Amensalism

Amenalism

· In this one organism restricts the growth of other organism

· This phenomenon is known as allelopathy (in plants )/ antibiosis/ biological antagonism

· Examples:

1. Penicillium secretes penicillin which kills bacteria

2. Streptomyces an actniomycetes inhibits growth of bacteria. This is extracted and used as anti-biotic

3. Roots of black walnut secrete Juglone which is toxic to other plants like apple and alfalfa

4. Convolvulus arvensis inhibits the growth of wheat

Amensalism is a type of biological interaction. It is an association between two organisms if different species where one is adversely affected and the other stays unaffected. Humans also have amensal relationships with numerous other species. In almost all such cases, the other species suffer a detriment as a result of one or more human activities. For example, air pollution caused by automobiles, electricity generating s tations, or metal smelters often causes severe damage to lichens and plants in the affected area, whereas humans receive no direct benefit from this relationship. Another example is birds, mammals, and other wildlife that suffer habitat loss when forests are clear-cut to provide wood for industrial purposes. Although humans derive economic benefits from harvesting the timber, there are no particular benefits to people from the damage caused to habitat.

In this one organism restricts the growth of other organism

· This phenomenon is known as allelopathy (in plants )/ antibiosis/ biological antagonism

· Examples:

1. Penicillium secretes penicillin which kills bacteria

2. Streptomyces an actniomycetes inhibits growth of bacteria. This is extracted and used as anti-biotic

3. Roots of black walnut secrete Juglone which is toxic to other plants like apple and alfalfa

4. Convolvulus arvensis inhibits the growth of wheat

A comment example is Penicillium and bacteria. The secretion of penicillin i.e.penicillium kills the bacteria but it remains uneffected i.e. not harmed nor benefited.

Other example is some trees whose secretion kill the small plants near them. Like Black walnut secrete Juglon destroys small plants near it.

This is a lovely question. In most ecology textbooks, ammensalism is defined as interactions of populations of different species in which one is affected negatively and the other is unaffected by the interaction (-/0). The usual classification of different types of these interactions is given in Pianka’s book, “Evolutionary Ecology”:

Competition, –/ –, Each population inhibits the other, negative effect for both

Predation, parasitism, +/ –, Population A, the predator, parasite, and Batesian mimicry or mimic, kills or exploits members of population B, the prey, host, or model

Mutualism, Müllerian mimicry, +/ +, Interaction is favorable to both (can be obligatory or facultative)

Commensalism, +/ 0, Population A, the commensal, benefits whereas B, the host, is not affected

Amensalism, –/ 0, Population A is inhibited, but B is unaffected

Neutralism, 0/ 0, Neither party affects the other.

In the above classification we humans judge the type and strength of the interaction on the basis of the outcome effect on population growth. The fact that their type (or even their existence for that matter) is defined by human observation of the outcome has led to some criticism of these concepts.

First, whether or not the interaction is positive, negative, or neutral for some species population is not always observed in terms of population growth that is independent of other factors. Moreover, the actual mechanisms of these effects are also not always observed and more importantly, when humans do observe a mechanism, we don’t necessarily observe all such mechanisms. There may be mechanisms of interaction that we haven’t observed and the outcome for population growth that we do observe may not always be attributable to the mechanisms we think are producing the outcome.

Prior to observing the outcome, we have no knowledge regarding the organisms and their effect on each other. Then we look for an effect and interpret it and its existence through human ‘lenses’.

For amensalism, I offer the following questions: If populations of two species interact, on what basis do we conclude that there is no positive or negative effect? If we construct a carefully designed experiment in which only one factor is not controlled and we subsequently observe no effect, positive or negative, do we risk failure to detect offsetting ‘controlled’ factors? In that case, are we sure enough with regard to our observation that we can conclude that the interaction is an example of amensalism? Really?

Alternatively, do we assume that there can be no interaction that is not either positive or negative in effect to one or the other populations?

Finally, in the real world, can you think of many species populations that ONLY interact with one other species population? Are you sure?

“The suspense is terrible. I hope it will last.”

PARASITISM (+/-) is a close association between two living organism of different species which is beneficial to one (the parasite) and harmful to other (the host).

The parasite obtains food and shelter from the host. Parasitism mode of life ensures food lodging and meals.

PREDATION (+/-) is a a relationship between a Predator and a Prey in which the predator is a free living organism which catches and kills another species for food. They do not get shelter from prey.

Predators keep prey population under control and maintains ecological balance. They also acts as 'conduits' for energy transfer across trophic level.

Populations interact owith each other and may have some positive ir negative or may be no effect on each other.

Amensalism is a kind of interaction in which one organism is negatively affected or may get destroyed whereas the other remain neutral or unaffected.

Here is an example:

Black walnut produces a toxin, called"junglone"that prevents the growth of other plants around it, thus reducing competition in survival.

The substance deprives weaker plants of the energy required for photosynthesized production. The symptoms of the affected plants are the yellowing in the leaf and wilting, that lead to the death of the same ones.

In ammensalism, one microbial population growing on a substrate is inhibitory to the other population. this relationship is based on the production of certain microbicidal chemicals or antibiotics. once organism establishes itself within a habitat, it prevents other population from surviving in that habitat

some examples are: oxidation of sulphur by Thiobacillus thiooxidans which produces sulphuric acid which lowers aquatic ph thereby inhibiting many other microbes.

Amensalism, association between organisms of two different species in which one is inhibited or destroyed and the other is unaffected.

There are two basic modes: competition in which a larger or stronger organism excludes a smaller or weaker one from living space or deprives it of food, and antibiosis, in which one organism is unaffected but the other is damaged or killed by a chemical secretion.