Brains first make their appearance in the Cambrian explosion. Beware, your own brain may explode when you hear how Darwin defenders explain their origin.
Consider for a moment how complex even a simple brain is. A single neuron is very complex, lined with precision sodium channels that “fire” in sequence down an axon or dendrite. At the tip, vesicles carry complex chemical neurotransmitters across a gap, or synapse. But a single neuron is useless alone; it needs a network of other neurons to communicate information. That information must be processed by some kind of central nervous system, which must be able to interpret the information and respond by commanding other specialized tissues, such as muscles. The earliest Cambrian animals possessed brains that could operate numerous complex systems: sensory organs, digestive systems, articulated limbs, sexual organs and complex behaviors. Those things were lacking in their Precambrian predecessors, the Ediacarans.
Current Biology this month has a special section on the origin of brains. The authors commit the same blunders we saw just days ago: (1) they appeal only to unguided natural processes, (2) they rely on magic words, and (3) they ignore arguments and evidence for design of the type Stephen Meyer presents in Darwin’s Doubt. Brains just explode into existence — no intelligence required!
Name It and Claim It
In “The Basal Ganglia Over 500 Million Years,” in Current Biology, Grillner and Robertson have this to say:
Cyclostomes have evolved separately from mammals over more than 500 million years. It follows that when detailed similarities are demonstrated between forebrain circuits in the lampreys of today and those of mammals, these circuits were most likely already present at the dawn of vertebrate evolution (Figure 1). This was at the time of the Cambrian explosion when fossil records show the appearance of a multitude of now extinct species, but also the origin of different extant phyla like arthropods and molluscs, as well as vertebrates (cyclostomes). At this time, many of the molecular components of nerve cells had been designed (through evolution), including most ion channels, transmitters, and ionotropic and metabotropic receptors. [Emphasis added.]