Coevolution

Mutualism

• Both species benefit from the interaction
• Removal of one species has detrimental effect on other
• e.g. mycorrhizae

Commensalism

• One species benefits, the other is unaffected
• Removal of beneficial species has detrimental effect on other, but not vice versa
• e.g. epiphytes on tropical trees

Parasitism

• One species benefits at the expense of another
• Removal of parasitic species has beneficial effect on host
• Loss of the host (prior to reproductive cycle) has detrimental effect on parasite
• Frequently not fatal, but can weaken host response to other stresses
• Parasites that trigger disease and death called pathogens
• e.g tapeworm, crown gall bacteria

Predation

• One species consumes the other (or most thereof)
• Capture prey through pursuit and ambush
• Consumers are predators

Evolutionary arms race

• Deterrence
  • Impose (or imply) cost on potential predator
  • Bright, bold coloration frequent
  • Mimicry by freeloaders
  • e.g. hornet, cacti, Monarch Butterfly
  • Predator adapts through physiological or behavioral changes
• Avoidance
  • Avoid detection by potential predator
  • Cryptic coloration frequent
  • e.g. Potoo, Walking Stick
  • Predator adapts through sensory or behavioral changes
• First predator to adapt gains competitive advantage

Asian Giant Hornet

Nopal(?) Cactus

Monarch Butterfly

Potoo

Walking Stick