Noosa River: Millions of years ago, plants created muds and channeled rivers, which ultimately led to forests and farmland.
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Astronomers are finding lots of exoplanets that are orbiting stars like the sun, significantly raising the odds that we will find a similar world. But if we do, the chance that the surface of that planet will look like ours is very small, thanks to an unlikely culprit: plants.
We all know how Earth's landscape came about, right? Oceans and land masses formed, mountains rose, and precipitation washed over its surface; rivers weathered bare rock to create soil and plants took root. Well, new research indicates that the last stage of this scenario is not right. Vascular plants—those with structures such as xylem and phloem that can conduct water—are what created the rivers and muds that built the soils that led to forests and farmland.
The evidence that vascular plants were a primary force that shaped Earth's surface is laid out in a special issue of Nature Geoscience, posted online today. (Scientific American is part of Nature Publishing Group.) In one article, Timothy Lenton, an Earth systems scientist at the University of Exeter in England, presents data from the biogeochemical record showing that the evolution of vascular plants around 450 million years ago is what really began to soak up carbon dioxide from the atmosphere, more so than organisms in the oceans. As a result, global temperatures dropped, initiating a cycle of widespread glaciation and melting that, over millions more years, would significantly grind Earth’s surface.
Perhaps even more surprisingly, vascular plants formed the kinds of rivers we see around us today, according to another article by Martin Gibling of Dalhousie University in Nova Scotia and Neil Davies of the University of Ghent in Belgium, who analyzed sediment deposition going back hundreds of millions of years. Before the era of plants, water ran over Earth's landmasses in broad sheets, with no defined courses. Only when enough vegetation grew to break down rock into minerals and mud, and then hold that mud in place, did river banks form and begin to channel the water. The channeling led to periodic flooding that deposited sediment over broad areas, building up rich soil. The soil allowed trees to take root. Their woody debris fell into the rivers, creating logjams that rapidly created new channels and caused even more flooding, setting up a feedback loop that eventually supported forests and fertile plains.
"Sedimentary rocks, before plants, contained almost no mud," explains Gibling, a professor of Earth science at Dalhousie. "But after plants developed, the mud content increased dramatically. Muddy landscapes expanded greatly. A new kind of eco-space was created that wasn't there before."
Which brings us to the cosmic consequences. "Plants are not passive passengers on the planet's surface system," Gibling says. "They create the surface system. Organisms tool the environment: the atmosphere, the landscapes, the oceans all develop incredible complexity once plant life grows." So as Nature Geoscience's editors state in an editorial for their special edition, "Even if there are a number of planets that could support tectonics, running water and the chemical cycles that are essential for life as we know it, it seems unlikely that any of them would look like Earth." Because even if plants do sprout, they will evolve differently, crafting a different surface on the orb they call home.
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82 Comments
Add CommentThat is a very good article to present to Mrs. Jones 3rd grade science class and very true, but for Mrs. Smith's advanced 4th grade science class, they will no doubt ask: "Where did the trees come from and how did the seeds get here, and, if something planted plant seeds on Earth, could they also planted the same seeds on other planets, and if they didn't - why not? For surely the Earth is not alone in the Universe and no one has a copying machine.
Reply | Report Abuse | Link to thisMaybe "The Hitchhiker's Guide To The Universe" is correct when it said that Earth is a lab dish, the humans are the experiments and the mice are the scientists doing the experiments and we only mimic what the mice tells us to.
Where did the trees come from? Something planted the seeds on Earth? Really?
Reply | Report Abuse | Link to thisHopefully the 4th grade class has a teacher that will pour a little knowledge of evolution into their little brains, lol.
Nobody hnow! We haven t thecnology to travel fast and study this new planets!
Reply | Report Abuse | Link to thisWe think who have live in another planet but this planets have one different type of live!
This article is very good.
This is a good article, but I'm wondering, in what way different? Landscape different? But, of course it will be not the same kind of continents we have, but, so different? I'll appreciate more details about this. Thank you!
Reply | Report Abuse | Link to thisthis isn't as good an article as the commenters say - there is every reason to believe that given similar conditions, the same type of evolutionary routes would be followed.
Reply | Report Abuse | Link to thisGreat Article. The interrelated systems that go to make up this universe we inhabit are an entity that recursively combines the features of its building blocks and develops, through time, a variety of localised systems. It doesn't have a human name, or a personality, nor does it wear trousers, or demand that we sing to it.
Reply | Report Abuse | Link to thisIt evolves neutrally, (not always for the benefit of these localised systems), because that is a property of it. As are we. End of Story?
Panspermia.
Reply | Report Abuse | Link to thisOkay, why don't you try pouring some knowledge of evolution into their little brains and answer the question. Where did the seeds for the plants come from? You cannot have evolution until there is something there to evolve. Where did that something come from and how did it get here, and if it got here, why can't it get to other places?
