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A couple of issues of interest to one or more other lovers:
- Are frogs hides?
- How good frogs can see?
- Can frogs smell and taste?
- How good frogs hear?
The organs of the frogs distinguished by many peculiarities, which this group unique among vertebrates do. By shortening the spine, an adjustment to the jumping, are the internal organs of frogs is concentrated in a relatively short and broad, almost droplet fuselage. Some species, like birds of the Neotropical glass frogs, possess a nearly transparent abdominal skin, an interesting insight into the abdominal cavity possible. A biological paradox occurs with some toads on: Eggs radical males. Male toads possess a stunted ovary, the so-called Biddersche body, which under normal circumstances by exposure to male sex hormones from the testes remain small and functionless. Only after removal of the inhibitory hormone by castration of the animals, the situation changed dramatically. From the Bidderschen organ develops in the course of 1-2 years, a functioning ovary, under the influence of female hormone is even a tubal forms - the male establishes eggs. Males with ovaries, under certain conditions can also occur in nature (eg, under the influence of herbicides), and the body is Biddersche as a textbook example of the fact that each animal in both sexes, the plants are dormant.
One of the main organs of the frogs is their skin. It fulfills a central function as breathing, water absorption, sensory and Exkretionsorgan. At regular intervals, a flaying the uppermost layer of keratin horn instead. The skin is the less spectacular than, for example, in snakes and in the rule is in shreds off skin immediately eaten. Die vielleicht wichtigste Aufgabe der Amphibienhaut besteht in der Atmung. Perhaps the most important task of the amphibian skin is to breathing. Die meist dünne und feuchte Oberfläche besitzt ein reich verzweigtes Kapillarnetz, das zwischen annähernd 100% (bei lungenlosen Salamandern) und 25% (bei manchen Kröten und Laubfröschen) der Atmung übernimmt. The usually thin and has a moist surface rich branched capillary, between the close to 100% (for respirable free salamanders) and 25% (in some toads and Laubfröschen) takes over the breathing. The African hair frog (Trichobatrachus robustus) has on the body sides and thighs strong flow, among amphibians unique "hair". This peculiar Hautauswüchse in the last century as "Wolllustorgane" were described, only the males for mating season. Presumably, the annexes provide an advantage when the oxygen Balz and brood, because basically most of the streams resident males can breath on her hair and must accomplish less likely to occur the water surface.
In contrast, the lungs are only a more or less folded, not very effectively working "air bag". In contrast to reptiles and mammals, with the help of chest movements breathe, contact the countless rip Anuren the simple, lung fish has practiced the principle of swallowing to breathing. A part of gas exchange (up 10%) for frogs of the strong circulation over oral mucosa. The latter two types of respiration are complementary and frogs can be between them "switch back and forth." The mouth breathing is slightly outwardly by the rapid raising and lowering of the throat region to recognize the lungs during breathing with significant swallowing movements. When tadpoles is also a fourth form of respiration, namely the gills breathing. The maximum of three pairs of gills are initially created externally, but - unlike in the larvae of Schwanzlurche - quickly from a tissue fold overgrown, so that a closed gill chamber with one or two gill openings created.
Most sense organs are well developed frogs. While many aquatic tadpoles and live Froschlurche, similar to the fish, even a sensitive lateral line system for recording of mechanical stimuli (water circulation), have guided terrestrial frogs, mainly through their eyes. The structure of the frog's eye corresponds to the general diagram of a vertebrate eye. In the retina, both rods are sitting as well as for the important color vision cone. Yet many seem Froschlurche colourblind to be, at least, their vision is limited to a few shades. The light receptors respond to different wavelengths than those of humans and some species are able to perceive UV light. Most Anuren register even very low light intensities, so that a visual orientation is possible even at night, but probably only in grayscale.
A prominent role in the Catching prey, the spatial vision and especially movements of frogs are very well perceived. The local and remote adjustment of the eye (accommodation) is however in a different way than other vertebrates. Since the lens in amphibians is not deformable, the setting is not on the curvature condition, but about a position change of the lens instead. The protection of sensitive eye area is protected by upper and lower eyelids ensured and additionally via a special transparent conjunctival fold, Nick the skin, as the "third eyelid" while also protecting jumping on the eyeball is withdrawn.
Also the sense of smell plays an important role in frogs. It consists of two distinct, separate systems, namely the original olfactory sense (smell different receptors) and in the tribal history of the first amphibians occurring in the mouth is, so-called Jacobsonschen body, the reptiles at his highest level of development achieved. For the assessment of prey are both olfactory systems of meaning and also the sense of taste, in the mouth and tongue region lying taste receptors. That probably smells even when the partner determination of frogs have a meaning, it was only recently recognized. In addition to the specific taste and smell is the sense centers of the entire skin of the Anuren interspersed with chemical receptors. Together with the likewise in the skin underlying touch, heat and pain receptors, they provide accurate information about the environment.
Amphibians can perceive airborne sound and the vast majority of frogs of the sense of hearing plays a predominant role for the innerartliche communication. This goes so far that many fewer species due to their appearance, but mainly to their different calls can be identified. Most frogs have a well-developed tympanic membrane for sound recording, and a middle that is the attraction of a special hearing bones (Columella) in the inner ear transmits. The inner ear, is not only a sensitive ear, but also the central institution for the balance, turning, and especially vibration sense. Frogs react is also very sensitive to vibrations of the substrate, an ability that are also in the innerartlichen communication is used and each researcher quickly becomes clear if one wanted, the ground frog calling for rapprochement silenced.
Source: National Museum of Natural History Stuttgart
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