4 ms·

Why not literally a plant? Like leafy, relies on water, comes from a small seed, reproduces via pollen/wind, based on a cell structure. We have plants in the d

by brador 14y ago

Why not literally a plant? Like leafy, relies on water, comes from a small seed, reproduces via pollen/wind, based on a cell structure. We have plants in the desert here on Earth that blossom once every X years or decades. Is there a reason such a "plant" could not have survived the harsh later years of mars post surface water? Bonus idea: if these are plants relying on ground water, their location would give away the position of said ground water. They could be mapped and their spacial density used to find source pools for humans to tap.

nollidge 14y ago
How would those plants have gotten onto the surface Mars?
- brador 14y ago
  How did they get here?
  - jlgreco 14y ago
    If we ever confirm life on Mars (or anywhere else for that matter), I really hope we don't find that it shares a common ancestor with life on Earth. Panspermia is cool, but two instances of abiogenesis in a single solar system? That is huge. Here's to hoping it's life, but not as we know it.
    - its_so_on 14y ago
      "I really hope we don't find that it shares a common ancestor with life on Earth". Could you give a definition here (of 'common ancestor'), please? I don't have an angle here, I'm just trying to understand your statement better. - tagged #rational
    - jlgreco 14y ago
      @its_so_on: >"I really hope we don't find that it shares a common ancestor with life on Earth". Could you give a definition here, please? I cannot respond to you directly, but sure. When I say I hope there is not a "common ancestor" I mean that I hope life on Earth and life anywhere else we may discover it do not have "common descent" (http://en.wikipedia.org/wiki/Common_descent http://en.wikipedia.org/wiki/Common_descent). That is strongly believed to be the case with all life we have encountered so far. This is also a pretty good wikipedia page about this: http://en.wikipedia.org/wiki/Last_universal_ancestor http://en.wikipedia.org/wiki/Last_universal_ancestor
  - nollidge 14y ago
    They evolved. For plants to be on Mars, either A) the immeasurably chaotic process of evolution yielded carbon-based, cellular, stationary, metabolizing, photosynthetic, reproductive things on two planets with vastly different geological and climatic histories, or B) Earth-borne plant material, which has evolved to the point that it can only produce a viable organism in certain rather specific environmental niches on its home planet, has somehow reached a foreign planet and developed into a more-or-less thriving colony of vegetation upon it. Neither of those seems terribly likely.
    - jlgreco 14y ago
      Re: Option A We obviously are operating with an extremely limited dataset (currently of size "1"), but there are a few things we can look at that may tell us something about the likelihood of particular characteristics evolving. We know that flight has evolved on Earth at least four completely distinct times (no common flying ancestors): birds, bats, bugs, and pterosaurs. The basics of eyes are thought to share a common ancestor, but complex image forming eyes are thought to have evolved dozens of times. I'm sure there are many better examples; I have only studied biology in my spare time as an adult, so maybe a biologist can step in. The basic idea though is that since the driving force behind the change is not random certain general ideas are likely to keep on popping up over time. Now, are the building blocks likely to be the same? Hard to say, the chemistry for carbon based life works particularly well, but there are hypothetical alternatives. I can't speak to which is more likely than the other. The question of "how likely is this" is really quite involved.
ChuckMcM 14y ago
Because plants, of the leafy green variety, have a complex evolutionary history with lots of side trips (like lichen and mold and algae). Further earth based plants are based on the same basic DNA structure as earth based animals. So while it is not "impossible" that an equivalent to plants evolved into exactly one species or micro-eco-system which exists in this one place on Mars, the chance that this occurred and didn't cause the whole planet to have evidence of their existence is really really small. But don't let that discourage you from trying various plant hypotheses. The way to pursue that is to then try to figure out what things would be true if they were plants, and see if any of the data we have from Mars would allow you to get closer to proving or disproving your hypothesis. The last time I checked you could ask for and get the a copy of the raw data from JPL if you asked for it (well not some 'give me all your data' kind of ask, but "I'd like to get HiRise imagery from this part of the planet ...")
- CoryG89 14y ago
  I was thinking more along the lines of something akin to some kind of extremophile black mold, or lichen/algae.
- hydian 14y ago
  They could have come down from an external source.
  - ChuckMcM 14y ago
    Yes, they could. But can you include some reasoning with how they would have done that? Some sound more likely than others. The panspermia theory [1] is based on the idea that perhaps some forms of life could exist in space as it transits from place to place. One of the things that has always bothered me about that hypothesis is the orbital mechanics. Which is to say if you posit a supernova or other energetic event that accelerated a planet (or fragments of that planet) into space, and somehow the life on those fragments survived both the radiation and the effects of vacuum on volatiles, and then it arrived in our solar system, what would the relative velocities be of that material with respect to our planets? And then when that material impacted a local rocky planet how much energy would be released and how would it survive that? The 'primordial soup' theories have thus always held more interest for me as being more probable. With papers like this one: http://arstechnica.com/science/2012/10/simple-reaction-makes-the-building-blocks-of-a-nucleic-acid/ http://arstechnica.com/science/2012/10/simple-reaction-makes... lending a bit of narrative around how it might have occurred. But the primordial soup theories also need evolution to get from a happenstance chemical mixture into something like multi-cellular organisms. So follow your chain of reasoning and see what questions it leads you to: "down from an external source" ... From where? How did the plant get there to come down? What is needed to survive a fall from space? At what velocities? Etc. [1] https://en.wikipedia.org/wiki/Panspermia https://en.wikipedia.org/wiki/Panspermia
dredmorbius 14y ago
"Lithops", or stone plants, fascinate me: https://en.wikipedia.org/wiki/Lithops https://en.wikipedia.org/wiki/Lithops
- ChuckMcM 14y ago
  Ok, those are some cool plants. One data bit in favor of the plant hypothesis would be the methane blooms that occur on the planet, but sadly that has a more mundane explanation as well : http://www.sciencedaily.com/releases/2012/05/120531112349.htm http://www.sciencedaily.com/releases/2012/05/120531112349.ht...

