Amensalism

Introduction

Life forms of the planet have a variety of relationships. Some of them could be positive where both or either of the participants benefits or they could be negative whether at least one of the participants is harmed. These can be mutualism, commensalism, parasitism, ammensalism, etc. These relationships have a significant effect on the ecosystem. In this tutorial, we would be discussing more on ammensalism in which one of the participants is harmed while the other remains unaffected.

What is Ammensalism?

We can define ammensalism as a two-species interaction in which one species has a detrimental impact on the other, while the second species has no discernible impact on the first. For example, when large terrestrial vertebrates walk, they destroy grass and small terrestrial invertebrates by stamping on them. Amensalism is one of the stages of evolution because natural selection favours creatures that can efficiently collect nutrients and energy for survival.

Examples of Amensalism

• The interaction between grasses and trees is another example of amensalism. Grasses are low-growing plants that grow next to trees. The roots of trees compete with the roots of grasses for nutrients in the soil, and the trees usually win. The grasses are unable to compete for sunlight with the trees, and as a result, they frequently perish as a result of this competition.

• The interaction between lions and zebras is one of the most well-known examples. Lions are predators that hunt on zebras, and zebras are prey that lions kill and consume. This is an amensal interaction between lions and zebras because the lions benefit from the relationship while the zebras do not.

• The mosquito and humans have a relationship. This relationship helps the mosquito since it gets to feed on the person's blood, but the human is unaffected because the mosquito usually does not spread diseases.

• A prominent example of such interaction can be seen in LAB (lactic acid bacteria) metabolism, which is designed to maximise acid generation rather than growth.

• Another instance is the production of antibacterial compounds like microbes, which are useful in mixed-culture population dynamics and are produced by various food-fermenting LAB.

• Amensalism is a term used to describe highly asymmetric antagonistic relationships, such as those between ibex (Capra pyrenaica) and weevils of the genus Timarcha that prey on ibex (Capra pyrenaica). A similar-looking bush in controlled tests, excluding ibex increased the number of weevils, but weevils had no impact on ibex. Ibex impacted weevils in two ways: unfair competition and unintended predation, with the overall number of weevils developing per bush more than four times higher in shrubs without ibex than in shrubs with ibex. In other words, while the weevil's presence has little effect on food availability, the presence of ibex has a significant detrimental influence on weevil populations because they consume vast volumes of plant matter and frequently ingest the weevils that live on it.

• Smaller species can only use holes that larger species can't, implying that birds with nests have a taxonomic pyramid when it comes to tree holes. According to some researchers, certain small birds have been seen to recognise European starlings (Sturnus vulgaris) as attackers and to show aggression toward them.

• Tagetes produce toxins that are harmful to soil nematodes.

• Weeds cannot thrive near smoother crops such as barley, sorghum, and sunflower. Smoother crops are unaffected, but weeds suffer losses.

• Trichoderma and Aspergillus: Trichoderma is a fungus that inhibits the growth of Aspergillus. Trichoderma is employed as a bio-control agent in organic farming for this reason.

Modes of amensalism

Amensalism comprises two modes, namely, Competition and Antibiosis.

Competition

Commensalism describes an association in which one species benefits while the other is neither benefited nor injured. It can be defined as a relationship between two species that are competing for survival. A larger, faster and stronger creature denies a lesser, inferior one food or shelter. This rivalry arises from the reality that the world's resources are finite, and there isn't enough for everyone.

Competition between organisms of the same species can occur when both organisms are competing for survival. It is divided into three types as shown below.

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Some examples of Competition are

Goat and insects

Goats and grasshoppers are both herbivores with the same particular habitat. As just an outcome, there is competition between the two varieties for sources of food. Plants, grasses, and insects are eaten by goats in the same way they are by sheep. For a reason, the insects' food supply is limited. The goat is unaffected by the interaction because its absence has no effect on it, but the insects lose a substantial amount of food supplies. This is a type of competition in which stronger species have an adverse effect on the growth of weaker species in the same ecological niche.

Larger and smaller fishes

Smaller fishes compete with larger fishes for food resources in aquatic settings. Phytoplankton and zooplankton are two types of fish that feed on phytoplankton and zooplankton in the ocean. The larger fishes can easily locate and consume these nutrients, making them scarce for the smaller species. This is a sort of interspecies competition in which the interaction between larger and smaller fishes has a negative impact on the smaller fishes.

Antibiosis

It is characterised as a situation in which one organism is untouched by a chemical release while the other is damaged or destroyed. It is derived from the French word 'antibiosis.' Vuillemin created the term in 1889-1890 to describe an adversarial connection among organisms in an ecosystem. A chemical release from another organism can either harm or kill an organism. This form of interaction is found in both prokaryotes and eukaryotes, and it has been investigated for its ability to protect humans from a variety of infectious infections. A penicillium is a classic antibiosis example. Penicillin, which is produced by the bread mould Penicillium, has a lethal effect on bacteria. As a result, it's become a highly effective antibiotic against bacterial infections. Another example is black walnut and herbaceous plants. Juglone is a chemical produced by black walnut (Juglans nigra) that has an inhibitory action on different herb species growing in the soil's root zone. The walnut plant produces the chemical as a form of defensive mechanism against various plant pathogens.

The secretion affects the herb plants that grow in the surrounding soil, but the walnut species is untouched.

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Conclusion

Amensalism exhibits the interaction between two species in which one species harms the other, and the organism itself remains unaffected. Antibiosis and competition are the two types of amensalism observed. This type of interaction helps in controlling harmful organisms. It is an example of asymmetric and non-symbiotic interaction.

FAQs

Q1. What is the sign of amensalism?

Ans: Amensalism is a type of relationship in which one partner is inhibited while the other is mostly unaffected. It is indicated by the number - 0.

Q2. What exactly does amensalism imply?

Ans: Amensalism is an ecological interaction between two species in which one gets eliminated or hampered while the other is unaffected. Amensalism is also a term used to characterise unequal competitive interaction.

Q3. What is the difference between commensalism and amensalism?

Ans: Commensalism is a relationship between two creatures in which one is always benefited but the other is neither benefited nor damaged, whereas amensalism is a relationship in which one is always injured but the other is neither harmed nor benefited.

Q4. Give an example of amensalism in the ocean?

Ans: Algal blooms have the potential to kill a lot of fish. On the other hand, the algae do not prosper from the extinction of those animals.

Q5. What role does amensalism play in the world?

Ans: Because it is a (0,-) interaction, amensalism is used in the management of a variety of harmful species. For example, consider the cases of Penicillium and Bacteria. Antibiotic production was boosted as a result of this. This interaction resulted in the development of penicillin, one of the most extensively used antibiotics in the world.