Amensalism

Amensalism is a biological interaction between two species where one species is inhibited or harmed, and the other is neither benefited nor harmed. This contrasts with other interactions like mutualism, commensalism, and parasitism where at least one species experiences a clear positive impact. In amensalism, the affected species often experiences a reduction in population size, a decrease in resource availability, or direct physical harm. The 'amen' prefix signifies negation, highlighting the negative impact on one species, while the other remains indifferent. This interaction plays a crucial role in structuring ecological communities, impacting biodiversity and ecosystem dynamics. Competition, allelopathy, and resource deprivation are common mechanisms that drive this ecological relationship.

Amensalism meaning with examples

• A large walnut tree releases a chemical called juglone, which inhibits the growth of plants around it. The walnut tree thrives, unaffected by the presence of other plants, while these other plants suffer reduced growth and may even die due to the chemical's impact. This illustrates amensalism.
• Elephants trample vegetation as they move through the savanna. While the elephants aren't deriving any direct benefit from destroying the vegetation, their movements prevent the growth and survival of small plants and grasses. This demonstrates an example of how amensalism is realized.
• Barnacles attaching to a whale have no negative effect on the whale itself, as they do not harm the whales. Meanwhile, the barnacles can severely impede water flow for the feeding of organisms in the water that may also benefit from the water flow. This is an instance of amensalism.
• Certain species of seaweed in dense coastal environments block sunlight, which is detrimental to the growth of other, smaller species of algae and invertebrates living beneath them. The large seaweed does not directly benefit from this, and can be seen as an instance of amensalism.