Reply | Report Abuse | Link to thisThis is an elementary article that leaves a lot of questions unanswered and your comment is just as elementary.
I'm having a hard-time believing that without plants there would be no rivers. Afterall, have we not found rivers on Titan and evidence of rivers on Mars?
Reply | Report Abuse | Link to thisYou don't need plants to break down rocks- weathering can do that.
Afterall- if you look at most underground rivers or cave systems- there are no plants breaking the rocks there.
Even without this- It seems a safe bet that "plants" - or at least organisms that can harness energy from "light" would be likely to evolve on any planet in a solar system where life is viable. Stars are probably the most consistent sources of energy out there.
"xylem and phloem" may also be a requirement of advanced life-forms. After all- it evolved seperately as "blood" for animals. A means of distributing fluids and gasses essential for the organism seems a basic need for any organism that even slightly resembles earth-like life.
Actually evolution does not explain how life began only how it continues to survive.
Reply | Report Abuse | Link to thisConsidering all of the other methods soils and landscape can be altered it would be better to say plants are a significant contributor. It is a good article because it does show how life can adjust the planet land or even climate to create the best outcomes for life to survive. After all if it was not for plants the atmosphere would have almost no oxygen and CO2 would be a thousands of times more concentrated in the atmosphere than today.
Reply | Report Abuse | Link to thisThe assumption that the ingredients to create an earth are few is somewhat inappropriate. There could easily be thousands of earth like planets with life similar to earth. The size of the planet and proximity to the sun are likely key and would probably make this kind of life each time where changing something, like distance from the sun could create a different kind of life, possibly not recognizable to us.
Reply | Report Abuse | Link to thisThere is a difference between a river and a gully. The erosion forms on Mars generally are gullies, not rivers in the sense of the Earth. But indeed - I also question the assumption that plants are necessary to form substrates and river beds and banks. Strikes me as a theory - or as ONE factor among many.
Reply | Report Abuse | Link to thisThe article is interesting, but it jumps to an impossible conclusion. There is, quite simply, no way we can be sure about the course of evolution on other planets, so it is outright unscientific to say "We will never find a planet like Earth". We might. Or might not. That remains to be seen. And we might (here I am inclinded to say "will") find things we did not expect in our wildest dreams. Nature is, after all, tremendously creative.
Reply | Report Abuse | Link to thissorry, i have to ask... what came first, the chicken or the egg?
Reply | Report Abuse | Link to thisThis adds strength to the Gaia hypothesis that James Lovelock advanced back in the 70's. Life does have a significant role in shaping the planet and it leaves a strong signature. The planet is a complex system and the components have co-evolved to create their home as well as benefit from what it offers.
Reply | Report Abuse | Link to thisIt is very clear that you are from Mrs. Jones 3rd grade science class. Leaving a wise-ass remark is not the correct answer. Maybe your elementary mind could not understand the question: Where did the seeds for the plants come from and how did they get here? Did they just magically appear when the Earth was formed over 4 billion years ago, or did a giant seed pod accidentally drift into our gravity and explode, spreading over 15,000,000 different kinds of seeds over the Earth? Maybe that same seed pod spread hundreds of millions of strands of DNA over the planet too. You are in the remedial class aren't you?
Reply | Report Abuse | Link to thisApologies for mentioning this while you are extolling your knowledge of science, but the plants in the articles discussed existed before the evolution of the seed habit. Carry on.
Reply | Report Abuse | Link to this"Before the era of plants, water ran over Earth's landmasses in broad sheets, with no defined courses. Only when enough vegetation grew to break down rock into minerals and mud, and then hold that mud in place, did river banks form and begin to channel the water."
Reply | Report Abuse | Link to thisHose down a driveway or sidewalk much?
Water on an inclined surface (no matter how slight) has a way of finding the most insignificant topographical low spots. Unless the water's volume and corresponding flow rate overcome surface irregularities, it will eventually form rivulets.
Plants need not enter into the equation.
Well, that's all fine and dandy - except for those pesky Humans. Anything humans do is mote in Gaia's eye. They're always leaving footprints and candy-wrappers about.
Reply | Report Abuse | Link to thisThere's a crucial difference between rivulets and rivers: rivers are semi-permanent features of a landscape, rivulets disappear once the water stops falling from the sky.
Reply | Report Abuse | Link to thisSaying we'll never find a planet like Earth depends on the definition of "like".
Reply | Report Abuse | Link to thisCertainly we'll not find a precise copy of Earth. That's not to say a precise copy doesn't exist, it's just that the chances of finding it are pretty darn small.
If what is meant by "like" is along the lines of finding a planet possessing liquid water oceans, rain, land-masses and carbon-based organisms, then what you're saying is laughably improbable. Of course things on that planet are very likely to be novel in appearance, to say the least. My bet is they're gonna have rivers, regardless of vegetation or the lack thereof.
