17: Predator-Prey Dynamics (Part 2)

Tophat

  • An age structure graph that appears rectangular in overall shape would likely see what in the future?

    • no change in size

  • Which statement correctly identifies the relationship between population size and extinction risk?

    • small populations are most likely to go extinct

  • What is true about the Lotka–Volterra model for predator and prey?

    • The model results in oscillating populations of predator and prey with the predator population lagging behind the prey population.

Chapter 13

Predators and herbivores respond to food availability with functional and numerical responses

  • Type I functional response — A predator’s rate of prey consumption increases in a linear fashion with an increase in prey density until satiation occurs.

    • the more prey, the more the predator consumes

    • simplest relationship

    • doesn’t happen in all predators, happens when predators are really good at capturing prey and consuming them swiftly

  • Type II functional response— A predator’s rate of prey consumption begins to slow down as prey density increases and then plateaus when satiation occurs

  • Type III functional response — A predator exhibits low prey consumption under low prey densities, rapid consumption under moderate prey densities, and slowing prey consumption under high prey densities.

  • One prey present—no alternative prey

  • Two prey present—

Predation and herbivory favor the evolution of defenses

  • Behavioral Defenses

    • Nonconsumptive effects of Brook Trout predators reduce secondary production of mayfly prey Benjamin J. Koch, Robert O. Hall Jr, and Barbara L. Peckarsky Freshwater Science 2020 39:3, 549-558

    • Mayfly defense against brook trout, use smell to detect them

  • Crypsis — Camouflage

  • Structural Defenses

  • Chemical Defenses

  • Warning coloration - aposematism

Mimicry of Chemical Defenses

  • Batesian mimicry

    • When palatable species evolve warning coloration that resembles unpalatable species

  • Müllerian mimicry

    • When several unpalatable species evolve a similar pattern of warning coloration.

    • Batesian