Ch. 14: Mutualism

Ecological engineers

-another example of commensalism -provide habitat for other organisms without themselves being affected -they are the "0" organisms

Ants & Acacia trees

-ants live in thorns along the branches of acacia trees -trees provide shelter to ants in their thorns -trees also provide food to the ants in the form of energy-rosh droplets (Beltian bodies) at the tips of their leaflets -ants defend the acacia tree by attacking animals that try to feed on the tree & plants that come into contact with the tree -Example of trophic, habitat, & service mutualism -Non-symbiotic b/c, even though ants live within the acacias, there is no physiological integration b/t them

Nitrogen-fixing bacteria in root nodules

-bacteria fix soil nitrogen (which plants can't do) and provide it to the plants -plants provide photosynthates and shelter to the bacteria -Example of trophic & habitat mutualism (symbiotic)

Cleaner & client fish

-cleaner fish (smaller species) feeds on parasites of client fish (larger species) frequently within the mouth -cleaner fish receives food -client fish receives defense from parasites -Example of trophic & service mutualism (non-symbiotic)

Bacteria and protozoans in animal guts

-common in mammals and insects -bacteria/protozoans break down cellulose and other indigestible substances for the animals -animals provide nutrients & shelter to the bacteria/protozoans -Example of trophic & habitat mutualism (symbiotic)

Pollination

-flowering plants provide food (nectar) to pollinating animals (insects, birds, bats) -animals disperse the plant gametes (pollen) from one plant to another, resulting in fertilization -Example of trophic & service mutualism (non-symbiotic)

Fruits

-flowering plants provide food to fruit-eating animals -animals disperse the seeds of the plants with their feces -Example of trophic & service mutualism (non-symbiotic)

Mycorrhizae

-fungi wrap around & extend within plant roots, plus spread out through the surrounding soil -fungi provide inorganic nutrients from the soil to the plants -plants provide photosynthates to the fungi -Example of trophic mutualism (symbiotic)

Leafcutter ant fungus gardens

-leafcutter ants maintain "gardens" of fungi within their colonies -ants cut & bring leaves to the fungi for decomposition, as well as "fertilize" the fungi with inorganic nutrients from their feces -fungi break down the cellulose in the leaves to a form that is edible for the ants -Example of trophic mutualism (non-symbiotic)

Decomposition

-most common & important type of commensalism (+,0) -Decomposers (detritivores) obtain nutrients from dead organisms (detritus), which are not positively or negatively affected -bacteria & fungi are the most common decomposers, though certain animals (beetles, millipedes, & vultures) are involved as well -decomposers are the "+" organisms in a "+,0" commensalistic relationship

Habitat mutualisms

-organisms receive a suitable habitat (shelter) from their mutualistic partners

Trophic mutualisms

-organisms receive food (nutrients & energy) from their mutualistic partners -Ex: mycorrhizae

Service mutualisms

-organisms receive vital services (such as dispersal or defense) from their mutualistic partners

Lichens

-unicellular green algae or cyanobacteria living within fungi -algae/bacteria provide photosynthates to the fungi -fungi provide inorganic nutrients & shelter to the algae/bacteria -Example of trophic & habitat mutualism (symbiotic)

Corals & zooxanthellae

-zooxanthellae (dinoflagellates) live within the tissues of corals (cnidarians) -zooxanthellae provide photosynthates to the corals, as well as stimulate the production of reef material -corals provide inorganic nutrients & shelter to the zooxanthellae -Example of trophic & habitat mutualism (symbiotic)