Whether we're talking rivulets or rivers, brooks or streams, they all have a source, whether that source is a lake, spring or summer thunderstorm.
Reply | Report Abuse | Link to thisThe proposition that water flowed in broad sheets across the landscape before the existence of vegetation is ridiculous. My analogy depends on natural surface irregularities and gravity. The water's source is irrelevant.
Rivers disappear when you dam them. There is no "crucial" difference between a rivulet or a river.
Reply | Report Abuse | Link to thisA river can be made to disappear if you dam it at its source(s), and channel the water to a far off area so as to minimize its eventual return to the now dry riverbed.
Reply | Report Abuse | Link to thisIf the riverbed exists in an arid environment, perhaps it will stay dry almost all of the time - which would qualify it as a "rivulet" when flooded during the rare downpour.
You should probably go and read the original papers - your arguments are pretty off-topic to what they said (and some of your conceptions of rivers, while I don't doubt they are well-meaning, are demonstrably wrong).
Reply | Report Abuse | Link to thisAgree with most that this is a good article, and that plants have had significant impact on geology of Earth. However there are already features identified on Mars and Titan that I think disagree with conclusion that you can't have sediment and river channels without plants.
Reply | Report Abuse | Link to thisIf your a Darwinist then the Egg containing todays chicken came first from the chickens precursor and if your a theologist then the chicken just appeared one day. I hope that puts that question to rest forever.
Reply | Report Abuse | Link to thisdtinc, there is no reason to believe that, given similar conditions, the same type of evolutionary routes would be followed.
Reply | Report Abuse | Link to thisImagine I show you my car. It's the only car you've ever seen. Can you conclude from that example that all cars are blue?
What has happened on Earth is just one example. We need more examples to decide which aspects of life here are pretty much universal (four wheels), which are relatively rare (blue colour), and which are idiosyncratic (can of WD40 in cup holder).
Really? This is scientific communication in the 21st century? A series of peer-reviewed articles by various career scientists, concisely summarised in an articulate way by a professional journalist... and yet most of the words on this webpage are now written by an anonymous poster with a lot of opinions formed around the fact that they once washed their car and saw water running onto the sidewalk. Ah well, intelligent thought is probably over-rated anyway, right?
Reply | Report Abuse | Link to thisIs the author a physicist? Given the ubiquity of photosynthesis and the principle of convergence it is hard to imaging that if multicellular life evolves plant analogs won't almost of necessity evolve. Surely there will be moss-like pioneers, then herbs, then trees to outcompete them for light, then vines to grow on the trees. These are all relatively basic solutions to universal problems. The evolution of sexual reproduction is the surprise event in the history of our planet, not the emergence of photosynthesizing muticellular land organisms.
Reply | Report Abuse | Link to thisSometimes the most sensible observations are the most mundane. The fact that the author's propositions defy known physics, as well as common sense, has no bearing on the car-washing habits of others.
Reply | Report Abuse | Link to this"Professional journalist"...
Reply | Report Abuse | Link to thisI'm still laughing, midmo. Thanks for the comedy, you should look into a career change, it might get you out of the OWS camp you've been in since last November.
"Because even if plants do sprout, they will evolve differently"
Reply | Report Abuse | Link to thisEvolution produces divergence for a number of reasons both accidentally and for adaptive reasons - optimising for different ecological niches - but the reverse process occurs as well, evolution converges on structures that maximise adaptive function. Exo-plants will certainly evolve differently but it seems to me - admittedly on limited analysis - that they will converge on the same basic structural systems that have been wildly successful here on earth.
Oh dear, it really is what it has come to isn`t it? A conflated mess of comment-box opinions; transcending misunderstood science, guesses about politics, and who knows what else... addled brains and feverish fingers with no editorial control, spewing opinion masquerading as fact to clog up the internet til it starts heaving and groaning and cracking at the sides. Can somebody please wake me up when the machines rise up and take over? Surely it's only a matter of time before they get tired of this baloney too...
Reply | Report Abuse | Link to thisYou don't even need the "breaking down of rocks" or weathering. All you need is the probability that a sufficiently hospitable (atmospherically and mass-wise) planet has a surface that's not absolutely smooth and level.
Reply | Report Abuse | Link to thisAdd water, and Presto! Rivers... be they large or small.
Tidal forces is the key.
Reply | Report Abuse | Link to thisRiverine planetoids aside, perhaps most people have not considered the possibility that other planets may not possess gravity.
