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Should We All Be Vegetarians?
In class we have been talking about how the amount of energy transferred through the trophic levels in an ecosystem decreases at each higher level of the food chain. For example, if a 75-kg (165-lb) person ate frogs (and some people do!), he would need 10 a day, or 3,000 a year. If each frog ate 10 grasshoppers a day, the 3,000 frogs would require 9,000,000 grasshoppers a year to supply their energy needs. A horde of grasshoppers of that size would require 333,000 kg (732,600lb) of wheat to sustain them for a year.
If people fed on grasshoppers rather than frogs, each person could probably get by on 100 grasshoppers a day. The 9,000,000 grasshoppers could support 300 people for a year, rather than only one. If, instead of grasshoppers, people ate wheat, then 333,000 kg of wheat could support 666 people for a year.
This argument is often extended that to suggest that people should become herbivores (vegetarians) and eat directly from the lowest level of all food chains, the autotrophs. Consider, however, that humans can eat only parts of some plants. Herbivores can eat some parts of plants that humans cannot eat and some plants that humans cannot eat at all. When people eat these herbivores, more of the energy stored in plants becomes available for human consumption.
Discussion Questions
Resources:
http://www.time.com/time/covers/1101020715/story.html
http://www.emagazine.com/view/?142