Saturday, January 15, 2011

Toddler Stomach Anatomy Diagram

loquat and curry Monopolies, organic markets and exchanges

The exchange of social benefits is not unique to humans. In the animal world-there are numerous species, a multitude of opportunities for social interaction, as in the case of cooperation. Several models have been developed on purpose, and new ways of approaching the subject are implemented by behavioral ecologists around the world.
Even some economic theories permeate (successfully) in biology, as in the case of the theory of biological markets . According to this theory, the cooperative acts are "goods" that can be exchanged in accordance with supply and demand exerted by the participating classes.
Some studies have explored this proposal and found "simple and elegant shapes, which seem to be biological markets in the animal world. For example, an organic market related to reproductive males and females represent the classes involved. In those species where there is internal fertilization, females would be disadvantaged class. That is, the cost of a copulation-by the subsequent pregnancy-would be greater for them both in resources and time. So, given that females would be gamete possessing valuable could also be the extra benefits they could gain access in exchange for sexual favors.
class What is the advantage and disadvantage in which an exchange is important in the context of biological markets. The asymmetry between the classes can determine the form of trade.
In interactions where there is some asymmetry, for example, between fish cleaners and their clients - the victims may be less vulnerable to exploitation when they have the right to terminate the interaction. Consequently, the operator would more careful and should try not to overdo, since the victim would be able not only to limit the operation but also to eliminate the possibility of future cooperative interactions. But at a disadvantage if the class had no control over the termination of interactions would be another story.
The grooming (grooming ) in primates can be considered as a commodity for hygienic and hedonistic benefits it provides to those who receive it. In a study with chacma baboons (Papio hamadryas ursinus ) found that individuals can exchange reciprocal grooming or to gain access to other goods and the handling of small pups . The time that mothers were groomed varied depending on the number of offspring available. That is, other group members were willing to "pay" more grooming when pups were scarce.
Recently, Parry Clarke, Jo Halliday, Louise Barrett and Peter Henzi wondered whether biological market theory could also explain the sexual intercourse between male and female baboon chacma and if, in this case, the grooming also functioned as a commodity. To answer this used a lot of data obtained in the field and various mathematical models, their results were published in late 2010 in the journal Behavioral Ecology .
In several species males have been found to exchange certain goods or resources to access the sexual favors of females. For example, chimpanzees exchanged food for copulations. Accordingly one might expect that such exchanges respond to, for example, the number of sexually receptive females one time and the number of males to compete for them.
However, males may not be interested in sharing profits with the females if they could appropriate the resources in contention (sexual benefits) by force. In other words, sexual coercion may be a strategy that would eliminate the need for cooperative exchanges. This could occur in those species, such as chacma baboons, where males are much larger than females and, therefore, may coerce more successfully.
chacma baboon male with injuries resulting from a fight with another male. Stock Guillermina Echeverria-Lozano.
However, females could promote competition between males and thus get around the problem of coercion, even to prevent it. But in species where males hierarchical position determines access to receptive females then exchanges related to mating between males and females were virtually nonexistent. This in mind is that Parry's team conducted an analysis of the sex trade in chacma baboons.
They used various mathematical models that take into account data on grooming between males and females, the hierarchy of males present at the troops, the number of females compared to males, copulations and characteristics , proximity between males and females during different periods of receptivity and fertility of females, among others.
Their results suggest that in the proposed framework, the theory of biological markets not adequately explain exchanges between males and females. This is because males do not groom the females and half the time they do receive unsolicited grooming more frequently than they are, how much grooming they provide is not related to the number of matings they obtain, but if it is related to the amount of grooming they provide. Ie, grooming seems to be reversed.
Females do not appear to be using grooming as a commodity exchange, or at least do not seem to be doing on their behalf in the manner originally proposed. Furthermore, the level of competition (aggression) between males for access to females was too low to be considered of importance.
Parry and his colleagues propose that echelons are males and the subsequent elimination of competitors that mediates sexual interactions in this type of terrestrial primates. That is, in a market where the monopoly is possible and competitors can be eliminated then the law of supply and demand can not be applied, at least not in the terms in which the biological markets theory suggests. Consequently, the resistance of females to males would be pointless and, indeed, could be very costly for them.
For chacma baboons, it is interesting that the females are the main groomers during exchanges with male grooming and it is associated with the probability of a copula.
Parry and his colleagues also proposed that when females have no other option than to accept the dominant male copulations they could then take the opportunity to attempt to obtain additional benefits of females (a limpiadita extra coat did not dislike anyone) and would explain the fact that the females are the main groomers during courtship. The exchange between males and females then occur under control that males have over females.
Parry and his team conclude by stressing the idea that to properly understand sexual selection is important to consider how the individual components of it (such as intrasexual competition, mate choice and sexual coercion) interact and feed each other.
Perhaps the most complex economic models have to be employed to explain more fully the interactions and social exchanges observed in the animal world.
intersexual aggression in chacma baboons. Stock Peter Henzi.

Reference article:




ResearchBlogging.org

Clarke, P., Halliday, J., Barrett, L., & Henzi, S. (2010). Chacma baboon mating Markets: Potential competitor suppression mediates the exchange intersexual for Behavioral Ecology, 21 (6), 1211-1220 DOI: 10.1093/beheco/arq125
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