So what do you think.... Black Smoker Hypothesis.... A black smoker is a hydrothermal vent or crack in the ocean crust, near mid-ocean ridges at the bottom of the ocean. Seawater circulates through these fractures in the crust. Where the water rises from these cracks, it is extremely hot, and laden with metals and ions containing sulfur. As the hot water comes in contact with the cold water of the ocean, metal sulfides precipitate, causing the water to appear black. Black smokers could have provided ideal conditions for the development of life[25-34]. Necessary nutrients would have been available. Developing organisms would have been protected from harmful ultraviolet radiation and from asteroids that were possibly still bombarding the planet at the time[27]. Further evidence to support this hypothesis is the presence of archaeobacteria in current hydrothermal vents. The archaeobacteria are the descendents of the first cellular organisms and are thought to be the most primitive organisms found on the earth[25,28,35]. Initially only quite recent fossils could be found in rocks created in hydrothermal environments. However, this year, fossils which date back 3 billion years have been discovered in hydrothermal vents by an Australian scientist. This discovery has caused the black smoker hypothesis to become more favoured by scientists. As seen in the Urey and Miller Experiment a large amount of energy is required for the beginning of life. In the Black Smoker hypothesis, the enormous heat from the interior of the earth is the provider of the energy, similar to the electricity in the Urey-Miller Experiment. Shallow Water Hypothesis This theory is very similar to the Black Smoker Hypothesis. The main difference is the location and the energy source for chemosynthesis. In this theory, life began along ocean shorelines, perhaps under rock ledges of isolated pools. Heat from the sun, UV radiation or lightning could have provided the energy required for organic molecules to be produced. When these pools of water slowly evaporated, the biological molecules became more concentrated. Clay particles, which have layered structures, could have acted to concentrate the organic compounds, to align them and catalyse polymerisation and other reactions[11,12,13,45,46]. The production of DNA and RNA and the subsequent evolution of life would have continued in the same fashion as in the black smoker hypothesis. Panspermia Panspermia is the hypothesis that life came from outer space. This hypothesis was made popular in Science Fiction and has now become accepted by many in the Scientific Community. Life may have travelled through space on a comet, meteorite or cosmic dust, possibly in the form of spores or micro-organisms[49]. Almost 10 000 tonnes of extra-terrestrial matter reaches earth each year [14]. A high percentage of this matter contains organic compounds including amino acids and even nucleotide bases (which are used to make up our RNA and DNA). The 1969 Murchison (Australia) meteorite contained 8 amino acids that are present in proteins today[47]. In 1984, a meteorite, later christened ALH84001U, was found in Antarctica. This meteorite was a piece of rock which originated 4.5 billion years ago on Mars. David S. McKay of the National Aeronautics and Space Administration Johnson Space Center and eight colleagues stated that this meteorite contained fossilized micro-organisms and other traces of life [15]. The validity of this claim is still being debated. S.W. Fox's Discovery Proteins are required for life. Amino acids are the building blocks for proteins. Biosynthesis, the polymerization of amino acids to form protein-like molecules, is an essential step in the formation of life. For amino acids to form proteins, they must lose water[40]. This process was thought to occur at temperatures over 140°C. However, the biochemist Fox and his co-workers discovered a catalyst - phosphoric acid. These researchers were able to form protein-like chains from a mixture of 18 common amino acids at only 70°C in the presence of phosphoric acid. These protein-like chains they called protenoids[41]. It is thought these are transitional structures leading to true proteins. Fox later found proteinoids, similar to those he had created in his laboratory, in lava and cinders from Hawaiian volcanic vents. The amino acids formed in the volcanic vapours polymerized due to the heat of escaping gases, and formed proteinoids. Condensing agents which can stitch together amino acids to form proteins have been discovered. One of them, amidinium carbodiimide, is formed in primitive earth experiments and is effective in dilute aqueus solutions Creationism Creationism is the theory that the universe or the earth was created by supernatural beings or deities. Over time, man has developed many different creationist beliefs. These vary from culture to culture and religion to religion. Three examples are explained below:
The poll is difficult to respond to since they are not mutually exclusive. Personally, I believe in God/Shallow Water & Black Smoker, etc./Panspermia.
What about the Great Chicken that laid the Planetary Egg? I refuse to vote if you don't put the Great Chicken in. What kind of poll is this?!
What's with PSJ posting polls about life's greatest mysteries? The beginning of life and the "Best Flavor" debate...in one day?
Didn't they explain all this on Star Trek? S.W. Fox's discovery makes the most sense to me. It also seems to be the most well thought out of the theories listed here. The Interplanetary Chicken concept, though, that's pretty good too.
The scientist in me belives the theory of the big bang, and then earth just happened to fall into the right place (mild climate etc..) and some cells developed from that. But my other side believes god created the earth and basic life forms- then he 'stood back and watched what evolved from it'. I'm sorry, but the Adam and Eve Story has nothing against the theory of evolution.
Good read Finn. Very technical and takes you down to the molecular level. Although, I had to laugh when I actually saw the word Chicken in there. I almost burst out . I don't know what to think, but I know that I'm more scientist than anything else. I'm suprised to see that science is getting a buttox whooping in the poll. There is a show about this stuff on TLC this week with the Jurassic guy. Searching for Life or something like that. It's all very interesting, but I don't know that I'd want to meet a potential life form, as they suggest, on another planet. The whole world is eating something and I don't want to find out that some other life form could eat me.
