09. Energy & Matter

Outcomes:

• • be able to explain the movement of energy in a food chain.

• explain the difference between the movement of energy and the movement of matter.

Activity #1:

You are given a copy of the text below. Read it carefully and highlight in different colours the key vocabulary.

"We are surrounded every day by energy and matter. Look around you and out the window. You are using energy to read while the sun outside is giving energy to the plants and grass. Notice the air around you, the soil outside, and think about the food you’ve eaten today (these are all matter!) Energy and matter are two important factors in every ecosystem. Recall that an ecosystem is all the organisms living together along with the nonliving factors in the environment. The matter in an ecosystem includes food, water, shelter, soil, air, etc. and is constantly being changed and recycled through the environment.

Most of the energy that enters an an ecosystem comes from the sun and some of this energy is transferred from one organism to another by way of food chains. Plants and other organisms with chlorophyll in the their cells can capture light energy and use it to make sugar from carbon dioxide and water – this gives the plant energy. This energy can be used by other organisms after it eats the plant or it can be stored in its cells and tissues for later use. The energy stored in the cells of organisms is passed through the ecosystem by way of the food chain. Organisms that are part of the food chain use this energy to carry out their life processes such as hunting, eating, reproducing, caring for their young, etc.

As energy is passed from one organism to the next, some of it is lost to the environment as heat. For example, only 10% of the energy that a rabbit contains is passed to the fox that eats it. This process forms an energy pyramid where the amount of available energy is greater at the bottom and decreases as the number of organisms increases. For example, energy stored in grass would be at the bottom of an energy pyramid (largest amount of energy). As a rabbit eats the grass, some of the energy in the grass is lost as it’s being transferred to the rabbit. Then, as a fox eats that rabbit, even more energy is lost during the transfer from the rabbit to the fox. As the number of organisms in the food chain increases, the amount of available energy decreases.

While energy is being transferred in an ecosystem, matter also moves in cycles through the environment getting reused over and over again. A great example of this is the carbon dioxide-oxygen cycle. Trees produce oxygen that is taken in by living things in the air. Those living things then release carbon-dioxide as a waste product which the trees take in to and use for photosynthesis to occur. Nitrogen is another important element that is recycled throughout an ecosystem. Dead plants and animals release nitrogen compounds into the earth and then plants can take in those compounds through their roots. The nitrogen compounds are then transferred to the organism that eats the plant and the process starts all over again. This is called the nitrogen cycle. Bacteria that lives in the soil also help with this process by a process called nitrogen fixation or changing the nitrogen gas in the air into the nitrogen plants can use."

Activity #2:

First, cut out and glue down the ENERGY & MATTER flip flap. On and under the flip flaps, record information you learned about energy and matter in an ecosystem (why it’s important, how it works, what it is, etc.)

Second, cut out and glue in the energy pyramid. Starting at the bottom, draw in organisms at each level to show an example of how the amount of energy decreases as the number of organisms in the food chain increases.

Next, cut out the pictures to create the carbon dioxide-oxygen cycle as well as the nitrogen cycle. Add in arrows and label all the parts of the cycles.

Finally, respond to the writing prompt and add any other information your teacher instructs.

Next Lesson: Sampling Techniques