L10 + L11 - Predator Prey Interactions Flashcards
In taxonomic classification of predators, what are the 3 kinds?
Carnivore, Omnivores, Herbivores
In functional classification of predators, what are the 4 types?
True predators, grazers, parasites, parasitoids
Describe how a grazer feeds
Grazers attack many prey, only taking part of each, attacks are usually not lethal
E.g.: herbivores such as sheep or cattle, flies that bite
Give 3 examples of parasites
Tapeworm, TB bacterium, measles virus
Describe how a parasitoid attacks it prey
A parasitoid attacks 1 prey and its attack is always lethal
Usually Diptera (flies) or Hymenoptera (wasps)
Account for 25% of the world’s species
When can herbivores have a serious effect on plants?
Germination or seed setting time
How do plants compensate for herbivores by shading?
The top leaves shade lower leaves, if eaten by a herbivore this lets light through to other leaves below and may even increase photosynthesis levels.
What 2 things can herbivores do that has a disproportionately harmful effect on the plant?
Ring barking, transfer of plant diseases, e.g.: Dutch elm disease and beetles
Give an example of how plant interactions are effected by the abiotic environment
Plants stressed by pollutants provide a better food source for herbivores as they have a high nitrogen content
What defensive methods do plants employ against herbivores?
After a herbivore attacks a plant increases the production of defensive structures or chemicals. Such as have delayed leaf production, tougher leaves, higher fibre and resin content, lower nitrogen content
Why are the effects on a population targeted by predators not predictable?
The survivors might compensate for the loses - reduced intraspecific competition
targets aren’t random they are usually on the weak, ill or young, which generally haven’t yet or aren’t giving much to the population as a whole - least likely to survive or reproduce
How does an unlimited supply of food effect a natural enemies growth?
They continue to grow as a population until the limit is reached as they cant only eat so much and grow so much
Define Monophagous, Oligophagous and Polyphagous
Monophagous - is a specialist and only eats one kind of food
Oligophagous - eats a few different food
Polyphagous - is a generalist and eats many kinds of food
Describe the functional response of a Type 1 natural enemy
Type 1 consumption rate rises linearly as prey density increases. At a certain level consumption levels off and remains constant
Describe the functional response of a Type 2 natural enemy
Type 2 consumption rate rises non-linearly as prey density increases as it is easier to catch. At a certain level consumption levels off and remains constant`
