Zusammenfassung der Ressource
Food Webs
- producers at the bottom up trophic levels to top predator
- Autotrophs (producers) make their own energy using sunlight
- Second trophic level = herbivores
- Secondary consumers consumer herbivores
- Apex predators (top of foodchain)
- 90% of energy is lost between trophic levels
- so foodchains are short with 4-6 links
- Exchange of energy up foodchain
- Complex
- more than one food chain in an ecosystem
- Organisms consume a wide variety of
food and have a range of predators
- Organisms may eat herbivores and small carnivores, their prey may be shared
with other species = overlapping food webs
- Basic = observations of who eats who
- Energy flow diagram
- shows significant links in terms of
the amount of energy exchanged
- Functional links
- only detected using experiments
- Breaking links and recording the effects
- A significant change in population numbers would
determine that the link is functionally important
- Eg. Starfish & Mussels. when starfish is removed the mussel
outcompetes other organisms, starfish keep numbers low
enough for other species to colonise the area