The carbohydrates produced by the plant passes to an animal when the plant is eaten and then may pass to another animal when that animal is eaten. Eventually the energy in the food will be released into the atmosphere as heat. The energy cannot be recycled. For this reason, plants have to constantly produce new carbohydrates from sunlight in order to sustain life.

In plants, photosynthesis occurs in tiny structures in the leaves known as chloroplasts. Chloroplasts contain a pigment known as chlorophyll. The chlorophyll absorbs the sunlight that provides the energy for photosynthesis. All the wavelengths of the sunlight are absorbed, except the green wavelength. This is reflected back, and is what gives plants their green coloration. Chloroplasts are very tiny. A square millimeter of leaf will contain about 500,000 chloroplasts. 

The carbon dioxide used in photosynthesis is brought into the plant through pores in the leaves known as stomata. Stomata are not constantly open, but can be opened and closed when necessary. This keeps the water in the plant from escaping as water vapor. When the stomata are closed, the leaf is watertight. The stomata only open when the plant has sufficient water resources. During dry seasons, many of the plant leaves will die because the stomata are not opening to allow carbon dioxide to enter. 

Water is gathered in a plant by its roots. The cells of the roots have highly porous cell walls, and the water in the soils moves into the roots through the process of osmosis. Osmosis is the process by which water moves from areas of high concentration to areas of low concentration. When the soil has more water in it than the plant's roots, the water will begin to fill the empty space in the roots. Osmosis is more rapid when there is a lot of surface area for the water to cross, therefore the more surface area on the plant's roots, the more water the plant can absorb. For this reason, roots develop root hairs, little tubes that stick out from the roots to provide more surface area. To give an example of how much they add, a four month old rye plant contains approximately 14 billion root hairs. This gives the roots a surface area of over 401 square meters through which to absorb water.

When photosynthesis occurs, the light energy from the sun causes a chemical reaction in the plant. Powered by the sun, carbon dioxide and water combine to form the carbohydrate glucose, a very simple kind of sugar. Some of the light energy is converted into chemical energy and this gets captured in the glucose molecule. This energy can be used by the plant for growing, making new cells, repairing wounds to the plant and allowing all the cells of the plant to synthesize molecules and conduct other necessary chemical reactions.

Much of the glucose is converted into more complex starches, sugars and oils that are stored by the plant for future use. Most of this converted glucose is then stored in the roots or stems of the plant. These are then used by animals as a food source. Some examples of the plants that store energy in this manner are potatoes, carrots, celery, radishes and onions. Some of the food energy is also stored in seeds to give the plant embryo energy to feed off of as it begins to grow and develop. Some of it is stored in colorful, sweet fruit which covers the seeds and is attractive to animals to eat. When an animal eats a fruit, it will also ingest the seeds. These are carried by the animal until they are dropped as waste in a new location. This aids the plant in seed dispersal. Fruits include apples, grapes, oranges and tomatoes.

When an animal eats a plant, some of the food energy from the plant is used by the animal for its life processes, some of it is stored in fat and muscle and what is not digested is lost as waste. When that animal is consumed, some of its energy will be passed on to the animal eating it. If that animal is eaten, some of the energy will pass on to its consumer. Because energy is constantly being used or lost through a food chain, the farther up a food chain one moves, less of the original energy produced by the plant is available. For this reason, there is a limit to the number of organisms a food chain can sustain.

While energy in a food chain has to constantly be renewed, the nutrients in a food chain can constantly be cycled and recycled. Energy has the capability of escaping earth's gravity, whereas nutrients cannot. Luckily for us, the lost energy can always be replaced by the constant burning of the sun. Luckily for us too, nutrients are constantly being recycled by decomposers in the soil. 

Plants, and all living things, need nutrients to make the chemical compounds they need in order to survive. Plants acquire their nutrients from the soil. Minerals and nutrients in the soil will dissolve in the groundwater from which the plant roots receive their water. The same root hairs that draw in water, draw in the minerals and nutrients dissolved in the water. These nutrients, though not specifically used in photosynthesis, are necessary for the plant in order to live.

Along with energy, nutrients too are passed through a food chain. An animal that eats a plant, a herbivore, gets the nutrients from that plant. The nutrients will then be passed on to the animal that consumes the herbivore. When that animal dies, decomposers, such as bacteria and fungi, will break that animal's chemical compounds down into the original nutrients, and these nutrients will be returned to the soil. Then another plant can pick up these nutrient with its roots, and the cycle will begin all over again. 

A wildlife community without plants is an impossibility. Without plants, the other organisms in the community could not get the food energy, nutrients and oxygen they need to survive. Because plants are producers and make these things, they make life possible for all of the other organisms on earth.

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South Carolina Aquarium Spotlight Organism: Spartina Grass
A salt marsh is one of the most productive habitats on earth. An acre of salt marsh can produce from five to ten tons of plants per year. The average wheat field only produces one-and-a-half to five tons of plants an acre per year. The predominate plant in a salt marsh is Spartina grass. Spartina grass helps provide the majority of the food energy, not just for the animals in the salt marsh community, but for the animals in the ocean community as well.

Spartina grass can thrive in an environment, the salt marsh, which most plants cannot survive. Because of this, Spartina grass grows abundantly in South Carolina salt marshes and is of great importance as a producer of food energy from the sunlight. Though some organisms eat the Spartina grass directly, Spartina is most important to the community when it is broken down into detritus. Detritus are tiny pieces of organic material that have been broken down by decomposers. When decomposers, such as bacteria, break down Spartina grass, they release both food energy and nutrients into the water. This detritus helps to sustain the large animal community that lives in the coastal waters of South Carolina. Without the Spartina grass in the salt marshes, many of the fish, crustaceans and mollusks of South Carolina would not be able to survive.