Predator/prey interactions Flashcards
Describe the roles of predators and prey in the evolutionary arms race
Predators- selection for improvements in foraging
Prey- selection for improvements in defences.
Describe the “red queen hypothesis’
/all the running you can do just to stay in the same place’
organisms must constantly adapt, evolve, and proliferate not merely to gain reproductive advantage, but also simply to survive while pitted against ever-evolving opposing organisms in an ever-changing environment
Give an example of an evolutionary arms race between predator and prey
Insects and bats
Bats= echolocation to detect insect prey
Insects= tympanic ears can hear ultrasound. (beetles, moths, flies etc.)
Hearing has evolved in some moths as a direct defence against predation by bats and moth ears tuned to frequencies emitted by bats known to prey upon them
Name the three types of crypsis
Background matching- Catocala moths
Countershading- Birds, trout, penguins, dark on upper side and light on bottom
Disruptive colouration- break up the outline of an animal, nightjar.
Give 2 examples of preventing recognition
Prey polymorphism- Grouse locust, many different forms
Masquerade- look like something inedible (Early thorn moth looks like twig/thorn).
Define aposematism
Warning coloration to warn predators of the unprofitability of the prey
Explain how aposematic signals exploit aspects of predator psychology
- Wariness of certain patterns/colours
- Capacity to learn
- Memory retention of learnt avoidance
- Recognition processes
Chick receiver psychology
Top graph: chicks trained to obtain food from low contrast stimulus show initial high preference for HIGH CONTRAST novel stimulus. But quickly learn about unrewarded state, and remember this in subsequent tests.
Could this be because the birds are attracted to novel things?
Bottom graphs: chicks trained to obtain food from high contrast stimulus show NO enhanced interest in low contrast novel stimulus.
So HIGH CONTRAST SIGNALS ARE BOTH MORE QUICKLY LEARNT AND MORE MEMORABLE
Define Mullerian mimicry
2 distasteful species come to mimic each others warning signals. (helicons butterflies)
Define Batesian mimicry
Harmless species evolved to have the warning signals of a harmful species. (King snake (harmless) coral snake (harmful).
Definie Deimatic display
Sudden threatening or startling behaviour- flashing eyespots in moths. Often camouflaged until attack.
Define startle mimicry
e.g. Eyespots to startle predator
Give an example of a predator response to an escape behaviour
Tentacled snake exploits c-start behaviour in fish to catch them.
Give an example of an allocation cost
Freshwater snail expels blood with retreat from predator, then replaces fluids but often takes on parasites.
Give an example of an opportunity cost
Crypsis of moths/insects on oak trees= reduced habitat choice.
