Author: canon787

What do u think about these pitcures? [Copy link] 中文

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Post time 2008-4-21 22:10:47 |Display all floors
The food chain


What is the difference between the 'Food Chain' and 'Food Web?'

A popular misnomer, the 'food chain' is not actually a linear chain but a complex web.  Energy is passed from one organism to another in a complex network like a spider's web.

The food chain consists of four main parts:

1) The Sun, which provides the energy for everything on the planet.

2) Producers: these include all green plants.  These are also known as autotrophs, since they make their own food.  Producers are able to harness the energy of the sun to make food.  Ultimately, every (aerobic) organism is dependent on plants for oxygen (which is the waste product from photosynthesis) and food (which is produced in the form of glucose through photosynthesis).  They make up the bulk of the food chain or web.

3) Consumers: In short, consumers are every organism that eats something else.  They include herbivores (animals that eat plants), carnivores (animals that eat other animals), parasites (animals that live off of other organisms by harming it), and scavengers (animals that eat dead animal carcasses).  Primary consumers are the herbivores, and are the second largest biomass in an ecosystem.  The animals that eat the herbivores (carnivores) make up the third largest biomass, and are also known as secondary consumers.  This continues with tertiary consumers, etc.

4) Decomposers: These are mainly bacteria and fungi that convert dead matter into gases such as carbon and nitrogen to be released back into the air, soil, or water.  Fungi, and other organisms that break down dead organic matter are known as saprophytes.  Even though most of us hate those mushrooms or molds, they actually play a very important role.  Without decomposers, the earth would be covered in trash.  Decomposers are necessary since they recycle the nutrients to be used again by producers.



Source:http://library.thinkquest.org/11353/food.htm

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Post time 2008-4-22 12:41:40 |Display all floors
thankyou for that interesting show on biology, brought to us by the thunderbird wildlife channel

when is the next episode? I want to see more food getting eaten by more food that i want to eat

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Post time 2008-4-22 19:26:49 |Display all floors
I think it must be in  north Europe ,such as sweden   finland  norway !!!
untill watched these images have i understand a chinese idiom  called "xue   liu  cheng  he "!!!
in the summer vocation last year ,i have watched documentary  on CCTV  which commemorates the victims in World War 2 ,the Nanking Massacre ,it told how our compatriots had been killed and thrown to the changjiang   river , accroding to what the vedio said :there were  thousands of cadavers floating above the water so that them can wall up the Changjiang River .
so ,i thought , in the 1937,our land had happened the same situation

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Post time 2008-4-22 19:28:58 |Display all floors
I think it must be in  north Europe ,such as sweden   finland  norway !!!
untill watched these images have i understand a chinese idiom  called "xue   liu  cheng  he "!!!
in the summer vocation last year ,i have watched documentary  on CCTV  which commemorates the victims in World War 2 ,the Nanking Massacre ,it told how our compatriots had been killed and thrown to the changjiang   river , accroding to what the vedio said :there were  thousands of cadavers floating above the water so that them can wall up the Changjiang River .
so ,i thought , in the 1937,our land had happened the same situation

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Post time 2008-4-22 21:36:02 |Display all floors

OH~~~My

why  are these people killing them?so many !!!!!

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Post time 2008-4-23 06:55:39 |Display all floors
Originally posted by justbabygirl at 2008-4-22 12:41
thankyou for that interesting show on biology, brought to us by the thunderbird wildlife channel

when is the next episode? I want to see more food getting eaten by more food that i want to eat


Next episode is called the fishy trilogy!   

Big fish eat small fish....small fish eat tiny fish...tiny fish eat....and you know who eats big fish!   



Source:http://www.fao.org/newsroom/en/news/2006/1000383/index.html

Nearly half of all fish eaten today farmed, not caught:


Aquaculture only way to meet surging demand, but challenges to future growth loom
4 September 2006, Rome/New Delhi - Nearly half the fish consumed as food worldwide are raised on fish farms rather than caught in the wild, says a new report from FAO.

"The State of World Aquaculture 2006" was presented today to delegates from more than 50 countries attending the biennial meeting of the FAO Sub-Committee on Aquaculture (New Delhi, 4-8 September*).

While in 1980 just 9 percent of the fish consumed by human beings came from aquaculture, today 43 percent does, the report shows.

That's 45.5 million tonnes of farmed fish, worth US$63 billion, eaten each year. (Currently, freshwater and marine capture fisheries produce 95 million tonnes annually, of which 60 million tonnes is destined for human consumption).

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Post time 2008-4-23 06:58:44 |Display all floors
Source:http://www.time.com/time/health/article/0,8599,1663604,00.html

Close to 40% of the seafood we eat nowadays comes from aquaculture; the $78 billion industry has grown 9% a year since 1975, making it the fastest-growing food group, and global demand has doubled since that time. Here's the catch: It takes a lot of input, in the form of other, lesser fish — also known as "reduction" or "trash" fish — to produce the kind of fish we prefer to eat directly. To create 1 kg (2.2 lbs.) of high-protein fishmeal, which is fed to farmed fish (along with fish oil, which also comes from other fish), it takes 4.5 kg (10 lbs.) of smaller pelagic, or open-ocean, fish. "Aquaculture's current heavy reliance on wild fish for feed carries substantial ecological risks," says Roz Naylor, a leading scholar on the subject at Stanford University's Center for Environmental Science and Policy. Unless the industry finds alternatives to using pelagic fish to sustain fish farms, says Naylor, the aquaculture industry could end up depleting an essential food source for many other species in the marine food chain.

A farmed salmon.jpg

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