Reply | Report Abuse | Link to thisIt is plainly clear that this is kind of a weird article. If we have so many stars above in the night sky (and all around earth at any time of day or night),really millions upon millions of them, and on average we may have one planet around each one of these stars. It is pretty obvious that we have millions upon millions of planets up there in the night sky (and all around earth at any time of day or night). At least in theory I see no reason why the process that took place on earth can not be repeated some were in a may be distant (or not so distant, who knows)corner of the universe. Probably the problem with the article is the wording of it. The article does not give a clear-cut idea of why the process can not be repeated somewhere else in the universe. It would be interesting a further more detailed discussion of the subject matter. Probably is a matter of statistics and probability. I have no doubt in my mind that there is intelligent life in other parts of the universe. The question is: Why have they not contact us? And plainly, why have we not being able to contact them yet? But can you imagine what a shock that may be? Very probably the time will come.
Reply | Report Abuse | Link to thisI understand this is about the physical world and we may say the biological world. But let us go a step ahead if you permit. If we are alone in the universe. And that may be the case. Then the title of the article should be: Thanks to God, we will never find a Planet like Earth. We are the owners of the entire universe. And God is only for us. We do not have to share Him with anybody else. This idea comes to me after seeing a picture of the moon covering precisely the disk of the sun in a total sun eclipse. How in the world can it fit so precisely? And we have only one moon. Other planets in our system have several moons. No one of those moons cover the sun the way our moon does. Is that a message from heaven? Who knows? It may be.
Reply | Report Abuse | Link to this"Riverine planetoids aside, perhaps most people have not considered the possibility that other planets may not possess gravity."
Reply | Report Abuse | Link to thisThen you wouldn't be worried about jumping off a bridge on one of those planets, would you? Coincidentally, I happen to have one for sale...
Even without vascular plants, freezing and thawing of water in crevices will weather rock and create debris. As another wrote, if plants were needed, why are there channels on Mars? It might not be the same, but there would surely be rivers of a sort.
Reply | Report Abuse | Link to thisI thought there was plenty of dust (= mud without water) on Mars, without apparently plant life to create it.
Reply | Report Abuse | Link to thiswe have plenty of geologic evidence for this:
Reply | Report Abuse | Link to this"Before the era of plants, water ran over Earth's landmasses in broad sheets, with no defined courses"
so what is your problem? don't hurt yourself overthinking things.
Evolution is not necessarily required for survival. Some of the most primitive original organisms still are around, almost unchanged. Evolution explains how life branched out, adjusted, claimed new environments and ecological niches, created new environments by itself, diversified and became ever more complex, starting out from very humble beginnings.
Reply | Report Abuse | Link to this@ColinBliss: If you show me your blue car and it would be the only car I have ever seen, my conclusion would be: a blue car exists. Hence it is possible that a blue car exists. And hence it is possible that there are other blue cars.
Reply | Report Abuse | Link to thisWe still have to find out whether evolution follows universal principles leading to similar results given similar conditions. On Earth we know that convergent evolution is common, but all lifeforms here have common ancestors. Whether convergent evolution is a more universal principle - who knows? We will have to wait at least until we can do high resulution spectorscopic analysis of extrasolar planetary atmospheres. Unfortunately the Darwin Project was killed, so that isn't around the corner.
"Before the era of plants, water ran over Earth's landmasses in broad sheets, with no defined courses."
Reply | Report Abuse | Link to thisAn improbable and patently ridiculous statement, unless one were to believe that Earth was originally formed with absolute topographic uniformity and of substances impervious to erosion.
Certainly these conditions are highly unlikely and were not met during the time Earth was devoid of plants.
He was being sarcastic. The article itself posits an unlikely scenario.
Reply | Report Abuse | Link to this@QuantumQualifax:Right. There are Gullies on Mars:
Reply | Report Abuse | Link to thishttp://tinyurl.com/827ojvh
They look the same as gullies on Earth. Canons also are hardly biogenic...
"Overthinking" is a characteristic of the hypothesis described in the article. The existence of broad sheets of non-channeled water assumes two enabling conditions:
Reply | Report Abuse | Link to thisa) The Earth's surface being impervious to erosion.
b) The Earth's surface possessing no variation in topography, i.e. smoother than a billiard ball.
Besides, "broad" was not defined, and I suspect any definition of it is subjective.
Very very poor article. Not up to SciAm standards at all.
Reply | Report Abuse | Link to this"Thanks to Plants, We Will Never Find a Planet Like Earth"
So no other Planet can have plants ? ..... duh.
Well, now that is all settled, I guess science has no where to go. Too bad. Just when it was starting to make headway with AGW myth.
Reply | Report Abuse | Link to thisAll hail the great planter.
The original article by Lenton et al that is linked to is more interesting but also strikes me as somewhat speculative, despite the empirical approach. Moreover, I didn't see any conclusions whatsoever about extrasolar planets. The topic is not even mentioned. That strikes me more as a leap of faith by the good Mark Fischetti. If anything, the Lenton article shows that there are many details of Earth System Science that we really are far from understanding. To derive any broad conclusions related to the potential billion year course evolution might take on an as yet undiscovered extrasolar planet is... bold. To say it mildly. I find it interesting nevertheless to attempt a discussion of extrasolar geographies. We learn - and already learned a lot - something about our own bio-geosphere along that path. But it is a sandbox. Not more. More science fiction than science.
