5G – Sizing the biotic factor

Supporting article G: Biotic factor may be very big and also very, very small.

http://www.ehow.com/about_5135640_biotic-factors-ecosystems.html

Biotic Factors in Ecosystems
By Tyler Lacoma, eHow Contributor

In ecosystems, biotic factors are all living organisms and the waste that they produce. This refers to large life-forms such as trees or mammals, small life-forms such as insects and algae, and microscopic life-forms such as bacteria. These are the most diverse and easily changeable parts of ecosystems, subject to the balance of food chains and influenced by disease, pollution and abiotic conditions.

Biotic Factor Definition
1. Biotic factors are all organisms in an ecological setting. Things that are considered alive are biotic factors when studying the cycles of ecosystems and how environments function as a whole. This refers to animals, plants, trees and any materials they directly produce such as waste or falling leaves. The nonliving materials in an ecosystem, such as minerals, gases, liquids and chemicals are referred to as abiotic or non-biotic factors. In some ecosystems, such as jungles, the number of biotic factors is very high while the abiotic factors are relatively simple. In other places like deserts the abiotic factors are predominant and there are few biotic factors, which are all the more valuable because of the scarcity.

Large Biotics
2. Plants and animals that feed on them are the largest biotic factors in ecosystems. Plants can be as small as grass or as large as trees, depending on the area, and many different types of animals live on them. Animals that in turn feed on these animals are even larger, such as hawks, wolves and lions. While these are the most noticeable biotic parts of the ecosystem, they are often the lowest in number, smaller biotics being much more prevalent. These large biotics produce much of the waste that is also considered biotic materials, from leaves to dead bodies.

Small Biotics
3. Small biotics are the smaller organisms in an ecosystem, many of which feed on the waste or living material of the larger biotics. These include lichens, algae, worms and insects, many of which provide an integral food source for the larger predators, including birds and small mammals. These biotics do not produce as much waste as the large animals or trees.

Microscopic Biotics
4. Although by far the smallest biotics, the microscopic organisms are some of the most important. Plankton, viruses and bacteria are all vital microscopic biotic organism. Bacteria can either be helpful, breaking down dead organisms into nutritious matter and helping larger organisms digest food, or harmful, spreading infections. Plankton is a vital resource in ocean ecosystem, and viruses have a tremendous impact on the health of environments, although negative.

Biotic Implications
5. Both biotic and abiotic conditions can affect how an ecosystem thrives. Abiotic factors such as light intensity or what kind of soil is present directly affect biotic systems, but also rarely change. Biotic changes can occur more easily and threaten an ecosystem more completely. A disease or unbalance of predators can change one link of the food chain, which will in turn affect all lifeforms. Abiotic factors are generally changed only by outside interference, such as pollution.