Ecology - Chapter 15

What is mutualism?

interactions between individuals of diff species that benefit both

What is facultative mutualism?

when species can live w/o mutualistic partner

What is obligate mutualism?

when species is dependent on mutualistic relationship

How have eukaryotes originated as?

mutualistic associations

What do plants have mutualistic partnerships with?

fungi and animals

What role do plants have in mutualistic relationships that affect structure and processes of terrestrial organisms?

center

Why are plants in the center of mutualistic relationships?

N fixation, nutrient absorption, pollination, and seed dispersal

What do mycorrhizal fungi provide plants with?

greater access to inorganic nutrients

What are arbuscular mycorrhizal fungi?

fungus produces arbuscules (exchange sites), hyphae (fungal filaments), and vesicles (E storage organs)

What are ectomycorrhizae?

fungus forms mantle around roots and net-like structures around root cells

What do plants w/ mycorrhizae maintained?

higher leaf water potentials

What do mycorrhizal fungi provide more extensive contact with?

moisture in rooting zone, providing more surface area for water absorption

What does the fungal partner receives?

= or greater quantity of photosynthetic products in trade for lower nutrient quality

What do plants release more of in nutrient poor environments?

carbohydrates in root exudates

How does higher shoot mass occur?

with mycorrhizae and nutrient supplements

How does higher root:shoot rations occur?

low N conditions

What do reef-building corals depend on?

mutualistic relationship with algae and animals

What does the ecological intergrity of coral reefs depend on?

mutualism

Where will mutualism evolve?

where benefits of mutalism exceed costs

What are Successful mutalists?

give and receive benefits

What are Unsuccessful mutualists?

give, but don’t’ receive benefits

What are non-mutualists?

neither give or receive benefits

What must occur for a pop to be mutualistic?

fitness of successful mutualists must be greater than unsuccessful or nonmutualists

What does the combined fitness of successful and unsuccessful mutualists must exceed?

that of nonmutualists

What will happen if nonmutualists’ fitness is not exceeded?

natural selction will eventually eliminate interaction