Energy in an ecosystem

-Organisms like humans obtain our energy by breaking down molecules and utilizing their chemical energy. Specifically, we rely on oxidation of these molecules to obtain electrons which drive the chemical reactions in our body. Such organisms are known as chemotrophs. Chemotrophs that have to ingest organic matter (us) are called chemoheterotrophs. Chemotrophs that can make everything they need from carbon dioxide rely only on inorganic matter and are called chemoautotrophs (certain types of bacteria). Plants, on the other hand, obtain their energy by converting solar light energy into chemical energy. Light and the oxidation of water provide energy to synthesize organic molecules from carbon dioxide. These organisms are known as phototrophs.

-All energy on earth (ecosystem wise) comes from the sun. This is absorbed by the plants at the highest energy intake, who then use this provide oxygen for us air-breathers and also produce themselves. Most plants are then eaten, and this original energy from the sun enters the ecosystem--think "food chain". However, it's about a 10% energy loss each step, which is why there are fewer carnivores than plants. Once plants/animals die and decompose, that energy is transferred pack into the soil, humus, or eaten again, so even at death the energy is still moving through the ecosystem.

-A food web is a graphical description of feeding relationships among species in an ecological community, that is, of who eats whom (Fig. 1). It is also a means of showing how energy and materials (e.g., carbon) flow through a community of species as a result of these feeding relationships. Typically, species are connected by lines or arrows called "links", and the species are sometimes referred to as "nodes" in food web diagrams.

-he trophic level of an organism is the position it occupies in a food chain.A food chain represents a succession of organisms that eat another organism and are, in turn, eaten themselves. The number of steps an organism is from the start of the chain is a measure of its trophic level. Food chains start at trophic level 1 with primary producers such as plants, move to herbivores at level 2, predators at level 3 and typically finish with carnivores or apex predators at level 4 or 5. The path along the chain can form either a one-way flow or a food "web". Ecological communities with higher biodiversity form more complex trophic paths.

 

-A Biomass is a biological material produced from living or recently living organisms. Like trees, animals, and garbage: The total mass of living matter within a given unit of environmental area.Plant material, vegetation, or agricultural waste used as a fuel or energy source.Biomass is typically used as a renewable energy source. They do this through burning it or turning it into fuel. It still is damaging to the atmosphere though, and to the grounds of where the plant material was collected.

-A pyramid of numbers is the model that shows the individuals levels in a food chain or in a food web.