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What is an individual's fitness?
How successful a genotype is at passing on its genes to the next generation.
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What is the expected initial outcome of predation?
The abundance of prey will decrease. The abundance of the predator will increase.
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What is a food web?
All the interactions between the species in a community made up of many connected food chains.
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Predation is rarely observed in some species. What signs can indicate predation has taken place?
Drag marks, paw prints, remains
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Define predation.
The consumption of an organism by another where the prey is still alive when the predator attacks.
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What is the difference between true predators and grazers?
True predators kill prey immediately after attacking and may kill several-many prey in their lifetime. Grazers remove only parts of a prey individual which is rarely lethal. They will however attack large numbers of prey over their lifetime.
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Define: parasite.
an organism which lives in or on another organism (its host) and benefits by deriving nutrients at the other's expense.
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What are parasitoids?
Insects that lay eggs either in or on other individuals. In the larval phase the larvae devour the host which fuels them in their pupal stages.
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What type of behaviour is consuming only one other species?
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What behaviours do generalist predators display?
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What are oligophagous individuals?
Predators that feed on a restricted range of food substances
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What trends in populations are usually caused by predators showing specialist behaviour? Example?
Unstable predator-prey cycles - E.g. Boom and bust of Canada Lynx and snowshoe hare every 10 years.
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What is the trade-off between being a specialist or generalist predator?
Specialist predators= better adapted to exploiting one prey source- likely to be more successful but rely wholly on that food source. Generalists may have more unsuccessful attempts but have more food sources to turn to if one fails.
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Is predation random?
Not usually- cost benefit analysis. Predator will usually choose prey based on factors eg. time spent searching, handling, how much energy is obtained.
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Why are predators and prey likely to have coevolved?
Selection pressure for prey to become more successful at avoiding attacks/surviving attacks by predators. Predators will become more effective at exploiting their prey. Evolutionary arms race.
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Explain the method and results of the study carried out by Murdoch and Oaten 1975
Snails were offered different ratios of 2 types of prey. Even when prey species A was in low abundance, the snails preferred this species over B. Predator preference was maintained over a range of prey densities.
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Explain the findings of Davies 1977 studies on Pied wagtails and flies.
Pied wagtails preferred a size of fly which had the best compromise of high energy to handling time. This was the most profitable prey class.
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What is predator switching? Give an example.
This is where a predator concentrates on the most commonly abundant prey and will stop feeding one species when it becomes too rare. Lawton et al 19874- Water bug (Notecta glauca)
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How can prey avoid being eaten?
Morphology e.g. hard shell, spikes, toxins; Behaviour e.g. Fight/flee, living in groups
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What is crypsis?
A way to avoid detection or observation by another animals. It can be either a predation or anti-predation strategy and can include methods such as camouflage, nocturnality and mimicry.
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What is a specific searching image?
Related to apostatic selection of prey by predators- they look for specific clues which lead them to one prey species. Adopting this behaviour may cause them to become worse at spotting other prey species.
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Give some examples of generalist predators
Red foxes- prefer voles but will hunt other prey too. Brown bears- will hunt according to availability and may add to their diet with vegetative materials.
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Why was the introduction of the brown tree snake in Guam so destructive?
It is a generalist predator and a very successful invasive species. In places there were 6,000 snakes per m2. They wiped out the bird populations (which had no defences) and then switched to anything else they could find.
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Card 2


What is the expected initial outcome of predation?


The abundance of prey will decrease. The abundance of the predator will increase.

Card 3


What is a food web?


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Card 4


Predation is rarely observed in some species. What signs can indicate predation has taken place?


Preview of the front of card 4

Card 5


Define predation.


Preview of the front of card 5
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