ETs

[Mattevt]

I'm not sure if this is a repost, I couldn't find anything using the search tool.
I'm curious to here peoples thoughts on life out side of our earth. I feel like the general consensus of Christians is that there is no life outside of our own world. However, conversely non-Christians have said that it's ignorant to think that we are the only life-forms in this vast universe. Since we have no hard proof of life outside our own, is this a point for Christianity and creationism?

[Mattevt]

I looked over the links and what I gathered was that they are saying that micro-evolution ads up over time to Macro evolution...Am I wrong? Please correct me.

What they are teaching in high schools (or at least my 10th grade bio class), is that all life from the simplest form of life...the single celled organisms. The organisms survived in the water. Over (supposedly) millions of years changes were made little by little and eventually our little unicellular organism adapted and became sea life, and over even more time some of the sea life grew legs and walked on to the land. If we all came from the same single organism why are all the living beings so vastly different from each other. How is that humans can share a common (although granted WAY back in time) ancestry with Fish?

Quote:
(we see it everyday in the human race)

I also fail to see what you mean by that, even if you said we see it everyday in drosophila, I still don't understand what you are implying.

What I meant was the differences in skin tone, hair, eye color etc.


Also...like I said before...Our planet seems too perfect to be a random act of the big bang. Any closer to the sun and we'd fry, any farther away...and we'd freeze.

[Bugmaster]

If we all came from the same single organism why are all the living beings so vastly different from each other. How is that humans can share a common (although granted WAY back in time) ancestry with Fish?

That's weird -- I got a completely different perception from my high school bio classes. All life on Earth is remarkably similar. All life consists of the same building blocks -- DNA, RNA, proteins, etc. Complex organisms are made up of cells, and these cells are very similar -- they all have membranes, nuclei, etc. Simpler organisms, such as bacteria, lack some of these more advanced features (such as the nucleus), but there are intermediate stages (such as the Volvox colony) that demonstrate how simple cells could clump together to produce something more complex. It definitely seems to me that all life on Earth is related, and evolution provides the best explanation of this relationship that I've seen.

Also...like I said before...Our planet seems too perfect to be a random act of the big bang. Any closer to the sun and we'd fry, any farther away...and we'd freeze.

This is like saying, "God created California specifically for palm trees. Any colder and they'd freeze, any warmer and they'd wither. California is just perfect !" Well yeah, but if you go a little bit to the north, you start seeing pines; go south, and you see cacti. There's a range of climates in which trees can thrive; similarly, there's a range of environments in which life can thrive. This range is, ultimately, fairly narrow -- life "as we know it" could not exist on Jupiter or Mercury -- but it's not zero. Furthermore, there are at least 200 billion stars in our galaxy alone; if you figure that only one in a billion stars would have habitable planets, then there should be about 200 habitable planets in our galaxy. And I don't even know how many galaxies and star clusters there are in the Universe; I suspect the answer is "an awful lot".

[QED]

This is is a difficult one to stay on topic with, Mattevt has us all waving our hands in the air going "I know! I know"

Regarding the topic he started there is another thread which explores the question of our ability to detect ET.
I wrote this in that particular thread to explain why I think we haven't found any evidence yet. Basically, if our example is anything to go by, technology progresses rapidly once a civilization gets to the point where they develop electronics. In the short time since radio was invented we've turned from using high-power omnidirectional broadcasts to more discrete (and efficient) methods like direct satellite and cellular systems. Therefore, a civilization might only be visible in the RF spectrum for 100 years. The chances of two civilizations separated by tens to millions of light-years actually being 'on channel' to share this event are for all practical purposes zero. Which is exactly what we've found so far.

As for the "I'm happy with macroevolution, but don't believe it could lead to macroevolution" this really deserves it's own topic. It's very clear to me how, given the timescales of the Earth and the slow separation of its continents, we end up with the diversity of life we see today along with the vast catalogue of past extinctions. Our observations match the predictions of evolutionary theory precisely. But I don't consider evolution to be 'my subject' so would rather someone else start a topic along these lines (or have I already missed a topic aimed directly at the micro/macro issue?). I seem to recall discussions about a beetle that was introduced from Europe to the Americas which underwent so much change in their respective habitats that specimens from both continents can no longer interbreed - the very essence of speciation.

[harvey1]

Harv: Are you replying to my post? It isn't clear that you are. Did you quote the wrong text by any chance?

Yes, I was. I just take exception to that often used phrase since it has always struck me as false. In any case, I decided to start a thread on it, so I'll respond to that post where you made your reply in that thread.

[Nyril]

If we all came from the same single organism why are all the living beings so vastly different from each other.

Lets stop and think about this statement Mattevt.

