Ecology: Mutualism

Mutualism

an interaction that has net positive effects on both of the interacting species

generalist vs specialist

diversity of partners

generalist

can benefit from many different species

how are bees an example of generalist?

bees pollinate many different types of flowers

specialist

depends on one or few species

obligate vs. facilitative

the degree of dependence on mutualist for fitness

obligate

need each other to survive

facultative

benefit from each other but can survive independently

how is the relationship between birds and mammals facultative?

birds eat insects off large mammals but both can survive without relationship

what are the 4 types of mutualism?

1) nutritional exchange

2) protection

3) transportation

4) cooperation by-product

Protection mutualism

nutritional exchange mutualism

one species gives a resource to the other species which provides protection from natural enemies

trade essential nutrients to each other cus neither can produce those nutrients on their own

how do sea anemone and clownfish display protection mutualism?

sea anemone has stinging tentacles that keep predators away and clownfish have a protective mucus coating that prevents them from being stung so the clownfish hides in the anemone and chases away animals that eat anemone

how does ant acacia display protection mutualism?

acacia tree has hollow thorns where ants live and build nests and ants attack animals that try to eat the trees leaves and other competing plants

transportation mutualism

one species gives a resource to the other species which provides transportation in return

what kind of mutualism is common in species that are immobile for large portions of their life, such as plants?

transportation mutualism

pollination of flowers and animals disposing of seed after eating a plants fruit are examples of what?

transportation mutualism

cooperation by-product mutualism

species cooperate with benefits to each arising as a byproduct of their interaction

Explain how cooperative defense is an example of cooperation by-product

two species work together to defend themselves against predators

Explain how cooperative hunting is an example of cooperation by-product

two species hunt together making it easier to catch food

how do humans engage in mutualisms?

gut microbes outcompete pathogens and break down complex carbs into nutrients we can absorb while we provide them nutrients and a stable environment

how do humans and honeyguide birds display mutualism?

humans help them access beeswax from hives and the birds lead humans to beehives so they can collect honey

how do humans and agroecology display mutualism?

farmers plant different crops together so different pollinators are attracted and plants provide habitat for insects that control crop pests

cheaters

organisms that were once mutualistic partners but begin taking benefits at the other species expense

how is the cleaner fish an example of a cheater?

cleaner fish normally eat parasites off larger fish but when parasites are scarce cleaner fish start eating the larger fish’s mucus and scales

what are 2 ways to deal with cheaters?

1) reward and punishment

2) partner manipulation

what is the reward in reward and punishment with cheaters?

partners can incentivize mutualism by favoring the most beneficial partner

what is the punishment in reward and punishment with cheaters?

partners can punish cheaters by denying them a resource

how does the relationship between plants and fungi display reward?

plants give more carbon to fungi that provide them with more nutrients

how does the relationship between a yucca moth and yucca plants display punishment?

moths lay their eggs inside the developing fruit where their larvae eat some of the developing seeds but if moths lay too many eggs the yucca plant can abort the fruit killing the larvae inside

partner manipulation

partners make it so that the other is dependent on their interaction

how does the relationship between ants and acacias display partner manipulation?

acacias produce enzymes in their extrafloral nectar that cause ants to lose their ability to digest other types of nectar

how does mutualisms help specie survive in new places?

provides resources and protection that allow species to survive in places they otherwise couldn’t

How can mutualisms promote invasions? Use the honeybees as an example.

honeybees introduced to north america can establish populations and interact with native plants via pollination

How can breaking mutualisms cause local extinction? Use coral bleaching as an example.

in coral bleaching corals lose their symbiotic algae which provides their energy so reefs can die off

how does mutualism promote species diversity?

mutualists help other species survive and reproduce allowing more species to coexist

how does mutualism promote fitness?

species that interact with mutualists have better survival

how does mutualism influence a mobile specie’s habitat choice?

may choose to live in areas where beneficial mutualists are

In an experiment, researchers increased the number of mycorrhizal fungal species in a grassland. More fungal diversity led to greater phosphorous accumulation and greater plant biomass. Why? What does this prove?

Different fungal species can help plants access nutrients in different ways increasing the amount of phosphorous available to plants. Greater mutualist diversity can improve nutrient cycling in ecosystem productivity.