User:Slake7

Wikipedia article selections
The first article that needs reviewing is Infrared sensing in snakes. The page lacks information pertaining to the molecular mechanisms underlying thermal vision and the addition of this information will greatly improve the understanding of how infrared wavelengths are transformed into an image in boas, pit vipers and pythons.

The second article that needs reviewing is Thermoception. This page has a very poor explanation of thermal vision in snakes; it is missing a great deal of information and is in need of more citations. Reviewing this article will improve the interspecific comparisons being made in this article.

The third article that needs reviewing is Pit viper. Pit vipers have thermal vision that is more sensitive than boas or pythons, and the physiology that allows for the high sensitivity is not reviewed in this article. The addition of this information will allow for a better comparison among the snake families, and reinforce where Crotalinae snakes get the name pit viper from.

Article to review: Infrared sensing in snakes
There is no explanation of the molecular mechanisms underlying the adaptive evolution of thermal vision in snakes, and adding this information will validate with genetic evidence that thermal vision evolved independently among boas, pythons and pit vipers. Secondly, the physiological and anatomical differences among boas, pythons and pit vipers are discussed on this page but there is no behavioral evidence that there is a varying response to infrared stimuli. Adding behavioral evidence will further support that pit vipers are more sensitive to infrared radiation than boas and pythons. Finally, there is also discussion on the page that the pit organ adapts to a thermal stimulus, but does not outline that this occurs through heat exchange.

Geng et al., 2011
Geng  et al.  (2011) sequenced the gene for the infrared receptor (TRPA1) and its closely related gene (TRPV1) in 24 species of snakes and constructed phylogenetic trees at the DNA and protein level.


 * The TRPA1 branches were longer than TRPV1 branches in the three snake families that have thermal vision (Boidae, Pythonidae and Viperidae). There was no difference in branch lengths between TRPA1 and TRPV1 in snake families that lack thermal vision, indicating TRPA1 evolved rapidly in boas, pythons and pit vipers
 * TRPA1 was under positive selective pressure, but only in snake families with pit organs
 * The study confirms that TRPA1 underwent convergent evolution, and acquired an additional, or enhanced function as an infrared receptor in boas, pythons and pit vipers

Ebert et al., 2007
The study by Ebert et al. (2007) was the first study to behaviorally determine the maximum distance of infrared detection in blindfolded ball pythons,  Python regius 


 * Without visual cues, the blindfolded pythons had an infrared detection threshold of 30 cm, beyond which thermal contrast was minimal and no behavioral responses were elicited
 * Pythons behaviorally responded to one third of thermal stimuli within their detection threshold
 * This study allowed for the behavioral comparison of pythons to rattlesnakes, which were used in their previous study . Ebert et al. (2007) concluded that pythons have a much lower infrared detection threshold and are less likely to elicit a response to thermal stimuli compared to rattlesnakes.

Goris et al., 2000
The study by Goris  et al.  (2000) provided evidence for the hypothesis that heat exchange maintains the pit organ membrane at a constant temperature. This also provides physiological evidence for the discussion point in the article that the pit organ adapts to a thermal stimulus.


 * Terminal nerve masses that innervate the pit organ control blood flow within the pit membrane
 * When the pit receptors are activated by infrared radiation, blood flow increases and the rate of heat exchange in the capillary bed increases.
 * Heat exchange returns the temperature of the receptors to a basal temperature, which allows the receptors to continuously respond to a succession of thermal stimuli