The earliest life must have been something like a small single celled organism, like a bacterium. Or at least, the earliest life that we can usefully conceive of, and potentially connect with living life. It has been suggested that life could have initially evolved at the site of submarine hydrothermal vents, which is a place these days teeming with life. So, it make sense to look for fossils of these early life forms in rocks formed at hydrothermal vents, but a long time ago.
The Nuvvuagittuq belt in Quebec is a geological formation that includes such rock.
There are two basic ways to identify a tiny bacteria like life form. Well, sort of three. Method 1 is to find a physical structure that looks like the life form. So, little bacteria shaped do-dads might be bacteria fossils. Method 1a would be to find that, method 1b would be to find something slightly less direct, such as stramotlites, which is a kind of rock formed from the accumulation of bacteria byproducts. Method 2 is to look at the isotopes of key elements, usually carbon. There are a lot of ways for carbon to get mixed up in a rock. But, the non-life connected sequence of events that put carbon in a rock would sample the ambient carbon in a characteristic way. Since carbon comes in more than one stable isotope, the stable isotope ratio of the carbon in the abiogenic rock would reflect this pattern. But living systems tend to use carbon in a different way. The carbon atoms that get used by the tiny molecular processes involved in assembling molecules are biased in which carbon isotope they end up using. This results in a carbon isotope profile different than the expected ambient one, and suggests life.
… we describe putative fossilized microorganisms that are at least 3,770 million and possibly 4,280 million years old in ferruginous sedimentary rocks, interpreted as seafloor-hydrothermal vent-related precipitates, from the Nuvvuagittuq belt in Quebec, Canada. These structures occur as micrometre-scale haematite tubes and filaments with morphologies and mineral assemblages similar to those of filamentous microorganisms from modern hydrothermal vent precipitates and analogous microfossils in younger rocks. The Nuvvuagittuq rocks contain isotopically light carbon in carbonate and carbonaceous material, which occurs as graphitic inclusions in diagenetic carbonate rosettes, apatite blades intergrown among carbonate rosettes and magnetite–haematite granules, and is associated with carbonate in direct contact with the putative microfossils. Collectively, these observations are consistent with an oxidized biomass and provide evidence for biological activity in submarine-hydrothermal environments more than 3,770 million years ago.
I used to work down the hall from a guy who was involved in the search for early life. I won’t mention names, but at the time, I remember the fighting among scientists about whether or not this or that piece of evidence was legit was pretty intense. I think things have calmed down a bit. Back then, the battle was between Australia and Greenland. These days, apparently, Canada is in the act.
At present, the oldest evidence of life that is widely accepted is probably close to about 3.0 mya, with several older sites in contention. The newest find, as noted, dates to between 3.77 and 4.28 billion, and I understand the dates are somewhat controversial. If this site ends up as representing early life, it may well be the earliest, assuming the date is anywhere in this range. There are other cases that are close to 3.8 billion but the current study’s argument may be stronger. Over the last few years, the very nature of the study of early life on earth has gained a significant amount of perspective and methodological philosophy which I think will allow future work to be considered more sensibly. By this, I mean, that rather than asserting that this or that evidence is certainly indicative of early life vs. not conclusive (or not evidence of life) we will start seeing a more unified characterization of early environments and conditions, along side a better set of models for how life could originate. In that context we may never have an “earliest life” fossil, but we may have a much better story to tell about how early life could start.
I’ll add this: Consider the number of scientists working on a problem like aging in muscles, or how to attack a certain kind of cancer. Tens of thousands. Now, consider the number of scientists dedicated to working on the origin of life. Not many. Given the magnitude and difficulty of the problem — in the field, in the lab, and in the theories — there is no wonder it is taking science many decades to nail this problem down.
Over the last several months, a lot of great books on fossils and evolution (as in paleontology) have come out. I’ve selected the best for your consideration. These are great gifts for your favorite science-loving nephew, life science teaching cousin, or local school library. Actually, you might like some of these yourself.
Grandmother Fish is the first book to teach evolution to preschoolers. While listening to the story, the child mimics the motions and sounds of our ancestors, such as wiggling like a fish or hooting like an ape. Like magic, evolution becomes fun, accessible, and personal. Grandmother Fish will be a full-size (10 x 8), full-color, 32-page, hardback book full of appealing animal illustrations, perfect for your bookshelf. US publishers consider evolution to be too “hot” a topic for children, but with your help we can make this book happen ourselves.
