Preadaptation

Under preadaptation, Präadaption or predisposition ( synonyms for pre-adaptation ) is understood in both the evolutionary and developmental biology, the presence of either incidental or resulting from the original adaptive for a different purpose by mutation characteristics that with a change in environmental conditions prove to be a selective advantage. Make - to put it simply - an evolutionary adaptation before entering the selection pressure dar.

The evolutionary biologist Lorenzen explains the occurrence of this phenomenon this way: In many genotypes slumbering powers that be realized as in the cases listed only by adequate environmental stimuli. On the other hand, even minor genotypic changes under certain conditions can cause quite dramatic effects.

An obvious example of preadaptation are the wing membranes of frog Rhacophorus pardalis Borneo flight. They have webs between the toes and in the elbow joint. On the run, they can be covered by trees and sail to the ground. The wing membranes are homologous to the webbed other frogs. As these were already trained as an adaptation to life in the water, they represent a pre - adaptation to the gliding

A preadaptation may also be present because many of the features may have a double or multiple function. One example is the evolution of feathers and wings of birds. This had not necessarily run parallel coordinates. Springs were already present before the development of bird flight in dinosaurs and were used for thermal insulation. Recent fossil finds allow a series of intermediate stages from simple to complex design springs with unique ground-dwelling dinosaurs recognize. With the evolution of the wing they could then also serve the fly.

The preadaptation found by the discovery of alternative splicing and introns and exons, an additional molecular genetic basis. In particular, alternative splicing is a prime example of multi- function per se and made ​​possible by recombining already " proven " DNA code sections, a rapid development of new proteins without altering the primary DNA code. Taking into account that - as in humans - not encode directly more than 90 percent of the DNA for proteins, it is clear there is what amount of genetic information, which is actually activated for the emergence of new features already small changes in the DNA in the field of gene regulation. This particular feature of eukaryotes can be considered as a significant cause of the variety of forms these creatures group.