6.4 evolutionary consequences of predation Flashcards
what is coevolution?
-predators exert a selective pressure on prey: any characteristic that enables individual prey to avoid being detected and captured by a predator will increase its fitness
-natural selection should: function to preserve “smarter more evasive prey and produce “smarter” more skilled predators
-coevolution: as prey species evolve ways to avoid being caught, predators evolve more effective means to capture them
what is the red queen hypothesis of coevolution?
“now, here you see, it takes all the running you can do, to keep in the same place”
-for prey to avoid extinction at the hands of predators, they must evolve means of avoiding capture
what is exploiter-prey coevolution?
-an individual exploiter that successfully eats prey is more likely to survive and reproduce
-a prey individual that successfully avoids being eaten by an exploiter is more likely to survive and reproduce
-very strong evolutionary pressure on prey (so very cool adaptations)
what is mullerian mimicry?
the similar colour pattern shared by many unpalatable or venomous species
-this is effective because the predator has to be exposed to only one of the species before learning to stay away from all other species with the same warning colour patterns
what is batesian mimicry?
occurs when an edible species mimics the inedible or dangerous species (the model)
-mimicry is not limited to color pattern (ex: rattle-like sounds of burrowing owl)
what is an example of defensive thorns?
kapok tree
what is a defense of dandelion?
dandelion secondary defense: latex chemical defense
what is the snake example of batesian mimicry?
what is primary prey defense strategies?
serve to prevent the exploiter from ever finding the prey (camouflage=crypsis)
-can hide from their predators and/or their own prey they are hunting
-examples are: zebras and painted frogfish
what is secondary prey defense strategies?
often draw attention to the prey but also send a message that deters the exploiter from attacking
-may project the appearance of a big eyed predator, mimic other species
-fools into thinking it is dangerous, but sometimes they are actually dangerous
-aposematic coloration (warning coloration) like contrasting colors almost always signal danger
-examples: elephant hawk moths have markings that look like eyes, herbivorous ants that appear more dangerous, bees and wasps have alternating colors
-also thing such as defensive spikes (pufferfish, sea anemones, porcupines)
what are tertiary prey defense strategies?
help the prey escape or fight back if the predator does attack
-ex: fleas jumping, fish leap out of water
-can also stay in place: like turtles (hard covering), playing dead
-swarming, sacrifice (dangle away from head and vital organs) making attack less deadly
-sea stars shed limbs and amphibians shed tails
-can also just fight back
