Plants – thorns, tough leaves, spines, toxic chemicals, chemicals that attract predators/parasitoids (tobacco and wasps killing caterpillars). Removal of plant tissues stimulates growth.
Counter-adaptations – when prey and plants evolve to exert selection pressure back on predators and herbivores to evolve.
Visual/chemical camouflage to sneak up on prey Tolerance or detoxification of chemical defenses (honey badger)
types of mutualsim
Facultative mutualism – each species
can live w/o one another (ants and honeydew aphids)
Obligate mutualism – neither species
can exist without each other. (leafcutter ants and fungus)
autotroph, primary producers measured in C or biomass
Net primary production: gross primary production – respiration
Factors affecting npp
(heterotroph) – orgs that obtain energy by
eating other organisms’ remains
Detritivores – eat dead organic matter
1st (primary producers, autotroph),
2nd (primary consumers, herbivores),
3rd (secondary consumers primary carnivore),
4th (tertiary consumers, secondary carnivores)
Why pyramid shaped in terrestrial envs?
Proportion of biomass at each trophic level not consumed
Proportion of energy is lost in transfer
Control of NPP
resources that limlit NPP determine energy flow through an ecosys. Aquatic sys are limited by nutrients.
Silliman and Bertness(2002) manipulated snail density & found that grazing snails limit production of cordgrass. Removing the top predators (crabs ect) causes growth in snail pop, and decline in plant pop.
Ex of Trophic cascade – changes in abundance or species composition at one trophic level cause series of changes at other trophic level.
energy flow is governed by rates of consumption at highest trophic levels