Title

Origins of electricity ?

Header/Pictures

Neurons may have evolved multiple times-placophora no neurons groups in the middle and may have lost genes
Intracellular communication-First receptors ( Burkhardt 2017)

For instance, if a nervous system means electrical impulses coupled to intercellular chemical signals, Liebeskind,2016
Around 600 Mya, after all five major lineages (ctenophores, sponges, placozoans, cnidarians, and bilaterians) had diverged, there was a sudden change. Large expansions of the gene families associated with synaptic and electrical complexity occurred together with profound changes on the biophysical level [34,38,57,58,60]. These changes occurred convergently in the stem lineages of ctenophores, cnidarians, and bilaterians (Figure 2). Although many of these genomic events cannot yet be dated precisely, they most likely followed the end of the worldwide glaciation events, contemporaneously with the rise of oceanic oxygen and macroscopic animal forms. The rise of inter-animal predation in the early Cambrian probably provided selective pressure to evolve complex behaviors, neural organization [67], and musculature [68]. It is perhaps not meaningful, therefore, to assign a single date to the origin of nervous systems, especially when one considers the genomic continuity between sensu stricto neurons and proto-neurons, and the large degree of homoplasy in animal nervous systems as a whole. Furthermore, the relatively late appearance of many aspects of nervous system complexity suggests that the precise branching order of the animal tree will not resolve the difficulties described above. Liebeskind,2016