Reply | Report Abuse | Link to this"More science fiction than science"? On the contrary - should you follow the links to the original articles cited you'd see there's a substantial amount of evidence backing them up. Not that this isn't open to retesting or improving by further research - but that's how science works. I get the impression that it's the headline chosen for this article (by a journalist, to get people to read the article) that is causing much of the controversy (and if you follow the link to the original editorial in Nature, the premise of the headline is couched in much more cautious terms that are hard to disagree with).
Reply | Report Abuse | Link to thisThis article and its title are good to generate discussion, but I do worry that quite a few comments here miss the point that science is based on both observations and testing - and that refuting scientific claims requires further observations and testing, not just opinions, unsourced claims and anecdotal evidence. I think anyone really interested in this should follow up the three original scientific articles that are linked in the text and see if what they find really fault with is the new science, or just the headline chosen for this brief summary...
Some of you should really check out the full article on 'Natural Geoscience' before basing everything on Scientific American's short overview, as the full article is much more in-depth an less sensational.
Reply | Report Abuse | Link to thisAlso to some commenters, nowhere did the article suggest that mud, dust, sand or erosion would not happen without plant life. It was stating that one of the defining features of Earth’s surface, soil, owes its existence to those vascular plants that began evolving around 400 million years ago. Reason being is as those vascular plants began to spread, their viability rested solely on their ability to have regular access to water. However, before the presence of these plants Earth's water system was probably similar to Titans; bodies of water with few running rivers except during rainy weather, where lakes overflow and rivers run in broad shallow sheets as mentioned in the article. This wouldn't be suitable to the survival of vascular plants as they require some form of consistent water flow to live but not so much that they drown. This is where the 'terraforming' aspect mentioned comes into play. What I got from it is that early plants gradually encroached upon these ‘inefficient’ lakes and rivers (achieved by breaking down rock and accumulating mud to put simply) and pushed back, making rivers deeper an skinnier and lakes fuller an wider to the point where water can consistently flow, even with the absence of rain for weeks. In fact, you can get some semblance of what things may have appeared like before by looking at areas suffering from topsoil erosion, where riverbeds collapse and spill outwards in vast sheets ruining much of the land downstream from the afflicted area.
Finally, this doesn't assume that other hospitable planets won’t have plants, just that the composition and cycles of other worlds may drastically affect their evolution to the point where they appear and operate much differently than Earth's.
Honestly, I'm wondering if some of the commenters even bothered reading the article. lol
Again: the conclusions of the Scientific American Article seem to me to be more science fiction than science, meaning they are highly speculative. The Lenton Article is about the natural history of Earth. We cannot say anything aside from "what if" scenarios about extra solar planets within the habitable zones of their stars. It will take a while before we get high resolution spectral analysis of extrasolar planetary atmospheres that give at elast a hint of whether there is life or not. Empirical evidence for any furter details are entirely out of the question.
Reply | Report Abuse | Link to thisThe primitive plant spirogyra can reproduce sexually and asexually. Most plants would have probably have looked and behaved much the same, at first.
Reply | Report Abuse | Link to thisThe early animal life reproduced by budding or splitting in two.
Seeds came very much later. The ferns came earlier, reproducing by spores.
While many plants are pollinated by the wind, others require insects to carry the pollen. Plant and animal life would have evolved together from microscopic organisms that look very much alike.
We used to learn all this stuff in school biology lessons
years ago.
What you describe here is pretty much a summary of what I learned in physical geography classes 25 years ago. Common understanding in limnology, geo-morphology and soil scinece. That life on other planets is likely to "appear and operate much differently than Earth's" strikes me as common sense. There even may be lifeforms that would not fit any of our common classifications. No way to tell.
Reply | Report Abuse | Link to thisComparing Titan to Earth is not helpful in this context since the similarities are only superficial. Titan does not have any water/silicate/carbonate erosion. The surface is characterized by various forms of carbo hydrate and possibly water ice eroded by liquid carbo hydrates. The chemical and physical processes are totally different from the water/oxygen dominated chemistry on Earth.
Plants and animals clearly play a major role in the formation of soil, but there might be other mechanisms. Mars does apparently have soil. See for example http://scienceray.com/astronomy/and-mars-will-flower-gardens-martian-soil-suitable-for-plant-life/
Wow, talk about oversimplification. So glaciation and erosion had nothing to do with sculpting the earth's surface? That every surface was solid rock prior to the evolution of plant life? And then to jump to the conclusion that the same events that influenced the development if life on this planet could not also occur on some of the millions of other planets in our galaxy.
