Ecology Types of ecological interactions M. Saadatian

Types of ecological interactions competition predation parasitism Mutualism Amenalism commensalism symbiosis

Competition – two species share a requirement for a limited resource  reduces fitness of one or both species Competition is an antagonistic interaction between individuals, groups, animals, etc. for territory or resources. It arises whenever two or more parties strive for a goal which they do not want to share. Competition occurs naturally between living organisms which co-exist in the same environment. Example: competition for light, for nutrients for water

Amensalism Amensalism is an interaction in which one organism is harmed, while the other is unaffected, and not benefited. Most frequently this occurs when one organism exudes a chemical compound that is detrimental to another organism. Plant roots exude many compounds that either attract or repel bacteria, fungi or the roots of other plants allelo compounds = allelo pathogens Allelopathy

Chemical competition (Allelopathy) Allelopathy is a biological phenomenon by which an organism produces one or more biochemical that influence the growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have beneficial (positive allelopathy) or detrimental (negative allelopathy) effects on the target organisms. Allelochemicals are a subset of secondary metabolism.

Predation – one species feeds on another  enhances fitness of predator but reduces fitness of prey Predation describes an interaction where a predator feeds on an organism that is attacked. The act of predation must result in the death of its prey and the eventual absorption of the prey's tissue through consumption. Other categories of consumption are herbivory (eating parts of plants), which is not considered predation. Clear examples of predation are insectivorous plants. But there are other plants that kill plants by stealing their light. herbivory is a form of predation

Symbiosis – two species live together  can include parasitism, mutualism, and commensalism

Parasitism – one species feeds on another  enhances fitness of parasite but reduces fitness of host A parasitic plant is one that derives some or all of its sustenance from another plant. Parasitic plants have a modified root (haustorium) that penetrates the host plant and connects to the xylem, phloem, or both. Animal parasites are generally much smaller than their host; both are special cases of consumer-resource interaction. This does not apply to plant parasites. The Greater Dodder or the European dodder (Cuscuta europaea) is a parasitic plant which belongs to the family Convolvulaceae. It grows on Asteraceae, Fabaceae, Chenopodiaceae, and other herbaceous plants

Mutualism – two species provide resources or services to each other  enhances fitness of both species Neutralism is where two species have no interaction at all; a pink dolphin and a canopy lizard could be an example of neutralism.

Commensalism – one species receives a benefit from another species  enhances fitness of one species; no effect on fitness of the other species Commensalism benefits one organism while the other organism is neither benefited nor harmed. It occurs when one organism takes benefits by interacting with another organism by which the host organism is not affected. Example: mosses, ferns, orchids