Changing the Ecosystem

A food chain is a link between plants and animals. It starts with a plant. The next part of the link is a plant eater. When the prairie plants were uprooted, the animals that depended on them lost their food source. So while the farmers produced more food for people, they broke the animals’ food chain.

A food chain is part of a bigger system called a food web. That web links the living things in an ecosystem. The herbivores in that system depend on the plants. If the plants are removed, the herbivores cannot survive. Then the carnivores, the animals that eat other animals, lose their food, too. Remove just one kind of plant from an environment and you disrupt the food web. Plow up the land and you destroy the whole system. 

Read the following time-line and figure out the rate of population growth. To do that, divide the bigger number by the smaller number. You can estimate the answer. For example, one million is two times 500 thousand. For between 1880 and 1890 the population more than doubled. 

1880      Population of the city is 503,185; farms continue to expand
1890      Population of the city is 1,099,850
1900      Population is 1,698,676
1910      Factories expand in the city; population is 2,185,283
1920      City population has grown to 2,701,705
1929      A farmer near Chicago reports plowing up several frogs as he 
            got his field ready for planting this spring.
1930      City population is 3,376,438

We do not have population information on the butterflies, but we do know about the bison. By 1880, only a few hundred bison still live in this country. By 1900, Illinois and other Midwestern states were becoming known as the nation’s breadbasket. Millions of acres of land had been turned from prairie into farms. Read this letter from a farmer to understand what this change meant for the animals.

Dear Martha,

Today, I was plowing the new field, and I saw a meadowlark. I really like that kind of bird. I love its song. It’s a good neighbor, too. It eats the insects, and you know we have too many of them. That bird kept flying back and forth. It seemed to be looking for something. Maybe it was looking for its nest from last year. There’s about ten acres of prairie that I’ve left near the road. So I thought the bird would go there. But it flew away. I’m not sure where it went.

I got the whole field plowed today. Tomorrow we’ll put in the seed. This is going to be a great year. I hope you can come to visit this spring. Of course, we’ll have some work for you to do, but it will be good to be together again.