I know what you are thinking. “What does this guy think he is doing, trying to answer the most difficult question in biology in a bio blog.” Well I assure you, that is not what I am trying to do, I am not that crazy.
But the question of the origin of life is a huge, biting question, and sometimes it is so formidable that we ignore it. Biology students and teacher and professors alike sometimes shove the question out of sight, procrastinating answer it just as much as I procrastinated writing this bio blog. This is unfortunate, and not just because procrastination is bad, but because I believe this question can one day be answered, not by ignoring it, but by discussing it. We cannot be scared to ask a question, even if answering it seems impossible.
So I would like the discussion to begin with me sharing what I read about in a book. Last semester I read The Vital Question, by Nick Lane. This book went into detail about two questions, the origin of life and the origin or eukaryotic organisms. Both questions are interesting, but the first was truly fascinating, and I read the entire thing in probably three days.
You see, there are many theories of the origin of life, I won’t go into all the details right now because it is a bio blog, but the most common one is that of primordial soup. You all know the story, some complex organic compounds formed when lightning struck the oceans full of the necessary elements for life. These molecules formed into a very simple thing, capable of reproducing itself. This is the theory I think is in our textbooks.
Well, in my humble opinion, this is very unsatisfactory, and in his book Lane starts out by saying this theory is outdated and probably incorrect. The experiment used to prove this (Miller- Urey experiment) was simply not set up the way earth’s atmosphere actually was when it was 4 billion years ago around the time life first came around, and even if the experiment was flawless the results still left some gaping holes.
He then discussed various other theories that I’m not going to go into detail about, and stated why he thought they did not hold up to scrutiny. Then he suggested something new, something I had never heard before.
Hydrothermal vents. Some Hydrothermal vents, not the ones that billow out smoke but the ones that release heat more gradually (White smokers and opposed to black smokers) could be perfect nurseries for the first living things. They contain plenty of the necessary elemental building blocks for life, and also last for 100,000 years, long enough for a protocell to evolve into a full-fledged organism. The key behind this theory is energy. All living things need energy, and e steady source of thermal energy from the earth could have provided that.
He explains how the first living things could have been proton cells living inside of naturally occurring pores in the vents. He also suggested that this environment would have been perfect for the creation of cells that get energy from proton gradients, the mechanism we studied in oxidative phosphorylation. The pores in the vents would have been perfect to foster naturally occurring proton gradients powering the protocells, and supported by these the cells could slowly evolve the machinery to go out on their own, into the brave new world of the open ocean.
This is his theory (I mean, Lane did not come up with it but he thinks its most plausible, and backs his opinion up with 200+ pages of facts). Of course the full explanation is very complicated and would take a whole book, but this oversimplified version is the best I can do for now.
I don’t expect to really teach you anything through this, because the topic is, as I said, very complicated. What I want to do is get people thinking, researching, asking this question again. I am sure answers are out there just waiting to be found. This is not a topic that we can and should ignore, and if we don’t ask this hard question, we are missing out on the most vital question in all of biology.