What are alien lifeforms really like?

[Thunderbird]

Originally Posted by Moontanman

I agree, I think that cooperation symbiosis has done as much as competition to cause evolution. Much of what we are is due to symbiosis. Mitochondria, chloroplasts, flagella, gut bacteria, it makes sense that symbiosis will continue in the future into larger and more wide spread groups of animals.

Yes,
I intuit that what configures at the very beginning of complex life would led to radically differing ecosystems. You can take any aspect of our systems competition, adaptation, parasitism, symbioses, and just ramp one up over another. I think our own would be more a competitive system than most, but it is not the most efficient part of our system.
The dino’s were definitely completive, and successful. Flowering Plants and insects symbioses however became even more successful, evolving a more “fruitful” partnership that made our evolution possible.

More evolutionary power in a flower than teeth, so to speak.

[Boerseun]

We engage in various symbiotic relationships with quite a few species.

Consider the lowly bovine. We provide it with food and protection. It provides us with prime rib. It's a win-win situation, so much so that a cow won't survive anywhere else but under human care.

[Thunderbird]

This is part of one of my first threads on the forum.


A Teleological view of Cows, Ice cream, and Memory
A while back a friend and I were discussing why some cultures hold the cow as a sacred animal. My initial view point was that “The dog or horse were better than any ole stupid cow !” My friend who is always willing to challenge my views, said the following; “Think about this, your in a field of grass with nothing to eat, now place a cow in the field you have milk, butter, cheese, and don’t forget Haugen das Ice cream.” { He knows I like Haugen Das} “Wow, I never looked at it that way.” “Well I have to admit anything that can transform a bail of hay into ice cream must be sacred!”

[HydrogenBond]

Life on other planets will probably still use water as the basis for life. One of the practical problems with using ammonia, is it is flammable, so using ammonia would preclude using oxygen. In an oxygen atmosphere, animals would catch fire. Without oxygen as the terminal electron acceptor in metabolism we can't generate the same type of energy output. So even if life could form, its evolution would be sort of limited.

Carbon would also be hard to replace. The alternative is Silicon since it can also form four covalent bonds like carbon. The problem is the silicon versions of the carbon compounds are too stable. Once a life form made some food reserves it would be harder to get the energy back, and if it did, there is less energy there. Again we may still get some type of life but the energy limitations may limit evolution. Hydrogen will also be needed to be part of the blend. The hydrogen bonding is strong enough to allow molecule shapes but weak enough to break. Hydrogen has its own unique bond that is ideally suited for life.

The odds are the biochemistry of advanced alien life may be relatively close to that on earth. There would be some tweaks in the bio-details. But higher evolution may still use the bulk constraint of going in the direction of energy optimization. Humans have our bodies set at 98.6 F. This appears to be what the highest life form on earth requires to get the most out biology. So warmer planets may have the best shot of going furthest in evolution. For example, if humans came from apes and from Africa then warm was part of the blend. Migration to cooler climates requires the body generate more heat to stay warm. This will further increase the energy output but only after the biology was set up for 98.6F.

I tend to believe higher alien life will look very similar on the inside and under the microscope. The difference may be more in terms of the outer alien. This will be more a function of their home environment. We might get different skin textures, muscular proportions, colors, etc. Once you cover this with clothes there is less difference.

[Moontanman]

Life on other planets will probably still use water as the basis for life. One of the practical problems with using ammonia, is it is flammable, so using ammonia would preclude using oxygen. In an oxygen atmosphere, animals would catch fire. Without oxygen as the terminal electron acceptor in metabolism we can't generate the same type of energy output. So even if life could form, its evolution would be sort of limited.

Another problem with ammonia is it's affinity for water, it would be difficult to have pure ammonia oceans, in almost all cases you would have a mixture of the two since their liquid ranges not only overlap but a mixture of the two has a greater range of being liquid than either one alone. I'm not sure if a combination of the two would work. Of course you are assuming that lower temps wouldn't allow for a less energetic reaction than oxygen to allow complex life but I wouldn't hold my breath for that either.

Carbon would also be hard to replace. The alternative is Silicon since it can also form four covalent bonds like carbon. The problem is the silicon versions of the carbon compounds are too stable. Once a life form made some food reserves it would be harder to get the energy back, and if it did, there is less energy there. Again we may still get some type of life but the energy limitations may limit evolution. Hydrogen will also be needed to be part of the blend. The hydrogen bonding is strong enough to allow molecule shapes but weak enough to break. Hydrogen has its own unique bond that is ideally suited for life.

Silicon has been looked at quite closely and will almost certainly not be a basis for life at any but very low temperatures. Silicates would have to be at very high temperatures and pressures. There are other possibilities, nitrogen-phosphorus polymers, and boron.

The odds are the biochemistry of advanced alien life may be relatively close to that on earth. There would be some tweaks in the bio-details. But higher evolution may still use the bulk constraint of going in the direction of energy optimization. Humans have our bodies set at 98.6 F. This appears to be what the highest life form on earth requires to get the most out biology. So warmer planets may have the best shot of going furthest in evolution. For example, if humans came from apes and from Africa then warm was part of the blend. Migration to cooler climates requires the body generate more heat to stay warm. This will further increase the energy output but only after the biology was set up for 98.6F.
I tend to believe higher alien life will look very similar on the inside and under the microscope. The difference may be more in terms of the outer alien. This will be more a function of their home environment. We might get different skin textures, muscular proportions, colors, etc. Once you cover this with clothes there is less difference.

I have to agree with this but there are other possibilities, see the following links.

Life - but not as we know it - space - 06 June 2007 - New Scientist Space

boron-based life

ammonia-based life

silicon-based life

nitrogen-based life

Alternative biochemistry - Wikipedia, the free encyclopedia

[Thunderbird]

As I was watching the movie A.I. I could imagine a fossil record of carbon based life strata followed by a layer of silicon based life forms, that could survive some disaster the fragile forms could not. Then a biological period of a human race #2 by the robot's re-created when the conditions improved. It would make a good scifi book.

[mynah]

Could "little green men" really exist somewhere in the universe, if not on Mars? Why has no multicellular photosynthetic organism capable of independent movement evolved on earth?

[Thunderbird]

Originally Posted by mynah

Could "little green men" really exist somewhere in the universe, if not on Mars? Why has no multicellular photosynthetic organism capable of independent movement evolved on earth?

Their does exist certain jelly fish that have a symbiosis with photosynthetic algae.


Higher metabolic rates usually means eating the plants for energy.

[Moontanman]

Originally Posted by mynah

Could "little green men" really exist somewhere in the universe, if not on Mars? Why has no multicellular photosynthetic organism capable of independent movement evolved on earth?

The quick answer is that photosynthesis doesn't provide enough energy for a large organism to move around like an animal does. There are, as T-Bird says, various jellyfish that use sunlight for all or nearly all their metabolic needs but they do not require as much energy as a more active land or even water organism needs.

[Galapagos]

For more complex life, what about two or more prehensile appendages? This would seem like an obvious basic, just because it happens to be very useful to be able to move one object relative to another in our universe.