Evolutionary innovations can induce adaptive radiation
o angiosperms use animals as pollinators
o different pollinators -> reproductive isolation
What's in it for the bird?
o nectar, food
When two species interact...
o Both may benefit: Mutualism
o Both may suffer: Competition
o One may benefit at the expense of the other: anatgonism
Evolutionary arms race
o adaptation by species A improves its ability to interact with species B
o selection pressure on B to evolve counter-adaptation
o selection pressure on A to evolve counter-counter-adaptation
Improved equipment =/= improved success
Who wins the arms race?
o may keep escalating until costs outweigh benefits
Red Queen equilibrium
o sometimes, one side has the advantage
strength of selection
o prey need to run for their lives, if got caught, they're dead
o predator just don't get to eat, if does not catch a prey
Arms races between mutualists
Back to antagonism... Host-parasite relationships
o Parasite gets resources at the expens