Buranyi starts off with a clear and concise summary of the development of the modern Neo-Darwinian synthesis in the first half of the 20th century, culminating in the centenary in 1959 of the publication of Darwin's Origin of Species.
He follows this history with a description of how developments in molecular biology in the 1960s began to undermine that synthesis, particularly the discovery that natural selection did not play the crucial role it had been thought to play.
As one scientist put it:
The genes were changing – that is, evolving – but natural selection wasn’t playing a part. Some genetic changes were being preserved for no reason apart from pure chance. Natural selection seemed to be asleep at the wheel.This realization threatened to undo the modern theory. If natural selection wasn't the driving force of evolutionary change what was?
Evolutionary biologists were stunned. In 1973, David Attenborough presented a BBC documentary that included an interview with one of the leading modern synthesists, Theodosius Dobzhansky.Today the unity and optimism of 1959 has dissipated and biologists have become a fractious lot. One of the many findings that have thrown the discipline into turmoil is the discovery of the amazing phenomenon called plasticity.
He was visibly distraught at the “non-Darwinian evolution” that some scientists were now proposing. “If this were so, evolution would have hardly any meaning, and would not be going anywhere in particular,” he said. “This is not simply a quibble among specialists. To a man looking for the meaning of his existence, evolution by natural selection makes sense.”
Where once Christians had complained that Darwin’s theory made life meaningless, now Darwinists levelled the same complaint at scientists who contradicted Darwin.....
Other assaults on evolutionary orthodoxy followed....
Perhaps the biggest change from the theory’s mid-century glory days is that its most ambitious claims – that simply by understanding genes and natural selection, we can understand all life on earth – have been dropped, or now come weighted with caveats and exceptions. This shift has occurred with little fanfare.
The theory’s ideas are still deeply embedded in the field, yet no formal reckoning with its failures or schisms has occurred.
To its critics, the modern synthesis occupies a position akin to a president reneging on a campaign promise – it failed to satisfy its entire coalition, but remains in office, hands on the levers of power, despite its diminished offer.
This is the ability of some organisms to develop new or modified anatomical structures more rapidly than Darwinian gradualism allows:
Descriptions of plasticity are startling, bringing to mind the kinds of wild transformations you might expect to find in comic books and science fiction movies.
Emily Standen is a scientist at the University of Ottawa, who studies Polypterus senegalus, AKA the Senegal bichir, a fish that not only has gills but also primitive lungs. Regular polypterus can breathe air at the surface, but they are “much more content” living underwater, she says.
But when Standen took Polypterus that had spent their first few weeks of life in water, and subsequently raised them on land, their bodies began to change immediately. The bones in their fins elongated and became sharper, able to pull them along dry land with the help of wider joint sockets and larger muscles.
Their necks softened. Their primordial lungs expanded and their other organs shifted to accommodate them.
Their entire appearance transformed. “They resembled the transition species you see in the fossil record, partway between sea and land,” Standen told me. According to the traditional theory of evolution, this kind of change takes millions of years. But, says Armin Moczek, an extended synthesis proponent, the Senegal bichir “is adapting to land in a single generation”.
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| Senegal bichir |
The point, though Buranyi doesn't explicitly state it, is that naturalistic evolution is a theory that seems to be suffering the erosion of the most crucial element of any scientific theory - explanatory power. As scientific discovery continues apace the ability to explain what's being discovered in naturalistic terms seems to be diminishing.
These words serve as a suitable conclusion to the essay although they come early on:
Everyone agrees that natural selection plays a role, as does mutation and random chance. But how exactly these processes interact – and whether other forces might also be at work – has become the subject of bitter dispute.Perhaps the day is coming when among "other forces that may be at work" biologists will seriously consider an intelligent mind.
“If we cannot explain things with the tools we have right now,” the Yale University biologist Günter Wagner told me, “we must find new ways of explaining.”
