However, they seriously don't like exposure to free oxygen :-)
TRUE, but, long chain carbon molecules don't like oxygen either, infact most early life was killed by oxygen.
The whole reason oxygen breathing organisisms dominate the planet earth (right behind carbondioxide breathers) is this.
Most methane breathers exhale oxygen, most carbon dioxide breathers exhale oxygen, most(all?) oxygen breathers exhale carbon dioxide.
So while early earth was saturated in methane and carbon dioxide, most things produced alot of oxygen. When methane breathers breathed oxygen, they litterally burned up, too much energy at once. carbon dioxide breathers choked on the oxygen.
The oxygen continued to rise uncontrolled, eventually escaping into the atmosphere. mixing in the atmosphere with vast amount of methane ofcourse resulted in a very explosive atmosphere. Lightening would spark vast firestorms that would race across the sky, devouring the methane, and the oxygen, producing alot of carbon dioxide. The methane breathers gasped for breathe as the methane was rapidly depleted. Most ofthe methane breathers died, leaving only the ones clutching to life in the bottoms of the deep oceans. Meanwhile a new form of life had come around, an oxygen breather, it stayed close to the carbon dioxide breathers who were busy producing oxygen from the almost completely carbon dioxide atmosphere.
now we all know that carbon dioxide is a green house gas, but what you might not know, is methane is a much better greenhouse gas, the world has been kept at a good warm tempreture in the early solar system, when the sun was a little bit cooler, the loss of the methane resulted in the first of many ice ages to come, the big ice age, snowball earth. Glaciers covered the continent(s) [this is pre-pangea], the oceans froze over, the ice at the equator was hungreds maybe even thousands of feet deep. The world was seemingly dead. Beneath the ice, life continued, co2 breathers clung to the ice, straining to feel the light that only barely trickleded through (ice being less dense then water allows light deeper down, though more scattered) the o2 breathers hung close to thier vital air supply. some of the o2 beathers eventually started munching on the co2 breathers, which threatened the vital o2. other o2 breathers responded by munching on the 'herbivores'
Above the ice, as the sun grows still hotter, the co2 starts playing it's role as a greenhouse gas and the world over tho course of 100,000 years begins to defrost. When the first openings in the ice occurs, the 02 escapes into the atmosphere, slowing the warming process. it will take a million years before the ice fully recedes into nothing more than caps.
The co2 breathers at the gaps explode in numbers, and produce massive amounts of o2, the o2 breathers explode in numbers as well, consuming the o2 almost as fast as it's produced, but massive amounts of the cooling o2 gas still makes it's way into the atmosphere, to play havoc at a later date. in the ice gaps near land, some of the plants, make thier way onto living on shore, just a slime at the edge of the oceans. some of the minute animals, also pull thier hard exoskeletal bodies to shore, and feed on this slimey plant life.
The bugs find the reproductive parts of the plant to be the most nurishing, so the plants that keep those parts highest out of reach of the bugs survive more often, they quickly grow to an inch in height, far from the mearly microscopic bugs reach. some of the bugs respond, by learning to jump, others devolop pointy protrusions which gives them a better grip for climbing or pulling, while others devlop both. The plants grow still taller, and taller stretching upwards, to a foot, then a meter, and tens of meters. some of the bugs eventually grow wings, and learn to fly, and thus began the age of insects, and the end of snowball earth.
Snowball earth was the 2nd cataclysm (that i know of). the first created the moon, which would shape life for thousands of millenia to come.
-- Back to Mars --
Mars is in a very extended snowball stage, one that is difficult to recover from, but all it would have taken is a single microbe to survive the initial cataclysm, and mars will be teeming with life, across its surface, probably single cellular, or maybe even sub scopic multicellular. the conditions of mars are not friendly enough for anything much larger then a large flea. such creatures will likely stay very close to thier food source, maybe even farming it like some ants do. most likely in underground colonies, where they can control the enviromental conditions somewhat.
Martian colonial creatures might do various things to improve thier living conditions. One that seems quite possible, but that i have not even heard of earth life doing. Is pressuring thier underground colonies, with a series of airlocks. The airlocks (and all walls of the colony) would be made of some excreted material which is consumed and re-excreted to open and close them. inside the colony, the creatures would have a larger tempreture range in which water could exist in liquid form.
The tempreture would be kept in this range by collections of well fed organisms, which constantly vibrate thier bodies to generate heat.
Pressure would be maintained by some of the creatures going outside, taking a deep breathe, and going back inside to exhale it.
To gather liquid water for thier gardens, they would likely excrete an antifreeze onto some frost in the early morning to melt it, then sip it up.
If thier gardens required atleast some light, i could see them packing the 'martian plants' into thier bodies and taking them to the surface at dawn, keeping thier insides pressurized for the benifit of the gardens, and laying in the sun until dusk. during this time they would be tended by others of thier colony providing water and nutrients the gardens would need during the day.
There would ofcourse also be solitary creatures which raid the colonial creatures nests, for food, wither it be the colonial creatures themselves, or the gardens they tend.
The raider would either have a burrow of it's own, that it hordes it's food in, or it would freeze solid at night and hibernate, or maybe even live in the colonial creatures nest, pretending to be one of them.
The colonial creatures would have to defend thier nest from these raiders, so they would likely develop methods of fighting simular to the colonial insects of earth. apon being detected the raider would be clobered by hordes of the colonial creatures, dismembered, and used as a mulch in thier garden.
The point of this post is ofcourse, that if something survives a global catacysm it will likely adapt, the life of earth adapted to being frozen over (on multple occasions). If any life on mars survived, it will have adapted and still be there, but we probably won't see it, unless it crawls across the camera lens, because it'll be quite small. Only in abundance do things grow very big, and we can plainly see mars does not have anything other then reddish soil and ice in abundance.
