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Understanding how all energy in a food web begins with sunlight.
Did you know that every time you run, jump, or even breathe, you are using 'star power' that traveled 93 million miles to reach you?
Think of the Sun as a giant, glowing battery in the sky that never runs out. It is the primary source of energy for almost every living thing on Earth. The Sun sends energy down to us in the form of light and heat. Without this energy, our planet would be a dark, frozen rock where nothing could grow. Even though you can't 'eat' a sunbeam for lunch, the energy inside your food actually started out as sunlight! We can represent this starting point as the beginning of every energy path:
Quick Check
If you eat an apple, where did the energy inside that apple originally come from?
Answer
The Sun.
Plants are amazing because they act like living solar panels. They are called producers because they 'produce' their own food. They use a special process called photosynthesis. During photosynthesis, plants take in sunlight, water, and air to create a type of sugar. This sugar is the plant's food, and it stores the Sun's energy in its leaves, stems, and roots. Because plants are the only ones who can turn sunlight into food, they are always the first living link in a food chain.
1. A sunflower leaf catches sunlight. 2. The leaf uses that light to turn water and air into sugar. 3. The sunflower uses that sugar to grow tall. 4. The energy from the sun is now stored inside the sunflower.
Quick Check
What is the name of the process plants use to turn sunlight into food?
Answer
Photosynthesis.
Since animals (including humans!) cannot make food from sunlight, we have to eat plants or other animals. We are called consumers. When an animal eats a plant, the Sun's energy moves from the plant into the animal. It's like a relay race where the 'energy baton' is passed along. We use arrows to show this flow: . The arrow always points in the direction the energy is moving!
Imagine a forest where a thick cloud of dust blocks the Sun for a year. 1. The plants cannot perform photosynthesis and die. 2. The deer have no plants to eat and must leave or they won't survive. 3. The wolves have no deer to eat. This shows that even 'meat-eaters' depend on the Sun!
Which of these is considered a 'producer'?
In the energy flow , what does the arrow represent?
True or False: Animals can make their own food if they stay in the sun long enough.
Review Tomorrow
Tomorrow, look at your dinner plate and try to trace the energy of one item back to the Sun. For example: Chicken Corn Sun!
Practice Activity
Go outside and find one 'producer' and one 'consumer'. Draw a picture showing how energy moves between them starting from the Sun.