Predator-prey relationships Flashcards
1
Q
What is predation? What effect does it have on population size?
A
- major biotic fator that affects population size
- where an organisms kill another organism (the prey)
2
Q
How is their competition between predators and prey?
A
- predators evolve to beocme highly effiecient at capturing prey
- e.g. speed, stealth, reaction
- prey organisms have evolved to avoid capture
- e.g. camoflauge or defence mechanisms such as spines
3
Q
How are population of predator and prey interlinked?
A
- as population of one organism changes, it causes a change in the size of the other population
- this causes fluctuation in populations
4
Q
predator-prey relationships follow the same pattern
describe the graph
A
- peals and troughs in the size of prey population are mirrored by the peaks and troughs in the size of predator population after a time delay
5
Q
What does each stage show?
A
- stage one
- increase in prey population provides more food for predators
- thus allowing more to survive and reproduce
- this causes and increase in the predator population
- stage two
- increased predator population eats more prey organisms, causing a decline in prey population
- death rate of the prey population is greater than its birth rate
- stage three
- the reduced prey population can no longer support the large predator population
- intraspecific competition for food increases, resulting in a decrease in the size of the predator population
- stage four
- reduced predator numbers result in less of the prey population being killed
- more prey organisms survive and reproduce, increasing the prey population - the cycle begins agains
6
Q
Why is the link rarely as simple as this in wild ?
A
- other factors influence population size
- e.g. availability of food plants of the prey
- or presence of other predators
- fluctuations in numbers may also result from seasonal changes in abiotic factors
