predation Flashcards
(17 cards)
community ecology
a group of potentially interacting species living in the same location
species interactions
- competition
- predation
- herbivory
- parasitism
- mutualisms
food webs interactions
interaction between two species in one part of the web can affect species some distance away, due to complex inter connections
direct effects
impacts of species A on species B in a two species interaction
indirect effects
impact of species A on species C via intermediary species ( A > B > C )
what is a predator?
any organism that consumes all or part of another living organisms
benefits itself by reducing growth, fecundity or survival of the prey
what are ‘true’ predators?
kill prey immediately after attacking them, consume several or many prey items in course of life
what are grazers?
attack several or many prey items in life, consume only part of each prey item. dont usually kill their prey
what are parasites?
consume only part of each prey item (the host), don’t usually kill their prey, make prey more vulnerable to mortality
why is predation important?
- affect abundance and distribution of prey populations
- affect competition
- selective force, causes adaptations from predation pressure
what are some decisions when foraging?
- choosing between habitats
- conflict between increasing input and avoiding predators
- conflict between patch quality and competitor density
- optimal diets
what is compensatory change?
when the removal of one species in an ecosystem is followed by the growth or increase in abundance of other species.
what is the Lotka-Volterra model?
useful tool to help population ecologists understand the factors that influence population dynamics, to predict predator-prey population dynamics.
What regulates populations?
Top down control = predation e.g parasites and disease
Bottom up control = resources e.g food, nest sites
examples of prey defence?
- Avoiding detection: camouflage, aposematism, mimickry
- Vigilance & safety in numbers
- Predator satiation
- Fighting back: chemical & structural defenses
- Look out sentries/guards
what is vigilance?
prey seek to forage as much as possible while avoiding being captured by predator if none of the group are vigilant the target prey captured 100% of the time.
what is chemical defence?
the use of poisonous chemicals for defence, often bitter tasting
e.g Bombardier beetle, specialized glands on the tip of its abdomen that allows it to direct a toxic spray towards predators
