Herpetology – science olympiad student center wiki gas after eating pasta

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Hearts in all herps other than crocodiles consists of two atria and one ventricle somewhat divided by a septum. Contraction of heart keeps oxygenated and deoxygenated blood separate even though ventricle isn’t completely divided. In crocodiles, two atria and ventricles exist.

In reptiles, the cerebrum (used for controlling behavior) is larger than amphibians. Optic lobes are also large, due to the fact that many reptiles rely on sight for hunting. Some reptiles and amphibians have nictitating membrane which is a transparent,movable membrane that covers the eyes allowing them to see with their ‘eyelids’ closed.

Hearing is also important. Sound waves heat the tympanum and then are transferred to the inner ear through the columella. Snakes lack a tympanum and are effectively deaf. They are however able to sense vibrations caused by sound through a touch. They detect these ground vibrations which are transferred to columella by the bones of jaw.

The Jacobson’s organ is an extra sense organ in the roof of the mouth of reptiles. This organ is used to detect scents in the air. Reptiles use their forked tongue to gather chemicals from the environment and transfer it to the back of their mouth. These scent chemicals are then analyzed by the brain to find prey by using the two segments of the forked tongue independently gathering scent, and determining in the brain the direction of the scent through the sensitivity on each fork. While reptiles can smell with their nostrils, the jacobson organ is vastly more sensitive and important.

Many behavioral aspects of reptiles and amphibians are due to their thermoregulation strategies. Each of these species are ectotherms (cold-blooded and gaining heat from environment rather than metabolism). This energy saving strategy leads to several behavioral adaptations.

• Activity – Many ectotherms have optimum temperatures of function (due to the optimum temperatures of enzymes), this results in many organisms in cooler habitats being most active in midday and many organisms in desert habitats to be more nocturnal. The other pros and cons of diurnal/nocturnal are listed below.

Populations of various reptiles have diminished for several reasons. First of all is their (or their eggs) use as food in many cultures. (Snapping Turtle soup is actually quite tasty.) "Rattlesnake roundups" have occured in some states as recreational activities. Snakes are gathered to be killed by visitors who do so in belief that killing snakes protect public. Every year in Sweetwater, Texas, about 1% of the entire rattlesnake population of Texas is slaughtered. Some attendees claim that this is justified due to the fact that they collect venom, however the venom is useless for most any research as it is not collected in a sterile environment. Some are also gathered for use as folk medicine. Snake venom has use in medical research. Habitat destruction is also hurting various populations.

Amphibian populations have been mysteriously declining for several years. There are several proposed reasons for this decrease. Some believe thinning of the ozone layer increases the amount of UV B radiation that reaches sensitive eggs, embryos, and larvae causing them to die. Herbicides, pesticides, and fertilizers also have killed amphibians when interfering with their natural hormones. Habitat destruction and disease have also lead to a large amount of decrease in population.

One of the largest threats to anurans (frogs and toads) is a lethal fungal infection that has been expanding in prevalence and range in recent year. This disease, known as chrytridiomycosis, is caused by the chrytid fungus Batrachochytrium dendrobatidis. The disease is thought to increase in range with global warming. This disease is responsible for large numbers of frog death, and are among the leading causes of the extinction of several frog species, and possible more to come.

• International Union for Conservation of Nature and Natural Resources (IUCN): An international organization working in the field of nature conservation and sustainable use of natural resources composed of both government and civil society organizations

• Endangered Species Act of 1973 (ESA): Designed to enact provisions outlined in CITES, it was signed into law by Richard Nixon on December 28, 1973. It declares the categories E (endangered), T (threatened), C (candidate), ES/A (not endangered but similar in appearance to an endangered species), TS/A (not threatened but similar in appearance to a threatened species), XE (experimental essential), and XN (non-existential population)

• Committee on the Status of Endangered Wildlife in Canada (COSEWIC) or Comité sur la situation des espèces en péril au Canada (COSEPAC): An independent committee of wildlife experts and scientists that identifies species at risk in Canada: it designates X (extinct), XT (extirpated in Canada), E (endangered), T (threatened), SC (special concern), and NAR (not at risk).

Canada Wildlife Act: It specifies requirements for a geographic area in Canada to be designated a National Wildlife Area by the Canadian Wildlife Service division of Environment Canada. "The purpose of wildlife areas is to preserve habitats that are critical to migratory birds and other wildlife species, particularly those that are at risk." Further, the Wildlife Area Regulations, a component of the Canada Wildlife Act, identifies activities which are prohibited on such areas because they may harm a protected species or its habitat. In some circumstances, land use permits may be granted to individuals, organizations, or companies if the intended use is compatible with conservation of the area. Personal activities such as “hiking, canoeing, photography and bird watching can be carried out without a permit in most areas”.

• U.S. Fish and Wildlife Service (USFWS or FWS): Dedicated to the management of fish, wildlife, and natural habitats, it is an organization within the US Department of Interior. Its mission is "working with others to conserve, protect, and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people".

• Hibernation: Mechanism used by many mammals to reduce energy expenditure and survive food shortage over the winter, prepares by building up body fat, undergoes many physiological changes including decreased heart rate (by as much as 95%) and decreased body temperature

• Brumation: Reptiles generally begin brumation in late autumn (more specific times depend on the species). They often wake up to drink water and return to "sleep". They can go for months without food. Reptiles may eat more than usual before the brumation time but eat less or refuse food as the temperature drops. However, they do need to drink water. The brumation period is anywhere from one to eight months depending on the air temperature and the size, age, and health of the reptile. During the first year of life, many small reptiles do not fully brumate, but rather slow down and eat less often. Brumation is triggered by lack of heat and the decrease in the hours of daylight in winter, similar to hibernation. This differs from hibernation because the reptiles do not go into a sleeping state. Originally proposed by Mayhew (1965) “to indicate winter dormancy in ectothermic vertebrates that demonstrate physiological changes which are independent of body temperature.”

• Torpor: A state of decreased physiological activity, usually by a reduced body temperature and metabolic rate, some reptiles undergo this during short cooling periods, reptiles usually do not undergo this in the winter, mammals undergo this during hibernation

• Hermaphroditism: When a given individual in a species possesses both male and female reproductive organs or can alternate between possessing first one and then the other, usually sequential from female to male ( protogyny), less common for a male to switch to a female ( protandry)