I reviewed the book here before it first came out. This was a kickstarter project, and it may be currently unavailable commercially, but if you click through to the kickstarter project you can probably get a copy of it.
One might ask, “how do you choose 25 fossils, among so many choices, to represent evolution?” Well, Don cheated a little by mentioning more than 25 fossils. Also, you really can’t do this. Don selected fossils using several criteria, but one basis for his choice was the availability of rich historical information about a fossil’s discovery, interpretation, and effect on our thinking about evolution. And, he covers all of that.
Don is one of those rare authors who is both an expert scientist and a great writer, with a proven ability to explain things in a way that is not watered down yet totally accessible.
Here’s a selection of the many other books written by Prothero:
Evolution: The Whole Story is an astonishing book that needs to be on the bookshelf of anyone interested in evolution. The work is edied by Steve Parker, but authored by nearly a dozen experts in various subfields of fossils and evolution, so it is authoritative and scholarly. At the same time, it is very accessible and enjoyable. This is not a book you read from cover to cover, though you could. Feel free to skip around, and you;ll find yourself looking stuff up all the time.
The book is divided into major sections, and each section has a series of short pieces on this or that fossil, group of fossils, type of life system, method for studying fossils, etc. There is a running sidebar on the bottom of many pages giving “key events” in evolutionary history of the group of life forms under consideration The book is VERY richly illustrated, with detailed keys to the illustrations. Many of the illustrations are broken down into “focal points” that expand significantly on the illustrations’ details. There are countless additional inserts with more information. The book itself is beautiful, intriguingly organized, and it is full of … well, everything. The book is very well indexed and sourced, and has helpful, up to date, phylogenies and chronological graphics.
The Biology Book: From the Origin of Life to Epigenetics, 250 Milestones in the History of Biology (Sterling Milestones) by Michael Gerald and Gloria Gerald is a compendium of biological topics and key moments in the history of biological science, organized in a sort of chronological framework. Major groups (the insects, the amphibians), major ideas (Pliny’s Natural History, Ongogeny and Phylogeny), key physiological and developmental concepts (meiosis, mitosis, many topics in endocrinology), key fossils (like the Coelocanth) and so on are discussed, very nicely illustrated. This is almost like having a gazillian short articles from Natural History Magazine (or similar) all in one book. There are 250 biological “milestones” in all. The charming part of the book is that a milestone can be an evolutionary event, an extinction episode, the emergence of a great idea, or a particular discover. And, as noted, these are ordered across time, as well as one can, from the beginning of life to a selection of the most recent discovery. The book effectively combines history of biology (and related sciences) and the biological history itself.
Life’s Greatest Secret: The Race to Crack the Genetic Code by the well respected scientist and historian Matthew Cobb is a carefully and clearly written history of the discovery of the nature of DNA, covering a lot more than, and since, Watson and Crick. It is extremely well sourced, indexed, and supported, and very readable.
This is the detailed and authoritative work on all the elements that came together to understand the genetic code. Don’t talk about the discovery and understanding of DNA any more until you’ve read this book. From the publisher:
Life’s Greatest Secret mixes remarkable insights, theoretical dead-ends, and ingenious experiments with the swift pace of a thriller. From New York to Paris, Cambridge, Massachusetts, to Cambridge, England, and London to Moscow, the greatest discovery of twentieth-century biology was truly a global feat. Biologist and historian of science Matthew Cobb gives the full and rich account of the cooperation and competition between the eccentric characters—mathematicians, physicists, information theorists, and biologists—who contributed to this revolutionary new science. And, while every new discovery was a leap forward for science, Cobb shows how every new answer inevitably led to new questions that were at least as difficult to answer: just ask anyone who had hoped that the successful completion of the Human Genome Project was going to truly yield the book of life, or that a better understanding of epigenetics or “junk DNA” was going to be the final piece of the puzzle. But the setbacks and unexpected discoveries are what make the science exciting, and it is Matthew Cobb’s telling that makes them worth reading. This is a riveting story of humans exploring what it is that makes us human and how the world works, and it is essential reading for anyone who’d like to explore those questions for themselves.
Eldredge’s groundbreaking work is now accepted as the definitive statement of how life as we know it evolved on Earth. This book chronicles how Eldredge made his discoveries and traces the history of life through the lenses of paleontology, geology, ecology, anthropology, biology, genetics, zoology, mammalogy, herpetology, entomology and botany. While rigorously accurate, the text is accessible, engaging and free of jargon.
