Chapter 5 Outline

Natural Selection and Evolution in Real Time

Evolution by Selection and Inheritance

Fitness: The Currency of Selection

Positive Selection: The Spread of Beneficial Mutations

BOX 5A Evolution by Selection on a Single Locus

  • The rate of adaptation
  • Chance and adaptation: The probability that a beneficial mutation spreads

Evolutionary Side Effects

  • Hitchhiking: When one allele goes for a ride with another

When Selection Preserves Variation

  • Overdominance
  • Other forms of balancing selection

Selection That Favors the Most Common

  • Underdominance: When heterozygotes suffer
  • Positive frequency-dependent selection

The Evolution of a Population’s Mean Fitness

  • The fundamental theorem of natural selection and the adaptive landscape

Deleterious Mutations

  • A mutation-selection balance
  • The mutation load