Lesson 4 – Role of Animals - We learned the affect of animals on the environment. We learned the importance of animals as food for us and other animals. We learned that we get eggs, hamburgers, cheese, milk, and many other foods we eat from animals. Then we learned that some animals such as sheep, goats, and cows are grazers, which means they eat plants. If too many grazers are in one place, they can eat too many plants. Then, there are not enough plant roots to hold the soil in place, and it blows away. We learned some helpful effects of animals on the environment. For instance, bats eat insects keeping the number of biting insects down. Then we learned that animal wastes add nutrients to the soil making it good for growing plants. We learned that animals hunting other animals keeps the population down so the number of living things in one place isn’t too large. We know that bees and butterflies spread pollen to help plants reproduce. Then we learned that sometimes animals can be brought into an environment where they didn’t exist and take food and space from animals that are native to the environment. As a result, the numbers of native animals decrease. An example is the zebra and mussels that were brought into the Great Lakes by accident.