You can build your own miniature ecosystem in a bottle or aquarium to learn about how the plants and animals interact and support one another within the habitat. Cut the top off a plastic soda bottle or use a glass aquarium. Fill the bottom with 2 inches of sand and add water. Plant elodea stalks in the sand and sprinkle duckweed on the surface. Let it set for 24 hours to let the sand settle and the water to clear. Add two to five guppies and a few water snails, depending on the size of your tank. Make daily observations over the next 30 days, noting plant growth, population changes and behavior. Record precise measurements of time, date, size and number. Give descriptive details about color, shape and movement.
Succession of life within a habitat is a slow process, difficult to observe in action, but a miniature forest biome in a jar can speed up the cycle to illustrate what happens when the environment changes. Fill the bottom of a widemouthed jar with 2 inches of dirt and cover it with 3 inches of water. Plant an aquatic plant and place it in a sunny location or under a grow light. Add birdseed or sunflower seeds to the jar twice a week. Let the water evaporate without replacing it and observe the difference in what happens to the seeds and the aquatic plant while there is water in the jar versus when it has evaporated. Draw a conclusion on the effect of flooding and drought on an ecosystem.
Testing polluted, filtered and treated water samples will illustrate the need for responsible management of clean water resources by demonstrating the efficiency and labor involved in purifying water. Fill a small tank or tub with tap water, lake or river water. Prepare six petri dishes by placing a slice of potato on each, labeling them "untreated", "polluted", "strained", "settled sediment", "filtered" and "chlorine treatment." Before treatment and after each step, place a few drops of water on one of the slices. Pollute the water with oil, food coloring, paper scraps, dirt, leaves, clay and coffee grounds. Strain out the large items with a kitchen strainer. Let the sample sit for 24 hours to settle out the sediment. Line a long-stem funnel with filtering paper and layer another funnel with charcoal, sand and pebbles from bottom to top. Pour a cup of the settled water through the two funnel filters into a clean jar. Treat the water remaining in the jar with a couple drops of chlorine and take the last sample. Cover the petri dishes and let sit for a few days and observe the bacterial growth in each dish to determine the efficiency of the water purification process. Make a recommendation regarding clean water practices taking into account the time, cost and effort involved in purification.
The microbes at work in compost make excellent food for your garden. The good news is that it is all-natural and made from scraps that you normally throw away anyway, making it an excellent source of organic plant food. You can start your own compost by layering dry sticks and twigs, grass clippings and soil in an old garbage can with airholes cut in the side. Add dry leaves, dead plants, coffee grounds, eggshells, shredded newspaper, dryer lint, pet hair, bread, garlic skins, spinach, strawberries, twigs, wood chips, beans and rice, as available. Avoid pet and human waste, bones, meat, fat, weeds and diseased plants. Spray the pile with water so it is damp but not soggy, and mix it about once a week to develop airflow for microbial growth. Let the compost heat and develop for three to six months before using to fertilize your garden.
Ecologists working toward habitat restoration seek to understand the optimal growing conditions for the plants within the ecosystem. Ecologists want to create a biologically diverse habitat whose species will support one another. You can experiment with providing different environments for seeds to see which conditions provide the best results in terms of plant growth. Try comparing germinating seeds grown with mulch, with and without soil, or adding ash, tobacco or wood shaving to the soil. Test how soil pH or herbicides or vitamins affect germination and plant growth. Plant seeds in different size containers with different population densities and compare growth rate and plant health.