Predation Flashcards
Define predation
When 1 species serves as a resource for another
- clear asymmetric benefits
What are the 4 types of predatory relationships?
Predators sensu latu
Herbivores
Parasites
Parasitoids
How do predators affect prey populations?
Normally consume the whole prey
–> removes a member of the population
How do predators differ morphologically from their prey generally?
Larger
- except in cooperatively hunting animals e.g. wild dogs
What are the features of parasites?
> Consume parts of living prey
Attach themselves to host & fully depend on them
Do NOT kill host
What are the features parasitoids?
> Wasps & flies whose larvae consume tissues of living host
Large kill host
What to prey & predator population sizes tend to do?
Cycle
What is capture efficiency?
The rate of prey capture by a predator
Why doesn’t predation lead to extinction in nether prey nor predator populations?
Predators switch to alternative preys
- -> diversify food source quickly to prevent their extinction
- -> original prey no.s can increase again
What was the experiment used to test whether predators or carrying capacities regulate prey populations?
Exclude waders from some areas of beach using exclosure
–> compare prey densities between excluded & control sites
What were the results of the Wader experiment?
Inside exclosure = prey densities increases
Outside = prey densities decreased
Suggests prey population being controlled by predators
An increase in food to an environment increases which population?
What does this indicate?
Predator
Prey population size is controlled by predators
How did the introduction of parathion pesticide affect the cyclamen strawberry mite?
Reduced predatory mite populations
–> allowed prey Cyclamen population to grow rapidly to v high levels
Natural selection should favour predator strategies that…?
Increase resources
- -> associated w/ larger size & reproductive output
- -> favour genotypes with increased predatorily qualities
Can predator-prey relationships shape a species’ traits?
Yes
e.g. Tiger snakes on an island feed on gull chicks –> strong selection for larger jaws
