Predatorprey relationships Predation is a straightforward interspecies population

Predator-prey relationships

Predation is a straight-forward interspecies population interaction. One species uses another as a food resource. Predators play an important role in controlling prey population numbers in some systems. In simple systems, the predator-prey relationship results in coupled population osscilations

Classic example of predator-prey dynamics: Canadian lynx & snowshoe hare Coupled oscillation

• prey numbers increase, predator numbers increase…to a point where the predation causes population decline in the prey item. .

Tactics of the Predator 1) Invisibility Cloak (cryptic coloration/ camouflage) http: //www. youtube. com/watch? v=__XA 6 B 41 SQQ

Tactics of the Predator 2) Patience is a Virtue (Hide and Wait)

Tactics of the Predator 3) Death by Poisoning (Venoms)

Tactics of the Predator 4) “Right this Way Please”: trap-doors, nets, and other deadly devices.

Tactics of the Predator 5) Bigger, Badder, Faster 200 mph 700 lbs & built to kill What immortal hand or eye Could frame thy fearful symmetry? William Blake http: //www. youtube. com/watch? v=DWs. N 63 PRCW 8 17, 000 lbs, and perhaps as smart as you

Tactics of the Predator Combinations- Invisibility Cloak; Patience; Bigger, Badder, Faster Dr. Laurie Marker: Dropped out of school at 20, tried to start a vineyard- discovered that wildlife conservation was her life passion, became world renown expert. www. cheetah. org

Responses of the Prey 1) Invisibility Cloak (cryptic coloration/ camouflage)

Responses of the Prey 2) FLEE!!!!

Responses of the Prey 3) Eat me and die (poisons and aposematic coloration):

Responses of the Prey 4) “Shields up”: (armor):

Responses of the Prey 5) “Who wants fetid flesh for dinner? Surely not a proud hunter like yourself” (play dead):

Responses of the Prey 6) Mimicry: Batesian mimicry- looks like a toxic model- but is non-toxic Mullerian mimicry- looks like a toxic model- AND is toxic

Responses of the Prey 6) Disguise:

Responses of the Prey 6) Strength in Numbers:

Herbivore-plant relationships also can evolve into an “arms race” Plants evolve armor (thorns, spines, prickles), toxicity, implant cells with silica, and sometimes symbiotic relationships to defend foliage.

Plants evolve thorns, animals evolve morphology and behavioral techniques to avoid thorns. Plants get taller, change canopy structure, animals get taller.

The expense of herbivore defense is only worth it if the foliage is very valuable. Plants that live it harsh conditions, can’t afford to rebuild foliage, so develop defenses. Plants that grow in lush conditions, simply outgrow herbivores.