Flashcards in Mutualistic dependence seminar Deck (7)
virtually every species on earth is involved in one or more mutualisms; this type of relationship may represent ... of the interactions in communities
Mutualisms provide essential ecosystem services (e.g. ... is worth 30 billion a year to the US economy alone)
Assumptions of the tit for tat model:
- no ... differences between species
- The services exchanged cannot evolve
- The payoffs associated with cooperation, defection, cheating and being cheated are ...
- Partners need to ... previous interactions
These assumptions are not met in most mutualisms
ecological, constant, remember
Mutualistic ... varies a lot.
dependence (e.g. none, facultative, obligate)
Does mutualistic dependence affect mutualism breakdown at the geological scale?
Ant plants phylogeny - facultative generalist is intermediate ancestral state. There were 4 increases in dependence (obligate) and 12 losses of dependence (non-mutualists). The non-mutualist state NEVER evolved from the specialised obligate state, only the facultative
- the level of dependence of mutualism affects the likelihood of breakdown at an evolutionary scale
Does mutualistic dependence affect the efficiency of the service provided?
Small clade of ant plants - do obligate ant-plants get more nitrogen from ants than facultative ant-plant species?
The facultative type has limited nitrogen uptake capacity and no apparent selection on the location of defecation (pretty much even throughout plant). The obligate type has a very clear differentiation - the ants exclusively defecate in the warty (rather than the smooth) chambers and uptake here is significantly higher.
Removing the ants from both types and measuring the amount of nitrogen in the plants 16 months later showed that the obligate ant-plants get 2.5-fold more nitrogen from ants than facultative species - so yes, they are more efficient