CYCLES OF MATTER

ENERGY AND CYCLESIn the last module you learned about energy in ecosystems. In this diagram, the sun provides energy to the flower, the flower is energy for the caterpillar. The caterpillar is energy for the frog. The frog is energy for the snake, and the snake is energy for the owl.

ENERGY AND CYCLESIn the end, the owl will become old and will die. Decomposers will break down the owl’s body, and the nutrients and compounds that made up the body will return to the soil. Those nutrients will find their way into plants like the flower, and the process will start over again. We call this a cycle.

CYCLES ARE LIKE CIRCLES

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WATER CYCLEThe water cycle is how rain falls to the ground and then how it gets back to the air to become rain again.

There are some special vocabulary words related to the water cycle…

WATER VAPOR

Water vapor is water that has changed to a gas. You can’t see this water, but you can probably feel it. In the summer, or at a pool, you can get that wet, sticky feeling from the air. That is water in the air.

Did you know the water drops on the outside of a glass are from water vapor in the air?

PRECIPITATIONPrecipitation is just

a long word for snow and rain. Water vapor cools down and turns into droplets making clouds. When a lot of water has built up, the clouds get heavy and water falls back as rain.

COLLECTIONWhen water falls back to earth as precipitation it can end up in lakes, rivers, oceans or on land. On land it will become a part of the ground water and it will be soaked up and used by plants and animals. If it goes to the lakes, oceans and rivers it will begin the water cycle all over again.

EVAPORATION

Evaporation is when the sun heats up water in the rivers, lakes and oceans. When the water heats up it turns to water vapor or steam. When it turns to steam it leaves the bodies of water and goes into the air. Once up high it cools down and becomes water droplets in clouds.

TRANSPIRATIONPlants lose water too. It is similar to people…people sweat when they are hot, and when plants heat up they sweat too. When plants sweat they call it transpiration.

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So the cycle repeats itself. Water evaporates into water vapor and rises into the air. The water cools down and turns into droplets forming clouds. When enough water builds up it rains. The rain collects in oceans, rivers, and on land. The water evaporates from the water and transpires from the plants becoming water vapor again.

CYCLES OF MATTER

There are cycles everywhere in nature. The materials that organisms need in nature are often cycled and recycled. Two very common cycles of matter are the carbon cycle and the nitrogen cycle. Both are important to plants and people alike.

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CARBON CYCLECarbon is an element found everywhere in nature. There is carbon in plants. There is also carbon in diamonds, sugars, “lead” in pencils and gasoline. Carbon is in all living things.

carbon

1) In the carbon cycle plants use carbon dioxide and make carbohydrates during photosynthesis, something you studied in module 4. The carbohydrates (which, remember, have carbon) are stored in plants. 2) When plants get eaten by other organisms the carbohydrates break down and carbon is released when the organisms breathe. Then the cycle starts again.

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Carbon is recycled in others ways, too. Carbon, in some form, is released when dead plants and animals are decomposed or when fossil fuels (products like oil and coil) are burned.

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NITROGEN CYCLENitrogen is another element in nature and it makes

up about 70% of the air we breathe. It is important for plant growth and all life in an ecosystem. The basic process is the same as the carbon cycle. Nitrogen is cycled through the environment with the help of plants and animals, who help keep the nitrogen in balance.

LET’S REVIEW!

Energy is cycled in our ecosystems

SUN PRODUCERS CONSUMERS SUN

Matter is also recycled. Some common cycles of matter are the water cycle, carbon cycle and nitrogen cycle.

Recycling matter is important because there is a limited amount of matter available on earth. If nature did not recycle we would run out of important materials necessary to sustain life.