Adaptation

1
Chapter 2

• Adaptation Evolution

2
Adaptation Natural Selection

• The differential success of individuals resulting
  from their interaction with the environment.
• Darwin numbers game
• Two conditions
• Variation of heritable characteristic
• Characteristic results in differences in survival
  reproduction
• Fitness

3
Natural Selection

• Directional selection favors extreme
• Stabilizing selection favors population mean
• Disruptive selection bimodal distribution

4
Measures of evidence for natural
selectionFavorable environmental conditions
favors allUnfavorable conditions most
selective
5
The Origin of Species

• Charles Darwin
• Characteristics passed on to next generation
• Characteristics may change through time

6
Units of inheritance
Chromosomes Genes Alleles alternate Locus
location Homo/heterozygous
7
Plasticity

• Variation of the same structure
• Same genetic makeup different expression
• Response to environmental conditions

8
Natural Selection

• Mutation abrupt increase in genetic variation
• Geographical isolation genetic isolation
• Individual ? population ? subpopulation
• Sympatric occupying same area
• Allopatric separated by time or space
• Sympatric vs allopatric speciation

9
Adaptation

• Response to environmental gradient
• Environmental Tolerance
• -Minimum tolerance limit
• -Maximum tolerance limitGrowth?
  Reproduction?--or just survival?

10
Law of Tolerance

• - limiting factor or condition and presence and
  success of an organism in these conditions
• 1. One limiting factor --chemical,
  physical, or biotic 2. Adaptations/ specialized
  features --mouthparts, appendages,
  digestive system
• --location of stomata, thickness of
  cuticle