Reply | Report Abuse | Link to thisI ain't buyin' what they are sellin'.
Well that's the thing about science, most of it seems like common sense but until evidence comes forth to support it it's merely conjecture. I doubt much of the information in the article is ground-breaking or even remotely new to scientists; it sounds like a reassessment of existing data to give a better timeline of Earth's chronology. I'm guessing that these are pretty common in the field, so that data accumulates and evolves together and doesn't get cluttered and lead to confusing and conflicting conclusions (not an Earth scientist so I don’t know).
Reply | Report Abuse | Link to thisYour right, it was a bad comparison but it is the only extraplanetary body with flowing liquid that I could think of to show that water flows could be drastically different without vascular plants. I didn’t mean to suggest that it would be even remotely identical to early Earth (I went back and saw I put 'systems', should of put 'flow', less confusing), sorry that it came across as such.
Well soil is just nutrient rich dirt. Dirt is a common form of regolith which exists on most terrestrial bodies including the moon. It's the composition of the soil that really matters to life, and if Mars once had running water it isn't a stretch for it to have some form of healthy soil. It’s the sheer quantity of it (thanks to plants actively breaking down solid rock)that separates Earth from the others. On Mars you would only need to swipe aside the dirt to reach solid rock in most places. It’s actually why Mars lacks any massive deserts like our own Sahara, instead having modest dunes trapped within its craters or ripples flowing along its cracked surface.
The article is ridiculous speculation. There is no basis to expect plants would not evolve anywhere that life does, any more than that animals would not also evolve there.
Reply | Report Abuse | Link to thisI have been a reader of Scientific American since the early 1950s, and I am distressed at how much the technical level of its articles has been dumbed down and shortened. I do not expect articles to be at the level of Science or Nature, but I do expect them to be much more advanced than Science News. I also expect them to be written by scientists more than by science journalists.
I agree that similar conditions would create a variation on the plants, soils, and fauna that we have here. It is like convergent evolution. The oceans form fish, reptiles, birds and mammals that all have similar body configurations for the conditions that the environment require for them to best survive.
Reply | Report Abuse | Link to thisHello JamesDavis,
Reply | Report Abuse | Link to thisYou asked, "Where did the seeds come from?"
What a good question. Reading a little about vascular plants online I found that some are "seedless" vascular plants - plants that shuffle water to and fro through their stems that do not produce seeds. Well, then how do they reproduce?
Apparently, they have spores. And spores are rather hardy things - I think they can even stay viable but dormant in the vacuum of space!
So, perhaps, they evolved from one-celled organisms to many-celled organisms on another planet, then the planet was hit by a mass of some sort and a piece of that planet went flying off into the universe and hit this planet. Here, the spores found a welcome environment and began evolving into these beautiful plants:
http://hcs.osu.edu/hcs300/svp1.htm
Or, perhaps, they did all their evolving on Earth. So, where did the spored some from? Maybe they evolved from very simple one-celled, no-nucleus masses from the chemicals that make up the rock of a planet's core.
And I guess from there, we can ask, well, where did the rock come from? And on and on and on...
Timbosta and priddseren seem to be somewhat on the right track. It is not clear however priddseren if life did not originally arise due to some fundamental universal properties, such as may have promoted evolution of fairly abundant amino acids into proteins and later into protocells. The universe may produce neutral localised systems, however after the early protocells were refined by evolution into life as we know it, it is fairly clear that some element of self-organisation if not control was arising. Thus fixation of CO2 by marine algae etc. exists and some such as Lovelock have promoted the idea that Earth is a self-regulating system called Gaia. This new evidence in the article only adds to the perspective that once life did arise, Earth became a somewhat self-sustaining system, somewhat capable of influencing its own destinies. As such the biotic (living) components or the composed "system" may no longer be neutral. One must separate the non-living (abiotic) universe from the biotic which can influence the direction of events on Earth. It is not as clear if selection is non-universal, and thus evolution of some kind is not involved in the first life on Earth i.e. were proteins that clustered "selected" and did better than others. It is certainly interesting that mud is so important once it all got going! Let's hope the rivers don't return to the random state once we de-vegetate!
Reply | Report Abuse | Link to thisAussie Aussie Aussie oi oi oi- life began downunder!
Timbosta and priddseren seem to be somewhat on the right track. It is not clear however priddseren if life did not originally arise due to some fundamental universal properties, such as may have promoted evolution of fairly abundant amino acids into proteins and later into protocells. The universe may produce neutral localised systems, however after the early protocells were refined by evolution into life as we know it, it is fairly clear that some element of self-organisation if not control was arising. Thus fixation of CO2 by marine algae etc. exists and some such as Lovelock have promoted the idea that Earth is a self-regulating system called Gaia. This new evidence in the article only adds to the perspective that once life did arise, Earth became a somewhat self-sustaining system, somewhat capable of influencing its own destinies. As such the biotic (living) components or the composed "system" may no longer be neutral. One must separate the non-living (abiotic) universe from the biotic which can influence the direction of events on Earth. It is not as clear if selection is non-universal, and thus evolution of some kind is not involved in the first life on Earth i.e. were proteins that clustered "selected" and did better than others. It is certainly interesting that mud is so important once it all got going! Let's hope the rivers don't return to the random state once we de-vegetate!
