The ecosystem is the set of species in a given area that interact among themselves. The species of the ecosystem, including bacteria, fungi, plants and animals, are dependent on each other. The relationships between species and their environment determine the flow of matter and energy within the ecosystem. Ecosystems have no particular size. An ecosystem can be as large as a desert or a lake or as small as a tree or a puddle.Ecosystems are made up of 3 different categories: energy flow, water flow, mineral flow. If there isn't enough light or water or if the soil doesn't have the right nutrients, the plants will die. If the plants die, animals that depend on them will die. If the animals that depend on the plants die, any animal that depends on those animals will die. Ecosystems in nature work the same way. All the parts work together to make a balanced system!

Energy Flow:
The transformations of energy in an ecosystem begin first with the input of energy from the sun. Energy enters the biological system as light energy and it is transformed into chemical energy in organic molecules by photosynthesis and respiration, and is converted to heat energy. So plants are absorbing the energy from the sun and helping them grow and develop. This energy is scattered, meaning it is lost to the system as heat. Once it is lost it cannot be recycled. Without the continued input of the suns energy, biological systems would quickly begin to shut down. Energy flows through the ecosystem in the form of carbon-carbon bonds. When respiration occurs, the carbon-carbon bonds are broken and the carbon is combined with oxygen to form carbon dioxide. This process releases the energy, which is either used by the organism (to move its muscles, digest food, excrete wastes, think, etc.) or the energy may be lost as heat.


Water Cycle:
Another process of the ecosystem is the water cycle.Without water there would be no life. Water is a large percentage of the cells that make up all living organisms. In the water cycle, energy is supplied by the sun, which drives evaporation whether it is from ocean surfaces or from treetops. Water constantly cycles around between bodies of water, the sky, and the earth. The sun with the help of the wind, also supplies the energy which drives the weather systems, which moves the water vapors, in the form of clouds, from one place to another, or else it would only rain over oceans. Precipitation occurs when water condenses from a gaseous state in the atmosphere and then falls to earth. Evaporation is the reverse process where the water becomes gaseous. Once the water condenses, gravity takes over and the water is pulled to the ground. Gravity continues to occur, either pulling the water underground across the surface, gravity goes on to pull water lower and lower until it reaches the oceans. Oceans are salty because any erosion of minerals that occurs as the weather runs to the ocean will add the mineral content of the ocean water. Water can’t leave the oceans except by evaporation, and evaporation leaves the mineral behind. This is why rain and snowfall are relatively clean water. The most important factor in the way the water cycle works is the soil, particularly the soil surface; where the earth meets the air. In plants, or grass water is drawn in at the roots and moves to the leaves where it quickly evaporates. This special case is called transpiration because it is responsible for so much of the water that enters the atmosphere.

Mineral Flow:
  • Carbon Cycle:
All life is based on the element carbon. Carbon is essential component of proteins, fats, and carbohydrates, which make up all organisms. The carbon cycle is a process by which carbon is cycled between the atmosphere, land, water, and organisms. Ecosystems gain most of their carbon dioxide from the atmosphere. When consumers eat producers, the consumers obtain carbon from the carbohydrates. As the consumers break down the food during cellular respiration, some of the carbon is released back into the atmospheres carbon dioxide.


  • Nitrogen Cycle:
The only organisms that can fix atmospheric nitrogen into chemical compounds are a few species of bacteria know as nitrogen fixing bacteria. Nitrogen fixing bacteria are crucial part of the nitrogen cycle, a process in which nitrogen is recycled between the atmosphere, bacteria and other organisms. Nitrogen fixing bacteria live within nodules on the roots of plants called legumes. Legumes include beans, peas, and clover. The bacteria use sugars provided by the legumes to produce nitrogen containing compounds such as nitrates. The excess nitrogen fixed by the bacteria is released into the soil.In the nitrogen cycle, nitrogen moves between the atmosphere and living things. After nitrogen cycles from the atmosphere to living things. After nitrogen cycles from the atmosphere to living things, nitrogen is then returned to the atmosphere with the help of bacteria. After decomposers return the nitrogen to the soil, bacteria transform a small amount of the nitrogen into nitrogen gas, which then returns to the atmosphere and ecosystem, most of it stays within the ecosystem, cycles between organisms and the soil, and it constantly reused.


The sun's heat helps water evaporate and return to the atmosphere where it is cycled back into water. The heat also keeps plants and animals warm. Without light from the sun there would be no photosynthesis and plants wouldn't have the energy they need to make food.The ultimate source of energy (in most ecosystems) is the sun. The ultimate fate of energy in ecosystems is for it to be lost as heat. Energy and nutrients are passes from organism to organism through the food chain as one organism eats another. Decomposers remove the last energy from the remains of organisms. Inorganic nutrients are cycled, energy is not. If you understand how energy moves through an ecosystem, you are in good shape because then you will have an idea of how ecosystems are balanced, how they may be affected by human activities, and how pollutants will move through an ecosystem.