EE Lecture 17: Intro to Ecology Flashcards
what is Liebigs Law of the Minimum
the only limiting factor is the most limiting factor
eg. the only limiting nutrient is the nutrient whose supply is furthest from the requirement
what is Mitscherlich’s LAw
yield depends on all the sub optimal factors, nut just the most deficient one
the smaller the interval between the actual value of a factor and its optimum, the smaller the effect of change in that factor
compensation can occur, as when temp is increased temp may partly compensate for low nutrient content by increasing weathering rate
in terms of Mitscherlichs Law, how can compensation occur
when increased temp, can partly compensate for low nutrient content by increasing weathering rate
what are the fundamental biotic interactions
competition
predation
mutualism
what kinds of competition are ther
scramble
contest
which type of comp is most destabilizing
scramble
`what is contest competition
winners and losers;winners get all or most of what they require, losers get little or nothing
what is scramble competition
all individuals get roughly same amount of resource
what are the main mechanisms of competition
exploitation - scramble
interference - contest
how does exploitation occur
through reduction of a shared resource
how does interference occur
behavioural - territoriality, mate choice
chemically - alleopathy
which type of competition normally involves interference
contest competition
which type of competition is symmetric - in what way
scramble comp is often symmetric - all individuals suffer more or less equally
give example of symmetric competition
scramble
eg. rabbits in grass - all individuals reduce supply
give example of asymmetric comp
light comp in plants
the tallest plant gets ALL light and shades smaller plant
CONTEST comp
how much % primary plant production do herbivores take
around 15%
how much animal production % do predators take
30%
discuss resource acquisition mutualisms in plants and nitrogen
nitrogen fixing Rhizobium in root nodules of legumes
substantial carb payment by plant to nodulestrade off means that plant will only pay for bac to fix N when N is limiting
prediction: Rhizobium fixation will decline when fertiliser N is applied
what are main types of mutualisms for
- resource acquisition: Rhizobium+legumes
2.Defence : ant acacia
3.Pollination: figs and fig wasp
4,Gut flora
what is exploitative comp
2 consumers share common prey and may compete indirectly
what is apparent comp
2 prey species may only appear to compete because if either increases, a shared predator also increases which affects other prey pop
what is competitive mutualism
pops of 3 species at same trophic level
what is indirect mutualism
pops C1 and C2 dont interact directly cos consume different prey but the prey compete
what is food chain mutualism
trophic cascade - 3 species at 3 different trophic levels