Reply | Report Abuse | Link to thisAussie Aussie Aussie oi oi oi- life began downunder!
We have no data that help decide whether life on Earth -its fundamental existence and its phenomenology - is due to a common cause and thus a universal phenomenon, or due a special cause and therefore an exception.
Reply | Report Abuse | Link to thisWe also have no data whether the phenomenology of the Earth is the result of common causes or of special causes.
What nonsense discussion is this here, when we have no data at all from outside the Earth?
Isn't Science wonderful? Unlike other ideologies that the majority of the world sprout, at least Science can admit to being wrong about things when they discover something new. I am still in awe of evolution and I continue to learn more everyday.
Reply | Report Abuse | Link to thisIt might seem like a trivial beef, but the difference between "never" and "the chance...is very small" is meaningful. The title uses and absolute-"never"-that is contradicted by first paragraph.
Reply | Report Abuse | Link to thisScience is grounded in precision and rigor. This sloppiness in the article is unscientific and has no place in Scientific American.
As a side note: there's a wondering why Americans are not as scientifically aware or sophisticated as they could (should?) be. Erosion, however slowly, of intellectual standards is a bad thing and must be pointed out whenever it's encountered.
Dang. Typos in my previous comment. I hate that.
Reply | Report Abuse | Link to thisCorrections: "The title uses an absolute-"never"-that is contradicted by the first paragraph."
For what it's worth: I've been reading Scientific American for more than 40 years, and fondly remember when I discovered my friend's Father's copies. It's been one of my major pleasures.
Prof Gibling and Lenton present a viable alternative to what I was taught throughout my careers in Forestry, Chemistry and Landscape Architecture (I was lucky to receive a fantastic perspective on the biotic world through three disciplines). We were always led to believe that lichens started the evolutionary process thanks to symbiosis. It made a lot of sense and without conductive
Reply | Report Abuse | Link to thistissue such as xylem and phloem - they broke down rock through the freeze-thaw cycle on early planet Earth forming the pioneer soils through disintigration of rock. The early chloroplasts united with algae to carry out this prehistoric
function. It made perfect sense. The young sun could not supply enough radiation to generate an ecosystem on Mars and
that could explain why it did not mature as well as Earth,
as well as its lower gravity and the prospect of the solar
wind in early days blowing any relevant atmosphere off the planet. Mars will still have its chance when our star matures into a red giant and swells to the orbit of Earth,
Thisupon which time Mars will have its habitable zone. This still does not explain how algae and chloroplasts got started, or actually plants themselves. I'm going to present your theory to a large crowd I'm delivering a talk to on Sanibel Island entitled "Finding a New Planet". Its an
interesting proposition you have launched. Lets see how an
audience of 300+ professionals judge it. I'll let you know.
(Keep on investigating and do some carbon dating)
If plants are required to create channels for water, then that leaves a really obvious question hanging in the air: Where did the channels on Mars come from? Either Mars had plants at one time, or this claim is incorrect. I tend to vote for the latter...
Reply | Report Abuse | Link to thisThey came from stabilisation by ice... that's at least what it says if you follow the links and read the papers.
Reply | Report Abuse | Link to thisInteresting, but where it's right it's unoriginal, and where it's original, it's wrong. We had a major glaciation about 2300 m.y. ago and a near global one between 900 and 600 m.y. ago, well before the arrival of vascular plants. The idea that vascular plants created a carbon sink and cooled the climate has been around for quite a while. Rivers may have been more braided before vascular plants but water still flows downhill and braided rivers, like the Rio Grande, are just as capable of cutting valleys as any other kind. As for "almost no mud" before vascular plants, what exactly was the Burgess Shale made from? Google "Precambrian Shale" and see how many hits you get.
Reply | Report Abuse | Link to thisThe paper doesn't say that *all* glaciations are related to plants, but that the one at the end of the Ordovician appears to be. The other paper says there was almost no mud *on land* because there were no plants to bind or trap it: which is why it ended up in the sea for the Burgess Shale and Precambrian Shale you mention...
Reply | Report Abuse | Link to thisIt's almost as quick to click the links, read the papers, and clear up confusion, as it is to add a comment stating they are 'wrong'...
I think this area of study is almost impossible to fully understand. Why did ice ages start then stop only to restart millions of years latter? Why did all the large animals of North America die off about 12 thousand BC?
