Pick the correct option regarding to the population interaction that could be beneficial, detrimental or neutral (neither harm nor benefit) to one of the species or both. Assigning a ‘+’ sign for beneficial interaction, ‘-’ sign for detrimental and 0 for neutral interaction:

Name of interaction      species A         Species B

Amensalism                         -                       0

The correct answer is Option (1) -

Name of interaction      species A         Species B

Amensalism                         -                       0

In amensalism on the other hand one species is harmed whereas the other is unaffected. Predation, parasitism and commensalism share a common characteristic– the interacting species live closely together.

Mutualism: This interaction confers benefits on both the interacting species. Lichens represent an intimate mutualistic relationship between a fungus and photosynthesising algae or cyanobacteria. Similarly, the mycorrhizae are associations between fungi and the roots of higher plants. The fungi help the plant in the absorption of essential nutrients from the soil while the plant in turn provides the fungi with energy-yielding carbohydrates.

Competition is best defined as a process in which the fitness of one species (measured in terms of its ‘r’ the intrinsic rate of increase) is significantly lower in the presence of another species. The Abingdon tortoise in Galapagos Islands became extinct within a decade after goats were introduced on the island, apparently due to the greater browsing efficiency of the goats. Balanus and Chthamalus are both types of barnacles that compete for space and resources in the intertidal zone, which is an example of competition.

Predation is the interaction between prey and a predator, where the energy flows from one organism to the other. The predator is the organism that feeds on other organisms called prey.

let us look at all the possible outcomes of interspecific interactions.

Species A          Species B          Name of Interaction

     +                       +                  Mutualism

     –                        –                  Competition

     +                        –                 Predation

     +                        –                 Parasitism

     +                        0                 Commensalism

     –                        0                 Amensalism