Celebrating Darwinism we see another story, this time about the nervous system. When it comes to historical science, there is much imagination involved, because nobody can go back into time to observe the past.
So what did Greg Miller believed the first neurons and nervous systems looked like, and what advantages were there? He begins his explanation…
“The nervous systems of modern animals are amazingly diverse. A few hundred nerve cells are all a lowly nematode needs to find food and a mate. With about 100,000 neurons, a fruit fly can perform aerial acrobatics, dance to woo a mate, and throw kicks and punches to repel a rival.”
“The sperm whale’s 8-kilogram brain, the largest on the planet, is the navigation system for cross-ocean travel and 1000-meter dives and enables these highly social creatures to communicate. The human brain—one-sixth that size—is the wellspring of art, literature, and scientific inquiry.”
Good science here, the study of the nervous system without the evolutionary explanation, that was the easy part, it’s observable. It didn’t however answer the origin of the nervous system and what it looked like, but let’s give him time. This is going to be a tough one…
“Using such modern tools, scientists have recently begun to gain some tantalizing clues about the evolutionary origins of nervous systems. They’ve found that some of the key molecular building blocks of neurons predate even the first multicellular organisms.”
“By looking down the tree of life, they are concluding that assembling these components into a cell a modern neuroscientist would recognize as a neuron probably happened very early in animal evolution, more than 600 million years ago. Most scientists agree that circuits of interconnected neurons probably arose soon thereafter, first as diffuse webs and later as a centralized brain and nerves.”
“But the resolution of this picture is fuzzy. The order in which early branches split off the animal tree of life is controversial, and different arrangements imply different story lines for the origins and early evolution of nervous systems. The phylogeny is “a bit of a rat’s nest right now,” says Sally Leys of the University of Alberta in Edmonton, Canada.”
“Scientists also disagree on which animals were the first to have a centralized nervous system and how many times neurons and nervous systems evolved independently. Peering back through the ages for a glimpse of the first nervous systems is no easy trick.”
So we hear of these “tantalizing clues” and these “story lines” with low-resolution pictures which are not helping followed by the suggestion that this very complex system arose several times independently. It doesn’t appear Greg Miller has any answer in sight! But does try and soften up the audience with the radical idea of multiple independent origins. I wonder what the odds are of trying to duplicate not one but several independent origins.
It gets better, he moves on to the next subject, “How to Build a Neuron.” Like before, he starts out with empirical facts about about the subject matter, then moves off to the evolutionary part which is where the imagination begins…
“Arranged in circuits, neurons open up new behavioral possibilities for an animal. Electrical conduction via axons is faster and more precise than the diffusion of chemical signals, enabling quick detection and a coordinated response to threats and opportunities. With a few upgrades, a nervous system can remember past experiences and anticipate the future.”
Miller invokes the power of convergent evolution: “Neurons may have appeared in multiple lineages in a relatively short time.” There appears to be a need for factual support to back up this claim, so Miller appeals to Paramecium and other single-celled organisms that can respond with a cascade of signals when they touch an obstacle.
This time, the Multi-Universe theory type explanation is invoked…Explain fine tuning with more fine tuning, or in this case Miller appeals to one complex system to explain the origin of another complex system. What seems obviously absent from this story is, he did not described any of this in terms of mutations and natural selection.
He then moves on with a transitional link namely the sponge, but fails to explain why would natural selection build a complex system on a animal that doesn’t need it or have any use for it. What a predicament Miller’s explanation has become. Besides the empirical part, the rest he suggested was all fiction, imagination, speculation, futureware and miracles, with specified complex systems just emerging out of nowhere, giving rise to and appearing left and right without links, causes or evidence.