In the framework of undirected evolution, organisms that reached the nearest peak of fitness find themselves in a "trap", and the achievement of a neighboring peak of fitness (even if it is much higher than the maximum on which they are located) is highly unlikely. Thus is the case of undirected evolution, it is not possible to offer a consistent mechanism of crossing ravines.
In the framework of directed evolution movement towards the highest set of fitness is just a part of this theory, in which the movement down the slope of adaptation is not prohibited and is not unlikely.
See, for example: Melkikh, A.V., Khrennikov, A. Molecular recognition of the environment and mechanisms of the origin of species in quantum-like modeling of evolution. Progress in Biophysics and Molecular Biology 2017. doi.org/10.1016/j.pbiomolbio.2017.04.008.
Article Molecular recognition of the environment and mechanisms of t...
In a static adaptive landscape, a deep valley or "canyon" essentially cannot be crossed, if it is wider than intraspecific variability. If it is very narrow, on the other hand, random mutation or recombination of genes could in principle allow its crossing by an individual "jumping across".
If the adaptive landscape is dynamic, a wandering adaptive peak at some point might cross the valley, carrying a species into new adaptive territory. See Savazzi, E. 2014: Adaptive landscapes and genetic algorithms. In: Cullum, A. & Martinius, A.W. (eds.): 52 things you should know about palaeontology: 24-25. Agile Libre, Nova Scotia. It is probably available for download on Researchgate.
I can think of several mechanisms that change the adaptive landscape in time. For example, a competitor species may disappear (either globally or from the geographic area inhabited by the species we are concerned with). This removes competition and allows our species to occupy the adaptive peak previously occupied by the competitor. We see this phenomenon on a massive scale in the recovery period after a mass extinction, for example.
Changes in the food resources may have comparable effects. So may climate changes.
In practice, in all these cases, our species does not actually cross the valley. A more correct way to describe this phenomenon is that the valley itself disappears, either temporarily or permanently.
What can species do if it has only chain of nucleotides? How to organize them in order to occupy the adaptive peak?
- Badges
- Science topic
- Similar topics
- Biological Science
- Bioecology
- Systems Ecology
- Landscape Ecology
- Connectivity