Transcript for:
Understanding Food Chains and Ecological Networks

God created two great lights. The greater light to rule the day and the lesser light to rule the night. The source of light, the sun, spills over the horizon each daybreak, shining its heat and light on the world below.

Every living thing needs energy to survive. It takes energy for you to jump, laugh or sing. Where does all that energy come from?

It comes from the food that you eat. The lettuce and tomatoes you eat in a salad were grown using water, soil, and the light and heat energy from the sun. A food chain follows the sequence of how the energy from the sun transfers from one living thing to another.

Every living thing belongs to a food chain. This simple food chain shows the sequence of how the sun gives energy to the lettuce, and how that energy is then transferred to the person who eats the lettuce. Vast amounts of various plants cover the earth.

Grass, sequoia trees, moss, and even seaweed in the ocean all harness energy from the sun and use it to create food through a chemical process called photosynthesis. Plants that produce their own food are called producers. or autotrophs.

All food chains start with autotrophs because they not only produce their own food, but they also provide food for other animals. Unlike plants, animals cannot produce their own food. They need to eat to have the energy to run, move, and grow.

Animals are referred to as consumers or heterotrophs because they consume or eat food. to get the energy they need. Let's look back at our simple food chain. The lettuce is a producer or autotroph, and the person eating the lettuce is a consumer or heterotroph.

Now, let's examine another type of food chain. This food chain begins with a flower. A flower is a producer or autotroph.

Then a honeybee comes along and eats from the flower. The honeybee is a consumer. Because the honeybee is the first consumer, it is called the primary consumer.

The honeybee uses the energy from the flower to move and grow. Now, the honeybee is eaten by a skunk. The skunk is known as a secondary consumer because it is the second animal to consume in the food chain.

Animals who are secondary consumers are also known as carnivores, animals that eat other animals. If a bear eats the skunk, the bear is known as a tertiary consumer, or the third tier of consumer in the food chain. Our food chain example ends here because bears are known as apex predators, which means they have no natural predators and are at the top of their food chain.

One more important aspect of a food chain is what happens when a living thing dies. Going back to our food chain example, eventually the bear will die. Scavengers, such as red weaver ants, vultures, or wild dogs, help break down the material, and decomposers and detritivores, such as worms, Maggots, flies, mushrooms, and bacteria will decompose the bare matter, and ultimately, the nutrients will return to the soil. In the Bible, we read, For dust thou art, and unto dust shalt thou return.

Producers will then use the nutrients from this soil, along with the water and the energy from the sun, to continue the cycle of the food chain. Because animals eat more than one type of food, it can get complicated to depict all the food chains at one time. When we put one or more food chains together in a diagram, we can show the interconnection of animals and other living things, and how energy travels from one thing to another. This is called a food web.

A food web is a diagram that illustrates in a more sophisticated way how food and energy transfer through an ecosystem. The arrows on a food web indicate the direction in which the energy is transferred. The heads of the arrows point to the animal that does the eating, and the tails of the arrows show what's being eaten.

Countless varieties of plants and animals exist on the land and in the ocean, so numerous food chains and food webs exist in each ecosystem. Let's explore two different food webs and the animals and plants found in each. A wooded forest food web may contain grass, berries, robins, foxes, wolves, owls, squirrels, mice and more, decomposers and detritobores, might include earthworms, fungi, bacteria, wood lice and other organisms.

A marine food web may contain phytoplankton, seaweeds, sea urchins, fish, sea otters, birds and decomposers and detritivores such as sea cucumbers, marine worms, mollusks, crabs and bacteria. Both of these food webs depend upon the sun, which allows producers to use energy from the sun to produce food. This energy is transferred to consumers and then to decomposers and detritivores. Food chains and food webs are a beautiful way to organize, envision, and describe God's grand design for each of his creations.

Life on planet Earth thrives because the sun's energy is used by plants, animals, and decomposers to complete. The Cycle of Life