Fishy Tales About Tetrapod Origins
It’s a stretch for mutation and selection to make a fish crawl out onto land with four digitized limbs, to say nothing of lungs and a new body plan.
Without doubt, the origin of four-footed vertebrates (tetrapods) is one of the “great transformations” Darwinists need to explain. The scope of the problem is described in the opening paragraph of Neil Shubin’s latest PNAS paper about his pet fish-a-pod, Tiktaalik (see 1/14/14) –
At first glance, the origin of tetrapods (limbed vertebrates) from finned precursors seems an almost insurmountable transition between life in water and life on land. If the basis of comparison were living taxa alone, then the anatomical and behavioral differences among finned and limbed vertebrates could appear vast: for example, fin structure and function differ dramatically from those of limbs.
A flurry of news articles appeared shortly after this paper was published, uncannily seeming to conspire to make the transition appear less daunting. Part of the conspiracy is hype, announcing small observations as if they have great importance. Another part is making flat-out assertions without evidential support. Here’s what some of them are saying:
- How did we get four limbs? Because we have a belly (Science Daily): “All of us backboned animals — at least the ones who also have jaws — have four fins or limbs, one pair in front and one pair behind. These have been modified dramatically in the course of evolution, into a marvelous variety of fins, legs, arms, flippers, and wings. But how did our earliest ancestors settle into such a consistent arrangement of two pairs of appendages? — Because we have a belly.”
- Spinal cord findings could help explain origins of limb control (Medical Xpress). “We might have more in common with a lamprey than we think, according to a new Northwestern University study on locomotion. At its core, the study of transparent zebrafish addresses a fundamental evolution issue: How did we get here?… Vertebrate locomotion has evolved from the simple left-right bending of the body exemplified by lampreys to the appearance of fins in bony fish to the movement of humans, with the complex nerve and muscle coordination necessary to move four limbs.”
- Evidence that land animals evolved the ability to breathe air as ancient fish (PhysOrg): “In a major evolutionary discovery, Flinders University palaeontologist Professor John Long (pictured) has found evidence to show that four-legged animals first developed the ability to breathe air as ancient fish in water…. the research shows the Polypterus, the most primitive living bony fish, breathes air through large canals on top of its head called spiracles.”
- Genetic clue to how limbs evolved from fins (BBC News): “The research in PloS Biology journal sheds light on how fish evolved into the earliest land animals millions of years ago. For fish to make the transition to land, an existing DNA architecture had to be ‘hijacked’ in order to make digits, the researchers said.”
- Conservation and Divergence of Regulatory Strategies at Hox Loci and the Origin of Tetrapod Digits (PLoS Biology): “The evolution of tetrapod limbs from fish fins enabled the conquest of land by vertebrates and thus represents a key step in evolution. Despite the use of comparative gene expression analyses, critical aspects of this transformation remain controversial, in particular the origin of digits…. We found … an evolutionary scenario whereby digits arose as tetrapod novelties through genetic retrofitting of preexisting regulatory landscapes.“
- A Footnote to the Evolution of Digits (Mary Hoff, PLoS Biology): “Half a billion years ago, the first four-legged land animal crawled out of the sea onto dry land. How did the limbs that creature crawled on evolve from the fins of its fishy ancestors? This question has long intrigued biologists…. the regulatory capacity to form digits was in place before land animals’ evolutionary emergence from the sea.”
- The evolution of lncRNA repertoires and expression patterns in tetrapods (Nature): “We compared expression patterns of homologous lncRNA and protein-coding families across tetrapods to reconstruct an evolutionarily conserved co-expression network.”
- How the genetic blueprints for limbs came from fish (Science Daily): “Our first four-legged land ancestor came out of the sea some 350 million years ago. Watching a lungfish, our closest living fish relative, crawl on its four pointed fins gives us an idea of what the first evolutionary steps on land probably looked like. However, the transitional path between fin structural elements in fish and limbs in tetrapods remains elusive.”
None of the articles ask, “Did” tetrapods evolve from fish; they somehow “know” that, and merely assume it. They ask, rather, “How” did tetrapods evolve from fish. Given that assumption, miracles of mutation and selection are possible, depending on the just-so storytelling ability of the writer.
Pathetic. This is snake oil salesmanship. Bits of bone or DNA are religious relics they hold up to the gullible, promising them life-changing miracles. Don’t buy the line! Keep jabbing them with the question: if your brain came from fish, how do you know anything, including the notion that your brain came from fish?
All the elements of fantasy fiction are seen in the above stories. Note especially the ideology-embedding phrases like evolutionary steps, transitional path, evolutionary emergence, evolutionary scenario, key step in evolution, digits arose as tetrapod novelties, sheds light on evolution, the course of evolution, has evolved, the evolution of this or that. Whenever needed, Darwin’s hidden hand provides the miracles: things emerge, arise, appear or develop on cue, even with the complex nerve and muscle coordination necessary to move four limbs. That is sick. That is not science. It is belief in natural miracles masquerading as knowledge, ignorance pretending to be wisdom. “How did we get four limbs? Because we have a belly.” Good grief. Your first job is to avoid brainwashing. Your second job is to help deprogram others.