Populations - Predation and Herbivory Flashcards
Describe predator-prey dynamics
Predator-prey dynamics simultaneously oscillate to produce cyclical patterns. As prey increases, so will predators. Then prey will decrease in response to higher predation. This causes predator numbers to decrease because there is less food. Prey numbers increase in response to the lessening of predator pressure… and the cycle repeats.
Predict the outcomes of predator-prey interactions
Predators can respond to prey density fluctuations according to numerical, functional, aggregative, and developmental models
Link concepts between physical environment, populations & competition
The physical environment does not provide limitless resources - they must be competed for. The competition influences populations because successful individuals will pass their characteristics onto the next individuals. These individuals make up the population.
How do the complex interactions between predators and prey impact population growth dynamics?
Both predators and prey are impacted by their own abundance and each other’s abundance
Predation
One species of animal killing and consuming another species (interspecific)
Herbivory
Animals eating plant tissues
How do predators and herbivores limit population growth?
High prey populations can increase predator reproductive rate
Low predators can increase prey reproductive rate
How do predators respond to prey abundance/density (4)?
Numerical, functional, aggregative, developmental
Predator response to prey increase: numerical
Prey continues to increase at the rate of consumption
Predator response to prey increase: functional
Consumption increases with increasing prey density
Predator response to prey increase: aggregative
Predators move to areas of high prey abundance
Predator response to prey increase: developmental
Consumption of prey varies with age
Population growth of prey is a function of…
Initial prey abundance and predator abundance
Population growth of predators is a function of…
Initial predator abundance and prey abundance
Prey equilibrium
Number of predators needed to stabilize prey population
Predator equilibrium
Number of prey needed to stabilize predator population
Review cyclical predator and prey models - they are simultaneous
What are the three types of predator functional responses to prey abundance?
Type I: consumption of prey remains constant despite changes in prey density (linear)
Type II: consumption of prey is increased by lower search times, but limited by handling time (asymptotic)
Type III: predators will switch to more abundant prey at a certain density, but consumption of prey is limited by handling time
How have prey responded to predation?
Evolve defenses:
Behavioural, crypsis, structural, chemical
How do plants defend themselves against herbivory?
Adaptations in structure, chemicals, and tolerance
