coevolution

• Co-Evolution

  When two or more species act as reciprocal selective agents/forces on one another

  
• Coevolution


  When two or more species act as reciprocal selective agents/forces on one another
• Coevolution


  1. Species 1 selects on traits of Species 2

  2. Species 2 selects on traits of Species 1
• Coevolution


  • The biota acts as a selective pressure on itself
  • Distinct from abiotic selective pressures
  • The selection must be reciprocal
  • The species act as selective agents on each other
  • Unlike most abiotic selection agents, there can be feedback in the system
  • Adaptation in response to species 1 can lead to selective pressure for new adaptations in species 2
  • And vice versa
• Coadaptation


  Mutual adaptation of two species to one another
• Positive (mutualism) coadaptation


  A coadaptive relationship where two or more species experience increased fitness from mutual adaptations
• Negative (antagonistic or arms race) coadaptation


  A coadaptive relationship where one species experiences increased fitness, but the other experiences decreased fitness
• Ant-plant mutualism


  • Pseudomyrmex ants and some tropical Acacia trees
  • Acacias benefit ants by providing swollen thorns for shelter
  • Acacias benefit ants by providing Beltian bodies for food
  • Ants benefit the trees by defending them against herbivores and diseases
  • an example of positive co-adaption
• Testing the Effects of Ants

  1. Girdle some trees with Tanglefoot

  2. Assess damage on control trees and ant-free trees