In contrast, the hypothesis of concerted brain evolution assumes that as the regions of the brain are physiologically and developmentally interconnected, any evolutionary change (or a new acquisition) in the brain cannot advance without involving all parts of the brain, thereby leading to a coordinated variation in size ( Finlay and Darlington, 1995). The hypothesis of mosaic brain evolution relies on the selective forces acting on specific areas of the brain, whose adaptive responses do not involve other parts of the brain ( Barton and Harvey, 2000). Presently, there are two theories attempting to explain the evolutionary patterns observed in the brain of vertebrates. However, the evolutionary mechanisms underlying these functional links are unknown. The variation in the size and composition of the brain often correlates with diverse sensory, behavioral, social, and cognitive skills ( Butler and Hodos, 2005). What we do know well is that although all vertebrates share a common basic brain organization, different species exhibit wide variability in terms of volumes and proportional sizes of different subdivisions and neural systems. Certain limitations arise from the fact that we are using an organ in order to explain itself and moreover the brain is not complex enough to understand its own complexity. The brain is the most complicated organ, due to which many of its functional and evolutionary processes still remain obscure despite the availability of a vast array of studies.

Fish brain app silent