(N/A) All animals, plants, and microbes in a biological community interact with each other.
- It is obvious that in nature, plants, animals, and microbes do not and cannot live in isolation but interact in various ways to form a biological community.
$\rightarrow$ Interspecific interactions arise from the interaction of populations of populations of two different species.
$\Rightarrow$ These interactions may be beneficial, detrimental, or neutral to one or both species.
The various outcomes are summarized in the table below:
| Species $A$ | Species $B$ | Name of Interaction |
| $+$ | $+$ | Mutualism |
| $-$ | $-$ | Competition |
| $+$ | $-$ | Predation |
| $+$ | $-$ | Parasitism |
| $+$ | $0$ | Commensalism |
| $-$ | $0$ | Amensalism |
$+$ sign indicates a beneficial interaction, $-$ sign indicates a detrimental interaction, and $0$ sign indicates a neutral interaction.
$\Rightarrow$ Both species benefit in mutualism, and both lose in competition.
In both parasitism and predation, only one species benefits (the parasite and predator, respectively), and the interaction is detrimental to the other species (the host and prey, respectively).
The interaction where one species is benefited and the other is neither benefited nor harmed is called commensalism. In amensalism, one species is harmed, whereas the other remains unaffected.