Physics · Evolutionary Biology and Neuroscience

Arrange the following sentences in a logical order to form a coherent paragraph: 1. Complex computational elements of the CNS are organized according to a 'nested' hierarchic criterion; the organization is not permanent and can change dynamically from moment to moment as they carry out a computational task. 2. Echolocation in bats exemplifies adaptation produced by natural selection; a function not produced by natural selection for its current use is exaptation -- feathers might have originally arisen in the context of selection for insulation. 3. From a structural standpoint, consistent with exaptation, the living organism is organized as a complex of 'Russian Matryoshka Dolls' -- smaller structures are contained within larger ones in multiple layers. 4. The exaptation concept, and the Russian-doll organization concept of living beings deduced from studies on evolution of the various apparatuses in mammals, can be applied for the most complex human organ: the central nervous system (CNS).