Coevolution & Symbiosis Flashcards
Coevolution
two or more unrelated species adapting to each other
Pairwise coevolution
involving just two particular species (hence, pair).
Ex: a particular plant and particular pollinator
Diffuse coevolution
involving multiple species (many species of bugs pollinating many plants)
Symbiosis
examples of commensalism, mutualism, parasitism characteristics of parasites (parasite/guest benefits from all of these)
Commensalism
host is not affected (shark and remora)
Mutualism
host benefits from symbiosis (clownfish and anemone)
Parasitism
symbiosis harms the host (crabs, tapeworms, etc)
Brood parasites
birds lay their eggs in the nests of other birds and make no contribution to parental care. Some parasite species mimic the young of the host species to “fit in” more
Species-specific
some birds only target one host species (this is more benign for the host species!)
Generalist parasites
targets and parasitizes many host species
Parasites adaptations
- eggs have thick shells
- eggs develop faster
- young grow faster and more demanding
- destroy host eggs
- destroys host nest if egg is recognized (mafia strategy)
Host counter-adaptations
- Drive away parasites
- Eject or bury eggs
- Abandon nest
Photosymbiosis
dinoflagellates = zooxanthellae
- Mutualism
- Necessary for massive coral reefs
- Also maintains the pH of the water; provides more oxygen and carbohydrates
Hermatypic corals
- Must have zooxanthellae to survive (obligative, mutualistic symbiosis)
- Zooxanthellae remove CO2 and provides oxygen, which is necessary for the coral
Coral bleaching
- When temperatures get too high for the zooxanthellae
- Once zooxanthellae pigmentation leave, the corals’ white calcium carbonate skeletons are exposed
- Usually results in the death of the coral host
