Chapter 6 - Interspecific Competition (SLIDES) Flashcards
How do grazing and infection impact organisms?
They decrease competitive abilities, increase susceptibility to predation, and trigger compensatory and defensive responses.
What are some plant responses to grazing?
Compensatory responses (e.g., shedding leaves) and defensive responses (e.g., structures, chemicals).
How can predation relieve competitive pressures?
By reducing competition when food is scarce, allowing individuals to survive that otherwise wouldn’t.
How does foraging behavior affect predation?
It determines contact patterns between predators and prey, affecting consumption rates.
How do true predators and grazers forage?
They actively move within habitats to find prey.
How do web-spinning spiders or sessile organisms establish contact with prey?
They rely on prey coming to them or settling in suitable locations.
How do parasites and pathogens differ in their foraging strategy?
They rely on transmission rather than active searching.
What factors influence direct parasite transmission?
The density of both susceptible and infected hosts.
What does optimal foraging theory explain?
It describes why certain foraging behaviors have evolved based on maximizing energy intake.
When should a predator leave a foraging patch?
When they gain more by moving to a new patch.
How does competition affect predator distribution?
Predators distribute themselves in proportion to resource availability (ideal free distribution).
What determines a predator’s diet width?
The balance between energy intake and handling time.
What type of predators should be generalists?
Those with short handling times relative to search times.
What type of predators should be specialists?
Those with long handling times, focusing on the most profitable prey.
Why do predator and prey populations exhibit oscillations?
Due to time delays in their responses to each other’s population size.
What is the Lotka-Volterra model?
A mathematical model describing predator-prey cycles.
How does crowding affect predator-prey cycles?
It dampens cycles by increasing mutual interference and limiting population growth.
What is the Basic Reproductive Number (R0) of a parasite?
The average number of new infections caused by one infected host.
What happens if R0 > 1?
The disease spreads.
What happens if R0 < 1?
The disease fails to spread.
What are metapopulations?
Populations divided into subpopulations linked by dispersal.
How does predation influence species coexistence?
It can promote coexistence by keeping dominant competitors in check.
Why is species richness highest at intermediate predation levels?
Because predation prevents dominance by a single species while still allowing diversity.
What is interspecific competition?
Competition for resources between different species.
Give an example of interspecific competition.
The grey squirrel outcompeting the native red squirrel in Europe.
How can you test whether two species are competing?
Remove one species and observe changes in the other’s population.
What is the Competitive Exclusion Principle?
If two species compete for the same niche, one will exclude the other unless niche differentiation occurs.
What is niche differentiation?
Differences in resource use that allow species to coexist.
Give an example of niche differentiation.
Different whale species feeding at different depths.
How do mussels exhibit niche differentiation?
The Mediterranean mussel has a higher temperature range than the blue mussel.
What is character displacement?
Evolutionary changes in species due to past competition, reducing direct competition.
How do Darwin’s finches show character displacement?
When living together, their beak sizes differ more than when living separately.
What is niche complementarity?
When coexisting species share one niche dimension but differ in another.
Why might interspecific competition be overestimated in studies?
Studies often focus on species expected to compete, leading to bias.
What is resource partitioning?
Species using different resources to reduce competition.