Honorable Mentions: Older books that are great and may now be avaialable for much reduced prices.
You know about the Atheists Nightmare, right? Also known as the Evolutionists Nightmare. No? It goes like this:
That’s pretty darn convincing. Until someone opens up some closed thing and there is some new species in there, then EVOLUTION IS MADE UP!!!1!!!
Well, it turns out, Evolution is True. Some guy on the internet opened up an Oreo Cookie and inside was a new organism that could only be there IF IT EVOVED IN SIDE THE COOKIE!!1!! Look here’s a picture:
Imagine a “primordial soup” on some planet somewhere from which there occasionally emerges a thing that could locomote, and as it locomoted around it would scrape up some of the dust that lay around on the planet, and occasionally eat other things that had come out of the “primordial soup” and it would thus grow. Eventually it would wear out as its molecules, put together by some chemical process of abiogenecis in the aforementioned soup, and thusly worn out, molecules broken down by ultraviolet rays from the nearby star, it would eventually stop moving and remain exposed to the elements and dry out and become part of the dust, to be scraped up and consumed by other things.
Imagine that dozens of shallow seas of primordial soup on this planet each produced a range of such things, and they moved around on the planet, some staying in the soup, some going onto land, interacting, competing, cooperating, eating each other, sliding past each other, being born of the soup and dying, the dust sometimes being blown back into the soupy seas or being scraped up by other things.
The things are alive, right?
What if there was a form of thing on some other planet that had crawled out of the ooze and over time evolved, changed, varied, but over even longer periods of time, a self replicating version of this thing, or set of things, developed a way of perfectly identifying copies of itself that were not perfect, and destroying them. Say this emerged in several lineages of things, and this invariance gave some advantage to the things that did this. All other things, the ones that vary and change over generational time, are out-competed and those lineages disappear. So eventually, there are dozens of lineages of distinct but invariant things walking, sliding, coasting, flying, around on the surface of this planet, replicating but always duplicating perfectly, for hundreds of thousands of generations.
These things are alive, right?
Not according to Edward Trifonov, who defines life as:
I heard it said recently that “Evolution” and “Origin of life” are two separate issues. I know that this is a falsehood, and I’ll discuss in a moment how and why it is not true. But first, I checked around with a few people that I know and love, and found out that some of them assumed this was true. I think it is something that has been said enough times that if you are not personally engaged in the research or just don’t think about it enough, you can easily assume that this is what the experts say. But they don’t. Continue reading Is the origin of life different from evolution?→
Some years ago, I was asked by a friend to accompany him on a visit to a site in Saratoga Springs, New York, where we were to witness the activities of a gen-u-wine geomancer. I had never heard of a geomancer before. If you don’t know what one is, be happy. If you do, you have my sympathies. The thing is, this geomancer wanted to geomance (I just verbed his noun) with these rocks in or near a place called Lester Park. Now, if you’ve heard of Lester Park you may be thinking you know which rocks this guy wanted to commune with, but you are probably wrong. Lester park has some of the most famous rocks in the world, and then it’s got these other rocks. The other rocks are geologically interesting. They are small formations, ranging from the size of a van to the size of a cottage sticking up out of an otherwise flattish landscape. It appears that the parent rock of the area, which I take to be some kind of schist or otherwise highly metamorphosed stuff, had some force act on it to cause vertical parts to be slightly more resistant to erosion and thus stick up above the other rock. Personally, I think it might be diagenesis concentrated along joints or fissures of some kind, where hot gasses were allowed to mingle with rock under great pressure, deep below the surface of the earth in the depth of time. The geomancer thought it was energy flux lines passing through the earth and linking these rocks to Buddhist Temples in Asia. I came to my conclusion using the old fashioned scientific technique of guessing. He came to his conclusion using a bent coat hanger.
Anyway, not far from this spot, in Lester Park, one finds this rock:
In his highly readable book, One Long Argument, Ernst Mayr breaks down the body of thought often referred to as “Darwin’s Theory” into five separate and distinct theories, the second of which being “common descent.” Darwin’s second evolutionary theory (second by Mayr’s count, not Darwin’s) is really a hypothesis that could be worded this way:
All life on earth descended from a single, original, primordial form that arose eons ago.