Categories
There are two basic categories of facilitative interactions:
- A mutualism is an interaction between species that is beneficial to both. A familiar example of a mutualism is the relationship between flowering plants and their pollinators. The plant benefits from the spread of pollen between flowers, while the pollinator receives some form of nourishment, either from nectar or the pollen itself.
- A commensalism is an interaction in which one species benefits and the other species is unaffected. Epiphytes (plants growing on other plants, usually trees) have a commensal relationship with their host plant because the epiphyte benefits in some way (e.g., by escaping competition with terrestrial plants or by gaining greater access to sunlight) while the host plant is apparently unaffected.
Strict categorization, however, is not possible for some complex species interactions. For example, seed germination and survival in harsh environments is often higher under so-called nurse plants than on open ground. A nurse plant is one with an established canopy, beneath which germination and survival are more likely due to increased shade, soil moisture, and nutrients. Thus, the relationship between seedlings and their nurse plants is commensal. However, as the seedlings grow into established plants, they are likely to compete with their former benefactors for resources.
Read more about this topic: Ecological Facilitation
Famous quotes containing the word categories:
“The analogy between the mind and a computer fails for many reasons. The brain is constructed by principles that assure diversity and degeneracy. Unlike a computer, it has no replicative memory. It is historical and value driven. It forms categories by internal criteria and by constraints acting at many scales, not by means of a syntactically constructed program. The world with which the brain interacts is not unequivocally made up of classical categories.”
—Gerald M. Edelman (b. 1928)
“Kitsch ... is one of the major categories of the modern object. Knick-knacks, rustic odds-and-ends, souvenirs, lampshades, and African masks: the kitsch-object is collectively this whole plethora of “trashy,” sham or faked objects, this whole museum of junk which proliferates everywhere.... Kitsch is the equivalent to the “cliché” in discourse.”
—Jean Baudrillard (b. 1929)
“Of course I’m a black writer.... I’m not just a black writer, but categories like black writer, woman writer and Latin American writer aren’t marginal anymore. We have to acknowledge that the thing we call “literature” is more pluralistic now, just as society ought to be. The melting pot never worked. We ought to be able to accept on equal terms everybody from the Hassidim to Walter Lippmann, from the Rastafarians to Ralph Bunche.”
—Toni Morrison (b. 1931)