New Theory on Evolution of Bat Flight
How did bats evolve the ability to fly? Evolution helped them out by providing them with higher energy. After all, “Flight is among the most energy-consuming activities” in the animal kingdom, said a team of Chinese and Canadian scientists reporting in PNAS,1 so it’s obvious that evolution must have provided the genes to get the job done. So they looked at the genes of bats compared to other mammals, and sure enough, they found evidence of natural selection at work. “Both mitochondrial and nuclear-encoded OXPHOS [oxidative phosphorylation, a process of metabolism] genes display evidence of adaptive evolution along the common ancestral branch of bats, supporting our hypothesis that genes involved in energy metabolism were targets of natural selection and allowed adaptation to the huge change in energy demand that were required during the origin of flight.”
The team looked into the mitochondrial genes and nuclear genes of the two bats whose draft genomes have been published, and compared the genes for metabolism with several other mammals. They came up with statistics that indicated a 25% signature of “positive selection” in the mitochondrial genes and close to 5% for the nuclear genes (they claimed that “Positive selection and gene duplication are two major mechanisms of adaptive evolution”). They acknowledged, though, that identifying positive selection is tricky business:2
Typically, positive selection will act on only a few sites and for a short period of evolutionary time; thus the signal for positive selection usually is swamped by the continuous negative selection that occurs on most sites in a gene sequence. Even after a short period of positive selection, this is commonly followed by a long period of purifying selection, which would obscure the selective processes. These processes explain why it has been so difficult to detect positive selection in mtDNA, despite extensive studies.
Nevertheless, they defended several independent tests, such as branch-site models, to try to weed out and distinguish other signals, and thus support their identification of positive selection.
Now surely, they must realize there has to be more to it than that, right? Well, but of course. Their paper ends with this paragraph:
Bats are unique in being the only mammals capable of powered flapping flight. As in birds, bat flight is a highly energetically expensive form of locomotion. However, it is also a very efficient mode of transport and assists flyers in feeding and breeding as well as avoidance of predators. The evolution of flight in bats was a major factor leading to the success of this amazing group of mammals, although the evolution of this ability has required complex changes in the anatomy of these animals. In addition to other important factors, such as changes in bone density and development of the wings, bat flight also requires a significantly higher metabolic rate, a rate well above the maximum capable by other similar-sized terrestrial mammals during exercise. Aerobic metabolism by mitochondria plays a vital role as the energy production centers of cells The OXPHOS pathway of mitochondria has adaptively evolved to meet the demands of changing environmental and physiological conditions. Because the mitochondrial respiratory chain has a dual genetic foundation (mitochondria and nuclear genomes), here we examined both genomes to obtain insights into the evolution of flight by mammals. Both mitochondrial genes and nuclear-encoded OXPHOS genes showed greater evidence for adaptive evolution; this result supports our hypothesis that energy metabolism genes were targets of natural selection that included a balancing cytonuclear coevolutionary constraint, which allowed adaptive changes in energy demands and thus played a crucial role in attainment of flight by bats.
1. Yong-Yi Shen, Lu Liang, Zhou-Hai Zhu, Wei-Ping Zhou, David M. Irwin, and Ya-Ping Zhang, “Adaptive evolution of energy metabolism genes and the origin of flight in bats,” Proceedings of the National Academy of Sciences published online before print April 26, 2010, doi: 10.1073/pnas.0912613107.
2. For more on the pitfalls of measuring positive selection, or tying it to adaptive fitness, see 09/05/2008, 01/13/2010 bullet 6, and 02/17/2010 bullet 4.
We will have to call this the Mighty Mouse theory of bat evolution. It’s about as credible as the character who always managed to fly in for the rescue at the last moment (Wikipedia), and about as cartoony, too.
Papers like this are another reason we really, really need to end the one-party rule in science. The Darwin Party is so corrupt, its members have convinced themselves that this kind of research constitutes evidence for evolution. Undoubtedly, the leaders of the regime will stack this paper on top of their growing pile of propaganda to intimidate doubters by showing them the mounds of scientific evidence supporting Darwin’s theory. But this paper makes no sense at all unless one already is a member of the Darwin Party, has pledged allegiance to Darwin, and already vowed to interpret everything in the light of common descent by random mutations and natural selection. Then the reasoning is deductive: since we already know as axiomatic truth that bats evolved from rodents, then “this result supports our hypothesis that energy metabolism genes were targets of natural selection that included a balancing cytonuclear coevolutionary constraint, which allowed adaptive changes in energy demands and thus played a crucial role in attainment of flight by bats.”
