Amensalismo and parasitism

Louse: a parasite well known

The amensalismo and parasitism are two ecological relationships that occur between different species (interspecific) and have in common the fact that, in both, a kind impairs the development of the other.

In amensalismo, inhibiting the development of a given population of individuals occurs without any favoring the causative species that frame. The destruction of plants and small living by large animals such as elephants, when walking, is an example. The release of toxins by dinoflagellates, the phenomenon of red tides, harming the beings that live in this habitat, is another example.

There is a particular type of amensalismo called antibiosis, which consists in inhibiting the development of individuals within a population due to excretion of substances with a part of another species. Penicillin, excreted by fungi of the genus Penicillium, was and still is widely used for the treatment of many bacterial infections, thanks to the accidental discovery of the relationship between such bodies, by Fleming in 1928.

Already parasitism is a relationship in which one organism (the parasite) is associated with another living being (the host) in order to feed themselves at your expense. When this occurs externally, either on the skin or the hair, we talk about ectoparasitismo. Now in a situation in which the parasite lives inside the body of the affected individual, such as bacteria and worms, it is endoparasitismo. Generally, the characteristics that do not confer advantages to the parasite are absent or atrophied; such as the digestive system and sense organs.

Parasites tend to cause weakness in the affected individual, but rarely cause death. Viruses, bacteria, protozoa and worms are the groups of living things best known in terms of parasitism. This relationship also exists between plants: vine-lead, for example, remove organic substances from other plants, to ensure their nutrition.

There are also two other forms of predation: the slavery in which individuals of a species to capture other distinct species, for these, as they grow, live as workers, seeking food for their parasites, and social parasitism in which certain animals make another species care for their young: a strategy widely used between cuckoos and other birds (their hosts).

By Mariana Araguaia
Graduated in Biology
Team Brazil School

Source: http://www.brasilescola.com/biologia/amensalismo-e-parasitismo.htm