Over two decades ago in the People's Republic of China, it was noticed that songbirds were eating rice and millet drying on the grain floors. Since there were large numbers of people to feed, and the population was very near to carrying capacity, it was proposed that the songbird population should be reduced in order to preserve more grain. However, the songbirds also ate a larger number of insects that fed on the rice and millet when it was young. Draw a food web including the above items, indicating energy flow in the direction of the arrows, and representing the general proportion of energy consumed by the breadth of each arrow. State briefly why this decision was disastrous.

Question

What will be an ideal response?

Answer 1

In this scenario, rice and millet are consumed by people, insects, and songbirds. One might assume that the millions of people consumed more of the grain than the songbirds. However, the songbird problem was significant, since the people considered their removal. With the removal of songbirds, which are a major predator of the insects, there would be a huge increase in the number of insects. The insects would destroy the rice and millet plants when they are young. The disaster is that the insects may destroy the entire plant, resulting in absolutely no productivity from the plants. Songbirds, by feasting on the grain after harvest, share the wealth with the people … a redistribution of the wealth … one might say. So, even though the birds are decreasing the amount of food available to people, removing the songbirds from the ecosystem is not the answer to the problem.