Reply | Report Abuse | Link to thisAt present we are having some wonderful climate change, for some of us, the big question is why? And so on...
richardeb
I think this area of study is almost impossible to fully understand. Why did ice ages start then stop, only to restart millions of years latter? Why did all the large animals of North America die off about 12 thousand BC?
Reply | Report Abuse | Link to thisAt present we are having some wonderful climate change, for some of us, the big question is why? And so on...
richardebridges@aol.com
As usual the headline was written by an overenthusiastic editor, I fear. But even the article overstates the case. We don't know,like in DON'T KNOW, what form life on other planets would take. But the form of trees, that is space filling branches and leaves to catch the sunlight, is highly probable. As are roots to anchor the space filling structure, and get access to water and minerals. And of course if their sun(s) are at the approximate temperature of ours, the leaves will be green, more or less. To assert there is no chance it will look like earth is just silly.
Reply | Report Abuse | Link to thisAs I mention in my ecopolitical thriller, The Carbon Trap, nonvascular plants first colonized rock surfaces and caused minerals to be released that fed phytoplankton. The result was a plunging of CO2, and then snowball Earth. When surface nutrients were used up biomass rotted, CO2 soared, THEN about 450 million years ago vascular plants arose that were able to tap into buried nutrients, and CO2 has been on a downward slope until the industrial revolution. The dearth of elemental phosphorus and other nutrients eventually removed by the roots is going to starve our planet once more of plants. Mankind's trying to turn biomass into fuel only accelerates the depletion of soil, particularly when we use all the plant for fuel and don't return anything to the soil.
Reply | Report Abuse | Link to thisI would like a climate scientist to predict what CO2 rates would have been 10-20 million years ago if mankind hadn't started recycling carbon back into the atmosphere. 540 million years ago CO2 was 7,000 ppm. 200 years ago it was 280. With exception of some major dips and rises, Earth was running out of CO2. I contend most plants would have died off.
The author's ignorance is so, so obvious in that he takes this sort of position! How he can make such an assumption "that the surface of that planet will look like ours is very small," when one considers the billion of stars that are out there ? Certainly, quite to the contrary, it would be a big surprise if there were not a planet, or planets) exactly like earth.
Reply | Report Abuse | Link to thisDid you read all the way to the end of the article? There is was written: as Nature Geoscience's editors state in an editorial for their special edition, "Even if there are a number of planets that could support tectonics, running water and the chemical cycles that are essential for life as we know it, it seems unlikely that any of them would look like Earth." Because even if plants do sprout, they will evolve differently, crafting a different surface on the orb they call home.
Reply | Report Abuse | Link to thisSo what we have is a question of "how different"? - and that we won't know until we can find and see the surface of at least one other planet with life on it... if we can find two planets with life on them and see the surface of them then we will have a better sample set (to see how different life bearing planets can appear to us) and more so as we discover more planets with life... if there are any out there. I believe we do not have enough data on the conditions needed for life to evolve on a planet. So far we have ONE sample. Maybe the window of circumstances needed is (relatively) very wide and we will find many planets with plant like life, or maybe it is (relatively) very small and there are no planets with life on them with-in 8 billion parsecs of Earth. Until we have a bigger sample size it will be very difficult to calculate "the odds" of finding life on a planet in a certain area; or how "likely" it will be for a planet with similar circumstances to have a surface "like" Earth (what-ever that means).
Did you read all the way to the end of the article? At the end the author wrote: as Nature Geoscience's editors state in an editorial for their special edition, "Even if there are a number of planets that could support tectonics, running water and the chemical cycles that are essential for life as we know it, it seems unlikely that any of them would look like Earth." Because even if plants do sprout, they will evolve differently, crafting a different surface on the orb they call home.
Reply | Report Abuse | Link to thisSo what we have is a question of "how different"? - and that we won't know until we can find and see the surface of at least one other planet with life on it... if we can find two planets with life on them and see the surface of them then we will have a better sample set (to see how different life bearing planets can appear to us) and more so as we discover more planets with life... if there are any out there. I believe we do not have enough data on the conditions needed for life to evolve on a planet. So far we have ONE sample. Maybe the window of circumstances needed is (relatively) very wide and we will find many planets with plant like life, or maybe it is (relatively) very small and there are no planets with life on them with-in 8 billion parsecs of Earth. Until we have a bigger sample size it will be very difficult to calculate "the odds" of finding life on a planet in a certain area; or how "likely" it will be for a planet with similar circumstances to have a surface "like" Earth (what-ever that means).
Carlonne, you ignorance is so, so obvious in that you take that sort of position! How can you make such an assumption that "certainly it would be a big surprise if there were not a planet, or planets exactly like earth."???
Reply | Report Abuse | Link to thisI believe you are making the error of the "infinite monkey theorem". For your reference: http://en.wikipedia.org/wiki/Infinite_monkey_theorem