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Controversy over Thermal Vents Heating Up: A recent BBC news article, "Row erupts over 'life-starter' vents ," thermal vents, thought by some to be ancient sources of underwater heat that might have spawned the origin of life billions of years ago, may really be "nothing more than deposits from underground springs active in the last few thousand years." The article notes that "Seafloor hydrothermal vents emit jets of mineral-rich water that has been superheated to up to 400 Celsius by submarine volcanoes." If these vents are very young, then "[t]his is one chink in the armour of models depicting the early Earth as one big hydrothermal system" implying that hydrothermal vents may not have played an important role in the formation of life. As noted previously, the "Vent Hypothesis" has other problems, such a the extreme temperatures that would break down pre-biotic monomers and the fact that some important steps in the origin of life could not take place in an aqueous solution (i.e. polymerization cannot occur in water).
Could Life Form from Clay? A CNN news article, Study suggests life sprang from clay," claims to have found a way to create clay vesicles that allow molecules to enter inside of them, forming a possible pathway to the first primitive cell-walls that encapsulated early "RNA-world" life. Assuming such life existed, one must ask how the molecule-sized life survived before it found the clay (and what are the odds of such a finding taking place), and then how it learned to regulate transport of good substances into the "clay vesicle" and harmful substances out. Modern cells use highly specific glycoproteins, encoded by DNA, produced in a ribosome, and then embedded in to the cell wall to recognize friendly substances and invite them in, and keep bad substances out. Though this clay study seems to have found a way to get stuff in--that doesn't help matters because one must not let just anything in, but only those molecules wihch are helpful to the lifeform within. Since the clay vesicle is not encoded, there is no way to regulate its grow or determine the nature of the clay vesicle. The researchers also claim to have, "demonstrated growth and division without any biochemical machinery." This is nothing new as a "budding" form of growth was demonstrated in the "soap bubble-like" growth-by-budding proteinoid microspheres of Sidney Fox. If these clay vesicles are anything like that, then the growth is not biologically controlled-it's just a matter of splitting a bubble in two. Oh yeah, one last note: cell walls are not made out of clay--how did the clay --> lipid transition take place? (10/25/03)
Could Life Form in a Vent? The "Vent Hypothesis" where life formed in a deep sea thermal vent was reiterated in a NY Times science article entitled "Deep Under the Sea, Boiling Founts of Life Itself." The authors speculated that the first forms of life may have been microbes that lived in the deep waters of the ocean and "breathed iron." This hypothesis is highly speculative, it ignores that 1) high heat would degrade pre-biotic organic molecules very quickly (which is why some proposed a "cold" origins of life!) and 2) the origins of life could not happen in water because polymerization requires dehydration synthesis. See Problems with the Chemical Origins of Life for details. (9/9/03)
Gerald Joyce and Jeffery Bada Lecture at UCSD on the Origins of Life: At recent talks given by Drs. Gerald Joyce at UCSD in honor of the 50th anniversary of the publication of the "Miller-Urey" experiments, Dr. Joyce discussed with openness the strengths and weaknesses of the RNA World hypothesis and Dr. Bada discussed strengths and weaknesses of Dr. Miller's experiments in creating a prebiotic soup. Miller's experiments apparently didn't use the gasses present on the early earth, and it is unlikely that pre-biotic organic material came to earth from space. According to Bada, prebiotic synthesis occured in "localized synthesis" where he gave no mechanism for ovrecoming the presence improper gasses in the atmosphere. The RNA world is purely hypothetical, assumes a naturalistic past where some intermediate stage between the first life and DNA is needed, and under that assumption is based upon the observation that cells today use RNA in many different ways. Though many interesting biochemical molecules have been designed in the lab to be based off of RNA, a metabolic system of RNA has never been created, nor is it known how it could have evolved from pre-RNA precursors nor turned into DNA through Darwinian processes. Please click here for a report..(6/10/03)
Bacteria and Meteorites: "University of Dayton Geologist recreates "Life On Mars' Evidence in her laboratory" (click here to see the report in "Lunar and Planetary Science, "A Non-Biological Origin for the Nanophase Magnetite Grains in ALH001: Experimental Results") In 1996, NASA scientists reported having discovered grains of the mineral magnetite in a meteorite, which look very similar to magnetite grains produced by bacteria on Earth today. This led many scientists to conclude that they had found evidence that microscopic life had once lived in the ALH001 meteorite. However, scientists have now been able to produce similar magnetite grains under non-biological conditions, calling into question the claim that the magnetite grains are clear evidence for the presence of extra-terrestrial microscopic life in a meteorite.
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