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Author Topic:   What type of biological life will more than likely be found on other planets?
New Cat's Eye
Inactive Member


Message 116 of 178 (670967)
08-21-2012 11:55 AM
Reply to: Message 115 by jar
08-21-2012 11:05 AM


Re: Rare sapience
Could hominids have gotten clothing and fire without intelligence?

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 Message 115 by jar, posted 08-21-2012 11:05 AM jar has responded

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New Cat's Eye
Inactive Member


Message 117 of 178 (670973)
08-21-2012 12:01 PM
Reply to: Message 1 by onifre
08-14-2012 2:34 PM


Now, we can definitely debate my position, but, what I'd like to talk about would be, what traits, if any, would be realistically favored in a biological system?

I think things that evolved early and then stayed forever are things we can expect to find in other highly evolved species. For example, bilateral symmetry. I think we could expect highly evolved aliens to look similiar to life on our planet in that regard.


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New Cat's Eye
Inactive Member


Message 122 of 178 (670990)
08-21-2012 1:00 PM
Reply to: Message 120 by Theodoric
08-21-2012 12:27 PM


Re: bilateral symmetry
I tend to highly agree with this statement, but as I thought about it more I am not so sure.

My thoughts are that we do not know what we don't know. If the life evolved on a planet similar to ours I think this is very likely.

Even though its a bit of a misnomer, I added that "highly" evolved qualifier to supply some implicit assumptions that we're dealing with an environment that would foster a lot of change in the inhabiting species. It'd be a bland discussion to consider a planet where only simple bacteria evolved. I assumed we're more along the Star Trek line here where we're talking about species that would be interesting to us as humanoids.

But there is the rub. We have no idea of what alien life could be like. Is bilateral symmetry a result of unique circumstances in the evolution of life on this planet?

I think that bilateral symmetry did evoke an important advantage that has been utelized ever sense it emerged. I don't think there are any species that subsequently lost it. And, again considering things that would be interesting to us as humanoids, almost all of the Animals exhibit bilateral symmetry.

I think there is a very high likelihood that other life out there exhibits bilateral symmetry, but am very open to the idea that we may find something that utterly astounds us and falls completely outside of any of our expectations.

See, I just don't thing we find some really wacky alien that lacked any symmetry and was just totally bizarre in that regard (at least, talking about something on par with the Animal clade). I'd expect symmetry.

To put it simply, with the knowledge we have I think you are correct. It is what we don't know that is the wild card.

Sure, but what kind of enviroment could exist that would favor assymetry and still push towards something like Animals?


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Replies to this message:
 Message 123 by Theodoric, posted 08-21-2012 1:12 PM New Cat's Eye has responded
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New Cat's Eye
Inactive Member


Message 124 of 178 (670993)
08-21-2012 1:14 PM
Reply to: Message 121 by jar
08-21-2012 12:32 PM


You're just wasting time and bandwidth by limiting it to one step per post. You can make multiples steps per post and still maintain the slow progress of a step by step discussion be going like this:

If you accept "A"
And you accept "B"
and you accept "C"

Then we can conclude "Z".

That way, the responder can just interject wherever they disagree, either A B or C, and you can move right along with the discussion. That's way better than limiting it to a single step per post, which doesn't provide any benefit over that anyways, as it avoids wasting time and space.


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New Cat's Eye
Inactive Member


Message 126 of 178 (670995)
08-21-2012 1:22 PM
Reply to: Message 123 by Theodoric
08-21-2012 1:12 PM


Re: bilateral symmetry
Don't you think this is because of the bias you have from the world you live on and the life you see around you?

Its based on my understanding of how life evolves and how environments impact that evolution.

I would expect symmetry also because that is how we know and expect life to be, but would not be surprised if there was life that did not exhibit bilateral symmetry.

I don't doubt that there will be other types of symmetry, and even species that are assymetrical, but I thinks its likely that the kinds of species that are interesting for this kind of discussion, i.e. Animal-like ones, will exhibit specifically bilateral symmetry.

That is my point. We do not know what we don't know. Until we actually have contact with alien life, we have no idea what the circumstances are of its evolution. We can imagine lots of scenarios and there are a lot of scenarios we would not imagine, because there maybe some things out there outside our ability to currently imagine.

Sure, its possible. But the kinds of enviroments that foster the kind of evolutionary change required for Animal-like species to emerge would also favor bilateral symmetry, in my opinion. We can get into the specifics of the reasons for my opinion, which deal with the early evolution of eukaryotes, but I'm gonna go get some lunch right now.


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New Cat's Eye
Inactive Member


Message 147 of 178 (671135)
08-22-2012 2:15 PM
Reply to: Message 128 by Blue Jay
08-21-2012 1:33 PM


Re: bilateral symmetry
Echinoderms reverted to radial symmetry: the larvae are still bilateral, but the right side is absorbed back into the animal, and the left side develops into the radial animal we know (starfish, sea urchin, etc).

Neat! But wow, I hadn't realized how far back bi-sym went! Its before deutero/proto-stomia!

Apparently that part of my rationale is wrong, but I think the overall point has some staying power - that something that happens so early, and becomes so prevalent, is something that we can expect to happen in similiar environments on other planets.


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New Cat's Eye
Inactive Member


Message 173 of 178 (671228)
08-23-2012 11:21 AM
Reply to: Message 171 by caffeine
08-23-2012 9:19 AM


Re: emergent property?
The question isn't whether intelligence as such will arise. The question is whether intelligence that gives rise to something we would recognise as a technological civilisation will arise. I think that intelligence in the form of problem-solving abilities and social cunning might well be an expected outcome of animal-like life; but it might require a very contingent and specific set of circumstances to lead to an organism which builds things similar to us.

I agree. If we find aliens that are on par with ourselves, then they're going to have come from an environment similiar to ours, and then, I think they're going to look a fair amount like us as well, i.e. symmetric, mobile, dexterous, intelligent...

I don't think science fiction like Star Wars and Star Trek are that far off with there being several types of humanoids with varying degrees of differences from "human".


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