Organisms need many resources to survive. These resources include water, sunlight, soil, and air. Ecosystems change when resources change.
Drought is a long period of time with little or no rain. During a drought, plants and animals may die. Diseases can also change an ecosystem. Beginning in the 1930s, Dutch elm disease killed millions of elm trees across North America. Animals that lived in these trees lost their homes.
Fire can also change an ecosystem. So can overpopulation, which means there are too many of at least one kind of living thing. An overpopulation of kangaroos is a problem in Australia. They compete with livestock for food and water.
Pollution happens when harmful substances are added to Earth’s water, air, or land. Polluted water comes from wastes dumped into rivers, lakes, or oceans. The water can become too dirty to use. It can also kill plants and animals that live in it.
In 1989, a ship spilled 11 million gallons of oil into the ocean off Alaska. The oil killed hundreds of thousands of animals. Pockets of oil are still present today.
Air pollution comes from cars and factories. Burning gasoline, coal, and other fuels can add acids to the air. The acids fall to Earth as acid rain. Acid rain can ruin lakes, forests, soils, and crops.
Waste gases from cars, homes, and factories may join with water in the air to form smog. Smog hangs in the air like a cloud. It can make the air hard to breathe.
Acid rain, smog, and trash can all pollute the soil. This is called land pollution. Polluted land can harm the plants and animals that live on it. It is ugly, too.
To keep ecosystems healthy, we must use resources wisely. You can help in many ways. Do not waste energy. Never dump trash on the land or in water. Ride in a bus or train instead of a car. You also can support laws that help control pollution. These laws include the Clean Air Act and the Clean Water Act.
There are several things that may cause changes to the ecosystem. One event is drought which is a long period without rain or precipitation. Plants may die during a drought. Diseases such as the Dutch Elm Disease destroyed about 43 million trees. The Dutch Elm Disease also harms insects and animals that make their homes in these trees. The trees also give off oxygen, and their destruction would decrease the oxygen in the air. Soil erosion and fire can change an ecosystem. Overpopulation can also alter the ecosystem. Overpopulation occurs when there are too many of at least one kind of living thing. This means resources will be depleted for plants and animals.
Pollution occurs when harmful substances are added to Earth’s air, water, or land. Water pollution is caused by wastes from homes and factories. Water pollution can kill plants and animals. Air pollution comes from forest fires, volcanoes, cars and factories. Burning gasoline, coal, and fuel can cause acid rain. This can ruin lakes, forests, soils, and crops. It can harm plants and animals. Land pollution such as acid rain, smog, trash, and chemical wastes can harm land.
To reduce pollution, you should use resources wisely. You can conserve energy, clean up litter, recycle, and not dump wastes into the water.