Volume Preface - Beck-Shop
... Fishes comprise the largest group of vertebrates by far. Indeed, there are more extant species of fishes than there are of all other vertebrate species combined. And, with this diversity in species, fishes show remarkable diversity and adaptations in the ways in which they deal with the aquatic envi ...
... Fishes comprise the largest group of vertebrates by far. Indeed, there are more extant species of fishes than there are of all other vertebrate species combined. And, with this diversity in species, fishes show remarkable diversity and adaptations in the ways in which they deal with the aquatic envi ...
Passive electrolocation in fish
Passive Electrolocation is a process where certain species of fish or aquatic amphibians can detect electric fields using specialized electroreceptors to detect and to locate the source of an external electric field in its environment creating the electric field. These external electric fields can be produced from animate sources such as:DC fields produced by any bioelectrical process in a living organismDC fields produced from wounded or damaged organismElectric fields produced by actions of the nerves or muscles of fishElectric fields emitted by specially developed electric organs from fishor to inanimate sources such as the electric fields induced by movement of a conducting organism through the earth's magnetic field, or from atmospheric electricity These external fields the fish identifies are low or high frequency, weak electric signals that the fish uses to detect prey, locate other fish, avoid predators, and navigate in the Earth’s magnetic field. Electrorectors probably evolved once or twice in early in vertebrate evolution but the sense was apparently lost in animiotes, and in a large number of the actinopterygians (ray finned fishes) only to reappear independently in two teleost clades. In fish, the ampullary receptor is a specialized receptor that it uses to sense these electric fields and allows the fish to follow electric field lines to their source. Sharks primarily use specialized receptors, called Ampullae of Lorenzini, to detect prey’s low frequency DC fields and may also use their receptors in navigation of the Earth’s magnetic field. Weakly electric fish use their ampullary receptors and tuberous receptors to detect the weakly electric fields produced by other fish, as well as for possible predator avoidance. Passive electrolocation contrasts with active electrolocation, in which the animal emits its own weak self generated electric field and detects nearby objects by detecting the distortion of its produced electric field. In active electrolocation the animal senses its own electromotor discharge or reafference instead of some externally generated electric field or discharge