Food Chain - show the flow of matter & energy
linked together the relationship between producers and consumers:
producer --> primary consumers --> secondary consumers --> tertiary consumers ---> ...
- can only show one organism at each trophic level
- can't be sure if the organism is omnivore or feeding at 2 or more trophic levels
Food Web
Allow us a better understanding of the ecosystem, which, in this case of interaction, is feeding.
Food web is a combination of different food chains, showing different trophic leves:
- multiple preys
- multiple predators
- linked
eg) An organism can be secondary or tertiary consumer at the same time.
Pyramids --> quantifying the food chain
1. Pyramid of Number - shows the number of organism at each trophic level (eg. counting)
-1 hawk-
---10flycatcher---
---------100 carrotflies----------
------------1000 carrot plants--------------
problem: limitation in expression of energy
-1 hawk-
-----100 birds-----
----------------1000 bees--------------
-1 plant-
(notice the tiny base... energy cannot be represented this way)
2.Pyramid of Biomass - shows the mass (of matter) contains at each trophic level
Because water content varies and took up a large percentage, we only calculate the amount of dry mass in biomass.
*measured in kg/area
3. Pyramid of Energy - shows the flow of energy, therefore it cannot be inverted
-1% consumer-
-----10% producers--- *unit = energy = J/ kJ
------------------100% sunlight------------------ = area = m2
= time = m/s/yr
(notice the decreasing amount of energy at 10% per trophic level)
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