Evolution is the process by which this occurs and it is spread out over many generations. Thus, the short minimal definition of biological evolution is, Evolution is a process that results in heritable changes in a population spread over many generations. This is a good working scientific definition of evolution; one that can be used to distinguish between evolution and similar changes that are not evolution.
Bone, cartilage, or dentine is used in the Ostracoderm fish and turtles. Chitin forms the exoskeleton in arthropods including insects, arachnids such as spiders, crustaceans such as crabs and lobsters (see arthropod exoskeleton), and in some fungi and bacteria. Calcium carbonates constitute the shells of molluscs (see Mollusc shell), brachiopods, and some tube-building polychaete worms.
Gabapentin is used primarily to treat seizures and neuropathic pain. It is also commonly prescribed for many off-label uses, such as treatment of anxiety disorders, insomnia, and bipolar disorder.There are, however, concerns regarding the quality of the trials conducted and evidence for some such uses, especially in the case of its use as a mood stabilizer in bipolar disorder.abapentin is not effective alone as a mood-stabilizing treatment for bipolar disorder. There is insufficient evidence to support its use in obsessive-compulsive disorder and treatment-resistant depression. Gabapentin does not appear effective for the treatment of tinnitus.