Path of energy and matter through living systems and the physical environment??

Question

I have this science project that is an imaginary space station. You can think of it as a mini Earth. It is same as Earth, but it is just a space station and is much smaller. (Has less species of animals/plants :) ...)

MY question is what does it mean to describe the path of energy and matter through living systems and the physical environment?? I get the energy, they are passed by eating but what is matter? How can matter be passed????? To illustrate the path of energy/matter how should I draw it out? By using a food web or what?

Answer 1

Matter is the stuff that the organisms are made of - the compounds, elements, physical stuff. We are made of matter. Where did the matter in our bodies come from? We got it from our food. We can trace all of our matter back to plants which build molecules from water, carbon dioxide, and minerals the plants absorb from the ground.

I know you've been working on this project for hours tonight, so I'm going to try to help you finish it up.

To describe the path of energy through the living systems and physical environment....
1. You must have plenty of plants or algae to act as producers. The people on the space station will have the most food available to them if they eat plants and not animals. (For instance, if they took rabbits and raised vegetables to feed the rabbits with the intention of eating the rabbits, the people would have ten times as much food if they would just eat the vegetables themselves and leave the rabbits on Earth.) Maybe you are growing the plants hydroponically (in water and not in soil).
2. The plants use sunlight to carry on photosynthesis and make their own food to use for energy. Extra food molecules are stored in the plant cells. The astronauts eat the plants and get energy in the food. Nothing eats the astronauts. So the path of energy is from sunlight to the glucose and other food molecules in the producers to the bodies of the astronauts. If you decide to let them have a couple of rabbits (which I wouldn't) the path would be sunlight --> food molecules in plants --> energy in the body tissues of the rabbits --> energy for the astronauts when they eat the rabbits.

What is the path of the matter in the system? Matter goes in a cycle. It's used over and over. The astronauts can not get any extra matter while they are closed up in the space station, so they have to make do with whatever they took along on the flight.
1. The plants grow and carry on photosynthesis. As they grow, they are adding matter to their bodies. The plants make the molecules for the new cells by using carbon dioxide, water, and minerals from the soil or from the water solution they are growing in.
2. If the astronauts eat the plants directly, the astronauts get the matter (molecules) from the plants. Nothing eats the astronauts. You can always put the rabbits in the sequence before the astronauts.
3. How do we make the matter go in a cycle? The leftover plant parts that aren't edible will be composted (put into a container with some soil mixed in so the dead plant parts will decompose). After the plant parts decompose, the resulting compost or decomposed matter can be used to fertilize the new plants that are growing. So the matter goes in a cycle and is used over and over again. Solid waste or feces from the astronauts can be composted and used in the same way, as well as any droppings from the rabbits.
4. So the path of the matter is:
carbon dioxide/water/minerals ---> turns into plant matter through photosynthesis --> becomes animal matter when the plants are eaten --> parts of plants, animals, wastes are composted and returned to the system to grow more plants --> (arrow back to the beginning)

I don't know what your teacher recommended for illustrating the path of energy and matter, but I think that a food web with arrows tracing the paths would work very well ... especially if you write short explanations next to the arrows. It might be best to make one food web drawing for the energy and a second food web drawing for the matter.