Changes in the Environment By: Cammie’s Corner

Many living and nonliving things make up an ecosystem Many living and nonliving things make up an ecosystem. These many parts are all connected. A change in one part of an ecosystem can cause changes in many other parts. The change is like a stone thrown in a pond. It starts a ripple that spreads out across the water. A change spreads throughout an ecosystem in the same way.

Environments & Natural Changes The environment is everything t hat is around a living thing. There are many different types of environments on Earth. Some are deserts, forests, polar regions, swamps, rivers and streams. Different organisms live in different environments because of the features of each environment.

Environments change often. Many of these changes are natural changes. Some changes are very slow, taking place over a long period of time. Other changes happen fast, like floods and fires. When an environment changes, it affects the plants and animals that live there.

In order to survive, living things need many things. A material for Earth that living things use to survive is called a resource. Resources include food, water, sunlight, soil and air. Living things also need space to live. Plants need somewhere to grow. Animals need a safe place to live, called shelter. Changes to an area affect how many resources there are for animals and plants to use.

There are many different ways that an environment can change. Example: the amount of water in an environment can increase. A flood happens when a river or other body of water overflows.

This can happen if there is a lot of rain or snow that melts This can happen if there is a lot of rain or snow that melts. The soil becomes muddy. Plants may be washed away or destroyed. When that happens, animals may be left without homes or food. Many of these animals may leave to look for food or die out. This can make room for new organisms to move in to the ecosystem. With time, the entire ecosystem may change.

Fires also change environments quickly. A fire can destroy many trees, other plants and animals. Many animals, such as insects, birds, and squirrels, make their homes in trees. Many animals eat the seeds and berries of plants.

When the plants and trees are gone, these animals lose their food and shelter. The animals that survive the fire must live in other areas until the plants grow back again and many may die. New kinds of plants and animals may take the place of those lost.

Sometimes the amount of water in an environment decreases. During a drought, very little rain falls. Over time, the soil becomes dry. Plants need water to survive. Many plants may die because there is not enough water. Animals like fish that live in water may die. Other animals may die, too, if they cannot find water to drink or plants to eat.

Population Changes A population is a group of living things of the same kind living in the same area: Many different populations live in an area. Populations affect each other in many ways. They may compete, or fight, for resources. Examples: Both deer and squirrels eat the acorns that fall from oak trees. Dandelions and grass plants compete for space in your lawn.

Members of the same population also compete for resources. If one animal or group gets too much of the resource, there may not be enough left for the other animals or group. Some members of the other group might die.

Predators and Prey One population may feed on another: Example: hawks feed on mice. A hawk is a predator, an animal that hunts other animals for food. The animal the predator hunts is called the prey.

A predator population and a prey population affect each other: When the prey population is large, there is a lot of food for the predators. They are well fed and have many babies. So the predator population gets larger. When there are more predators, they eat more prey. So, the prey population gets smaller. Then there is less food for the predators.

Some predators cannot find enough to eat so they leave the area or die. The predator population gets smaller. When there are fewer predators, they eat less prey. Then the prey population grows larger again. The two populations get larger and smaller in a pattern that repeats.

The graph shows the sizes of two populations. The moose is the prey The graph shows the sizes of two populations. The moose is the prey. They wolf is the predator. Look at what happened between 1965 and 1970, and between 1985 and 1990. As the wolf population became very small, the moose population got much larger.

Habitat Reduction A habitat is the place where a living thing is found naturally. Its habitat is where it lives. Example: The part of a forest where a group of deer live. Many different living things share the same habitat, including humans.

Humans affect natural habitats in many ways:   People make habitats smaller and even destroy them. People clear land in order to build new homes, make roads, grow crops, and raise animals. This use of land for buildings or farming is called land development. People remove many of the living and nonliving resources from the area. As a habitat gets smaller, it is harder for living things to find the resources they need. They are left without food and shelter and often do not survive.

A change in one part of an environment can affect all the living things in it: A change in the nonliving parts of the ecosystem can affect the living things too. A flood, a fire, a drought, or land development can mean fewer plants or producers. Fewer producers mean fewer consumers—and fewer prey. Fewer preys lead to fewer predators.

Did you know. Like people, beavers greatly change their environment Did you know? Like people, beavers greatly change their environment. Beavers cut down trees and build dams across streams. They stop water from flowing, which causes a pond to form. Many plants and animals in their ecosystems are affected by these changes.

Study the picture below Study the picture below. How might this environment change if there were a drought?

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