Among almost all animals you find a pattern. 2 arms, 2 legs, a tail like thing (we have ours, its called a coccyx). The neck has 7 bones (even the giraffe has 7).

Plants tend to use cholorophil. Fish tend to be alike, occasionally you get the extremely odd one like the lateran fish or the archer fish but again, this fits the pattern of mutation of a common stock.

Are we all really so different?

[Mattevt]

Are you saying fish are not animals? I don't believe we are at all like fish.

I still maintain a belief that it is a little far-fetched to say that humans are related to sloths and armadillos.

[Bugmaster]

Are you saying fish are not animals? I don't believe we are at all like fish. I still maintain a belief that it is a little far-fetched to say that humans are related to sloths and armadillos.

Would it be easier to believe that birds descended from dinosaurs ? Because it looks like they did, you know.

Anyway, there's nothing really special about humans, from the biological point of view; it puzzles me why people find common descent so difficult to accept.

Humans and sloths have many features in common. Both of us have bilateral symmetry. Both are covered in hair (though sloths are much more hairy, obviously). We have fingers and toes, a spine, a brain, a nervous system, one heart... most of the internal organs are very similar. On the microscopic level, our cells are made from the same materials, and they follow the same pattern: membrane, nucleus, mitochondria, DNA/RNA, etc.

It definitely seems to me that we are related through a common ancestor.

[Mattevt]

A dog, a wolf and a fox are decendents from a common ancestor.

Humans and sloths have many features in common. Both of us have bilateral symmetry. Both are covered in hair (though sloths are much more hairy, obviously). We have fingers and toes, a spine, a brain, a nervous system, one heart... most of the internal organs are very similar. On the microscopic level, our cells are made from the same materials, and they follow the same pattern: membrane, nucleus, mitochondria, DNA/RNA, etc

How would moving, thinking organism survive with out these? If the point of evolution is to weed out the weaker organisms then why is it neccessary for variety and diversity? Why doesn't one set of species continue to make itself better and better and better. Why change into many species?

[Bugmaster]

A dog, a wolf and a fox are decendents from a common ancestor.

Ok, so why not a human and an ape ? Or a human and a chicken ?

How would moving, thinking organism survive with out these?

Oh, there are a variety of ways. Plants, for example, have different cellular makeups than we do. Some plants do move (Venus Flytraps being the most spectacular). On the other hand, some animals do not think any more than palnts do (worms and insects come to mind).

If the point of evolution is to weed out the weaker organisms...

Evolution doesn't actually have a point; this is like saying, "the point of gravity is to make things fall down". Gravity is just a natural mechanism by which things fall down; similarly, evolution is a mechanism by which populations change their genetic makeups based on their environment.

then why is it neccessary for variety and diversity? Why doesn't one set of species continue to make itself better and better and better. Why change into many species?

Because of the variety of the environments on Earth. For example, a species of moths that lives in a birch forest might slowly evolve bright white coloration (birch bark is white), because moths that stand out get eaten before they have a chance to reproduce. However, if some of the moths happen to move to a forest with darker trees, the trend would be reversed: darker moths would survive, and brighter moths would be eaten.

So, now we have white moths in one place, and black moths in another. None of them are "best", per se; they're just adapted to their environments.

Small changes like these can happen fairly quickly (geologically speaking). Bigger changes may take more time to occur; for example, a rapidly cooling climate (caused by an asteroid impact) would cause large, cold-blooded animals to die off, while allowing smaller, warm-blooded mammals (as well as dinosaurs who were better insulated by feathers) to survive and reproduce.

[QED]

If the point of evolution is to weed out the weaker organisms then why is it neccessary for variety and diversity? Why doesn't one set of species continue to make itself better and better and better. Why change into many species?

Ask the Irish. The monoculture that led to the potato famine is a classic example of the need for diversity. But diversity is a natural product of evolution (thank goodness ) As members of a species wander off in different directions and become isolated from each other, the aggregation of genetic changes leads to the eventual inability to interbreed when reunited. But it also creates a barrier to pathogens which can only spread rapidly in organisms similar to the ones they've adapted to.

Your view about evolution "weeding out the weaker organisms" seems laced with a little bit of creationists rhetoric -- allusions to nasty goings-on in the woodshed. There is no denying that life is in a constant dance with death but one has to get evolution in perspective: it's not deliberately driven by some bloodthirsty demon! The principle of things making copies of themselves without 100% fidelity is really what evolution is all about. The rest "just happens" as a logical consequence. If this doesn't make any sense to you please ask -- I've left out an awful lot of detail to keep things on the same level as the rest of this discussion -- which I've just noticed is about ETs!