by brador 14y ago

nollidge 14y ago

How would those plants have gotten onto the surface Mars?

brador 14y ago
How did they get here?
- jlgreco 14y ago
  If we ever confirm life on Mars (or anywhere else for that matter), I really hope we don't find that it shares a common ancestor with life on Earth. Panspermia is cool, but two instances of abiogenesis in a single solar system? That is huge. Here's to hoping it's life, but not as we know it.
  - its_so_on 14y ago
    "I really hope we don't find that it shares a common ancestor with life on Earth". Could you give a definition here (of 'common ancestor'), please? I don't have an angle here, I'm just trying to understand your statement better. - tagged #rational
  - jlgreco 14y ago
    @its_so_on: >"I really hope we don't find that it shares a common ancestor with life on Earth". Could you give a definition here, please? I cannot respond to you directly, but sure. When I say I hope there is not a "common ancestor" I mean that I hope life on Earth and life anywhere else we may discover it do not have "common descent" (http://en.wikipedia.org/wiki/Common_descent http://en.wikipedia.org/wiki/Common_descent). That is strongly believed to be the case with all life we have encountered so far. This is also a pretty good wikipedia page about this: http://en.wikipedia.org/wiki/Last_universal_ancestor http://en.wikipedia.org/wiki/Last_universal_ancestor
- nollidge 14y ago
  They evolved. For plants to be on Mars, either A) the immeasurably chaotic process of evolution yielded carbon-based, cellular, stationary, metabolizing, photosynthetic, reproductive things on two planets with vastly different geological and climatic histories, or B) Earth-borne plant material, which has evolved to the point that it can only produce a viable organism in certain rather specific environmental niches on its home planet, has somehow reached a foreign planet and developed into a more-or-less thriving colony of vegetation upon it. Neither of those seems terribly likely.
  - jlgreco 14y ago
    Re: Option A We obviously are operating with an extremely limited dataset (currently of size "1"), but there are a few things we can look at that may tell us something about the likelihood of particular characteristics evolving. We know that flight has evolved on Earth at least four completely distinct times (no common flying ancestors): birds, bats, bugs, and pterosaurs. The basics of eyes are thought to share a common ancestor, but complex image forming eyes are thought to have evolved dozens of times. I'm sure there are many better examples; I have only studied biology in my spare time as an adult, so maybe a biologist can step in. The basic idea though is that since the driving force behind the change is not random certain general ideas are likely to keep on popping up over time. Now, are the building blocks likely to be the same? Hard to say, the chemistry for carbon based life works particularly well, but there are hypothetical alternatives. I can't speak to which is more likely than the other. The question of "how likely is this" is really quite involved.

ChuckMcM 14y ago

Because plants, of the leafy green variety, have a complex evolutionary history with lots of side trips (like lichen and mold and algae). Further earth based plants are based on the same basic DNA structure as earth based animals. So while it is not "impossible" that an equivalent to plants evolved into exactly one species or micro-eco-system which exists in this one place on Mars, the chance that this occurred and didn't cause the whole planet to have evidence of their existence is really really small. But don't let that discourage you from trying various plant hypotheses. The way to pursue that is to then try to figure out what things would be true if they were plants, and see if any of the data we have from Mars would allow you to get closer to proving or disproving your hypothesis. The last time I checked you could ask for and get the a copy of the raw data from JPL if you asked for it (well not some 'give me all your data' kind of ask, but "I'd like to get HiRise imagery from this part of the planet ...")

CoryG89 14y ago
I was thinking more along the lines of something akin to some kind of extremophile black mold, or lichen/algae.
hydian 14y ago
They could have come down from an external source.
- ChuckMcM 14y ago
  Yes, they could. But can you include some reasoning with how they would have done that? Some sound more likely than others. The panspermia theory [1] is based on the idea that perhaps some forms of life could exist in space as it transits from place to place. One of the things that has always bothered me about that hypothesis is the orbital mechanics. Which is to say if you posit a supernova or other energetic event that accelerated a planet (or fragments of that planet) into space, and somehow the life on those fragments survived both the radiation and the effects of vacuum on volatiles, and then it arrived in our solar system, what would the relative velocities be of that material with respect to our planets? And then when that material impacted a local rocky planet how much energy would be released and how would it survive that? The 'primordial soup' theories have thus always held more interest for me as being more probable. With papers like this one: http://arstechnica.com/science/2012/10/simple-reaction-makes-the-building-blocks-of-a-nucleic-acid/ http://arstechnica.com/science/2012/10/simple-reaction-makes... lending a bit of narrative around how it might have occurred. But the primordial soup theories also need evolution to get from a happenstance chemical mixture into something like multi-cellular organisms. So follow your chain of reasoning and see what questions it leads you to: "down from an external source" ... From where? How did the plant get there to come down? What is needed to survive a fall from space? At what velocities? Etc. [1] https://en.wikipedia.org/wiki/Panspermia https://en.wikipedia.org/wiki/Panspermia

dredmorbius 14y ago

"Lithops", or stone plants, fascinate me: https://en.wikipedia.org/wiki/Lithops https://en.wikipedia.org/wiki/Lithops

ChuckMcM 14y ago
Ok, those are some cool plants. One data bit in favor of the plant hypothesis would be the methane blooms that occur on the planet, but sadly that has a more mundane explanation as well : http://www.sciencedaily.com/releases/2012/05/120531112349.htm http://www.sciencedaily.com/releases/2012/05/120531112349.ht...