For Complex Life, Just Add Oxygen

first_imgWhen you take in a breath of fresh air, you let in a lively but dangerous molecule that would kill you if it were not that your cells have elaborate controls to utilize its energy for good and avoid its damaging potential.  Oxygen makes forests burn to ashes but also powers your muscles.  Astrobiologists realize that oxygen would have ruled out the origin of life if present on the alleged primitive earth, but now some think that, once life started, oxygen paved the road to pines and peacocks.    EurekAlert sums up a presentation published in BioMed Central Evolutionary Biology with the announcement, “Oxygen triggered the evolution of advanced life forms.”  S. Blair Hedges (Penn State), one of the authors, explained: “To build a complex multicellular organism, with all the communication and signalling between cells it entails, you need energy.  With no oxygen or mitochondria, complex organisms couldn’t get enough of this energy to develop.”  His team performed a statistical analysis of the amount of complexity of life forms assumed through evolutionary time.  They admit up front that “the pattern and timing of the rise in complex multicellular life during Earth’s history has not been established.”  In fact, there is a large and serious disconnect in the data sets: “Great disparity persists between the pattern suggested by the fossil record and that estimated by molecular clocks, especially for plants, animals, fungi, and the deepest branches of the eukaryote tree.”  Nevertheless, they pulled together a large set of protein sequence data and applied molecular clock assumptions to it “to place constraints on the increase in complexity through time.”    They attempted to derive branching times on the tree of life, and counted the diversity of cell types for each group.  They noticed an apparent acceleration in the variety of cell types that seemed to be associated with the initial increase in oxygen levels about 2.3 billion years ago.  “The results suggest that oxygen levels in the environment, and the ability of eukaryotes to extract energy from oxygen, as well as produce oxygen, were key factors in the rise of complex multicellular life.  Mitochondria and organisms with more than 2-3 cell types appeared soon after the initial increase in oxygen levels at 2300 Ma [2300 million years ago].  The addition of plastids at 1500 Ma, allowing eukaryotes to produce oxygen, preceded the major rise in complexity.”  What this means, they believe, is that oxygen triggered the rise of complex life.1Hedges et al., “A molecular timescale of eukaryote evolution and the rise of complex multicellular life,” BioMed Central Evolutionary Biology, 2004, 4:2 (published 28 January 2004).This is like correlating the stock market to the sunspot cycle, or worse, to a random number generator.  It’s a circumstantial argument based on begging the question whether evolution is even true.  They admit that the fossil evidence, which should be considered more reliable, flatly contradicts the molecular evidence, which others have already lamented is a broken clock.  Why do mythmakers masquerading as scientists get away with this bogus reasoning?  Why do science news outlet depict their mythical hypotheses as conclusions?  Maybe the solution will come, as with network news, when ratings keep dropping.  At a certain point it won’t matter what lies they tell, because no one will be listening.(Visited 9 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img