevitable result of
• Phenotypical variation
• Differential fitness
• Heritability
• Are the forces that induce genetic variation
  deterministic?

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2.2 Evolution and Natural Selection

• Cumulative selection
• Innovation is the result of a sequence of
  selective episodes
• Conditions
• Direction of selection is constant
• Low mutation rate
• Each intermediate stage must be fitter than its
  predecessor (adaptive landscapes)

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2.2 Evolution and Natural Selection

• Speciation
• Cumulative selection in different environments
  results in reproductive isolation
• Hybrid matings will be penalized

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2.3 The Received View and its Challenges

• 3 important debates
• Units of selection
• Selection and evolution
• Evolution within Biology

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2.3 The Received View and its Challenges
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• What is being selected
• genes eye concept (Williams, Dawkins)
• Hierarchical view

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2.3 The Received View and its Challenges

• The genes eye
• Only genes are passed on directly from one
  generation to the next
• Genes are replicators and use organisms as
  vehicles
• Natural selection acts through vehicles and
  targets the replicators
• Problem gene trait relationship

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2.3 The Received View and its Challenges

• Hierarchical view
• organisms are not the only entities that form
  populations (hives, colonies, species)
• Selection can operate simultaneously at different
  levels

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2.3 The Received View and its Challenges

• Selection and Evolution
• Four major issues
• Does the received view overstate the importance
  of adaptation?
• Relationship of selection and other factors
• Methodological issues
• The proper scope of evolutionary explanations

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2.3 The Received View and its Challenges

• The Importance of Adaptation
• ? Fitness advantages only make survival more
  likely !

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2.3 The Received View and its Challenges

• Relationship between selection and other factors
• Selection is historical, it is constrained by
  inheritances of the population
• Some patterns seem to be independent of
  selection
• Evolution after the Cambrian explosion

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2.3 The Received View and its Challenges

• Methodological issues
• How can we test our ideas?
• How much evidence is needed to support a
  hypothesis?

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2.3 The Received View and its Challenges

• Scope of evolutionary explanations
• Sociobiology (Wilson)
• Explaining social / psychological processes with
  evolutionary mechanisms is possible
• vs.
• This attempt is mistaken in principle. Since
  there is culture these rule do not apply to us
  anymore

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2.3 The Received View and its Challenges

• Evolution within Biology
• Evolution and Ecology
• Ecology describes the environment which generates
  selective pressure
• Evolution and molecular Biology
• Genetics did not make Evolutionary Theory futile
• Different levels of explanation