Chapter 7 - Predation, grazing, and disease (CHAPTER) Flashcards
slides notes are NOT included!!
Predator
any organism that consumes all or part of another living organism (its prey or host) thereby, benefiting itself, but reducing the growth, fecundity, or survival of the prey.
True predators
invariably kill their prey and do so more or less immediately after attacking them
Consume several or many prey items in the course of their lives
Grazers
Attack several or many prey items in the course of their life
Consume only part of each prey item
Do not usually kill their prey, especially in the short term
Parasites
Consume only part of each prey item, usually called their host.
Do not usually kill their prey, especially in the short term.
Attack one or very few prey items in the course of their life, with which they therefore often form a relatively intimate association.
Parasitoids
Flies and wasps whose larvae consume their insect larva host from within, laid their ass eggs by their mother.
Ultimately kill their prey, so between parasites and true predators.
Attack one pray item in the course of their lives
Close association.
How do predators impact the fecundity and survival of their prey?
Predators reduce the fecundity and survival of individual prey.
How do grazers and parasites affect their hosts even if they don’t kill them immediately?
They make the prey more vulnerable to other forms of mortality and decrease their competitive abilities.
How do plants respond to predation
By producing more defensive chemicals or structures.
How can predation relieve competitive pressures among prey?
By reducing the number of individuals competing for limited food, allowing some that would have died to survive.
Why do predators sometimes have a limited impact on prey populations?
Because they often target old, young, or weak individuals, leaving fertile individuals to reproduce. What type of prey do predators typically attack?
What type of prey do predators typically attack?
The weakest and most vulnerable individuals.
How can predators indirectly reduce prey abundance?
By causing food shortages for other predators.
How can grazing and infection impact an organism even if they don’t kill it?
They can drastically decrease the organism’s competitive abilities and make it more susceptible to predation.
How do plants respond to grazing?
They can have compensatory responses like shedding leaves or defensive responses such as developing defensive structures and chemicals.
How do some surviving prey compensate after predation?
They may have compensatory reactions that help them survive despite environmental pressures.
How can predation sometimes relieve competitive pressures?
When food is scarce and competition is intense, predation can reduce the number of competitors, allowing some individuals to survive that normally wouldn’t.
What types of individuals do predators usually target?
: The weakest and most vulnerable individuals.
Do predators usually wipe out prey populations?
No, predators often do not wipe out prey populations, as compensatory effects help maintain population stability.
How do predators influence prey abundance?
They can reduce prey abundance, but compensatory effects prevent complete population collapse or significant decline.
Why is the pattern of contact between predators and prey important?
It determines the predator’s consumption rate and its impact on prey populations.
How do true predators and grazers typically find prey?
They forage by moving within their habitat to locate prey.
What determines the contact pattern between predators and prey?
The predator’s foraging behavior and, sometimes, the prey’s evasive behavior.
How do web-spinning spiders and sessile organisms establish contact with prey?
They rely on prey coming to them or settling in suitable locations.
Why is transmission more relevant than foraging for parasites and pathogens?
They spread through direct transmission between infected and uninfected hosts or through free-living stages of the parasite.