The fogma is so thick they can’t see it. Only those outside of it can see what is going on. Simply put, adding energy to a mouse will not make it fly. Adding piecemeal goals to a Darwinian story will not make Darwinian theory fly, either. Darwinians need to think consistently with their theory. They cannot look in retrospect and say, Because bat flight evolved, this or that modification must have contributed to the overall complex trait. Bat flight is a package deal. As fossils have shown, bats appear abruptly in the record fully capable of flight and probably capable of sonar. More importantly, there is no “target of selection” in terms of an overall complex trait.
Think of a cow. What will it take to help Bessie evolve flight? Well, a high metabolism will surely be among the requirements. So let’s say that Tinker Bell comes along with her mutation wand and starts zapping poor Bessie in the gonads. Among the calves that don’t die as embryos, maybe there will be one some day that survives with a slightly higher metabolic rate. Are we getting warmer? Are we on the way to evolving flight in Bessie’s descendents? It’s not necessary to press the point to see how absurd this tale is already, and we haven’t even tried to talk Bessie into the advantages of how nice it will be for her descendents with wings some golden day, millions of years from now, to be able to efficiently escape their human predators that are trying to hunt them down for hamburger. (Don’t tell her that the human predators by then will have co-evolved into fearsome fighters flying at Mach 2.) Darwin’s theory demands that every beneficial mutation confer survival advantage right now, not millions of years in the future. It has no goals, no targets, no visions, no plans. A mouse in its hole has no desire to sprout wings and become a bat, no matter how nice it might be for feeding, breeding, and avoidance of predators.
Once again, we see how the Darwin supernaturalists conceal their miracles with misdirection and euphemisms. Everyone believes in miracles, you realize; and everyone is a supernaturalist. Darwinists only pretend to be naturalists. Their slip is showing every time they use logic and reason, which are not made of particles and forces. Look for the miracle-talk in this sentence: “The evolution of flight in bats was a major factor leading to the success of this amazing group of mammals, although the evolution of this ability has required complex changes in the anatomy of these animals.” OK, students, barrage the teacher with your questions. But teacher, how did this evolution occur? How can a Darwinian process be factored? – that sounds like algebra, a form of intelligent design. What do you mean by success – survival? The mice seemed to be pretty successful, because they still survive today and are more numerous than bats. How did the complex changes in the anatomy of bats occur simultaneously with the metabolic changes? How were they coordinated and tuned? You talked about changes in bone density and “the development of wings” – Wow! Isn’t that a giant leap for batkind? Didn’t Darwin say that nature takes no giant leaps, but only slight, successive modifications? What were the modifications, and how did they confer survival value? What do you mean by a “target” of natural selection? That sounds like anthropomorphism.
Who will ask these and other questions, if not creationists, the intelligent design movement, or at least critics of neo-Darwinism? Scientists need critics to keep them in line. When it comes to Darwinism, though, the whole regime is corrupt. Don’t look for critical thinking from the NAS, the NIH, NASA, the NSF, or the major secular journals. The news media aren’t holding them accountable, either (02/18/2010), except for independent sources like CEH. Many individual scientists have their heads on straight but those who try to buck the establishment risk marginalization or expulsion.
Totalitarian regimes typically become so corrupt that they become caricatures of themselves – fodder for political cartoons. That is certainly the case with the Darwin Party today. The rank and file largely ignore the ideology. They go along with it and repeat the party line on cue to stay out of trouble. No one dares speak out against it, even though an elementary course in baloney detecting could expose its nonsensical fables. The folly of theory-incestuous papers like this one shows that a thorough housecleaning is long overdue. Open the castle doors, DODO* bigots, and answer the challenge! Your mental health depends on lively and open debate. Listen to your founder: “A fair result can be obtained only by fully stating and balancing the facts and arguments on both sides of each question” – Charles Darwin.