Score Another Point For Evolution

[Biggles7268]

http://news.bbc.co.uk/2/hi/science/nature/5036618.stm

[Antlerman]

This is too cool! It's like a living time capsule taking us back 5 million years! I like this observation:

 

They have lost their eyes over the course of evolution in the gloom of the cave

Maybe eyes aren't as special of a creation as the ID folks would have us to believe? Maybe this is just a plant by Intelligent Designer to test our faith?

[Guest JP]

That would be the fundy response, at least. You know that fossils are really just decoys put there by Satan.

[Ouroboros]

The Satan's decoy theory is interesting, since it means that Satan can create life too. Why does he needs to have demons possess people when he just can create infinite number of pigs and possess them as much as he wants?

[Reverend AtheiStar]

http://news.bbc.co.uk/2/hi/science/nature/5036618.stm

 

That seems to be a very common occurence with cave animals. Their eyes all devolve as does any trace of skin coloring. Quite interesting. It doesn't really seem like natural selection, though. It seems automatic. This leads me to believe that are evolutionary forces that have not yet been discovered. A sort of toolkit that resides within every animal akin to an immune system. Maybe I'm way off base, but that's just what these occurrences make me think of.

 

I was reading Ancestors Tale today (I've been skipping around it slowly) and Dawkins was talking about the Dodo bird and how it started out a flighted pigeon -- genetic analysis of some remaining mitochondia within bone fragments have proven this. Would this be a case akin to cave animals? Or would it be natural selection favoring, for whatever reason, a bird that lost the ability to fly? We know that the absense of predators on their island contributed, but what selective advantage would weaker chest muscles and flightless wings be? Just curious and hoping I could get some feedback.

[Ouroboros]

I don't think there's any "force" per se, that makes something de-evolve. I think it's more a question of cost/benefit, that if too much energy and genetic codes go to vestigial body parts or functions, it eventually becomes lost in a random mutation. Since there's no difference between a seeing creature and a blind in this cave, the creature that's blind might have the benefit of using more matter/energy/brain to hearing, touch and smell, and will win because of that. The seeing creature doesn't sense as much of its vicinity.

[Reverend AtheiStar]

I don't think there's any "force" per se, that makes something de-evolve. I think it's more a question of cost/benefit, that if too much energy and genetic codes go to vestigial body parts or functions, it eventually becomes lost in a random mutation. Since there's no difference between a seeing creature and a blind in this cave, the creature that's blind might have the benefit of using more matter/energy/brain to hearing, touch and smell, and will win because of that. The seeing creature doesn't sense as much of its vicinity.

 

 

I immediately regretted using that word. lol... I can actually think of a pathway that would promote this type of change. I've read that eyes, if not exposed to light, just won't develop. I would think that the skin coloring would follow suit, as well. After many generations of this perhaps it would be genetically coded. Dawkins talked about something similar to this in AT in reference to the upside down catfish and it evolutionary pathway, and supposed it could be a case in point of the Baldwin Effect whereby which a learned behavior became coded over time.

 

Your hypothesis is good, too, though. It makes sense, as well. With no way to know whether or not something is being lost, there's absolutley no way to select for or against it. It would, also, definitley be a waste of resources to have eyes when other sensory systems would need the spare energy. I can actually see (pardon the pun) the advantage a blind creature would have over a sighted if the extra went somewhere else. I'm still struck by the sense of it being automatic, though. It's most likely an illusion, but I can't shake the notion. I wish there was a way to know now. I hate waiting for science to catch up to my expectations of it! lol...

[Ouroboros]

You know there are also the possibility that the eye genetically is coded the way (like you hint there) that if not used it will be de-activated quite fast. I kind of remember there are examples of that when it comes to other functions/instinct behavior etc. Like a hidden switch that turns on/off depending on environment. It might be possible that when these white-cave-critters would be kept in daylight, their offspring in a few generations have eyes again, only because the gene is dormant only, and not really de-evolved!

[Reverend AtheiStar]

I don't think there's any "force" per se, that makes something de-evolve. I think it's more a question of cost/benefit, that if too much energy and genetic codes go to vestigial body parts or functions, it eventually becomes lost in a random mutation. Since there's no difference between a seeing creature and a blind in this cave, the creature that's blind might have the benefit of using more matter/energy/brain to hearing, touch and smell, and will win because of that. The seeing creature doesn't sense as much of its vicinity.

 

It reminds me of the star nosed mole. It's eyes are practically vestigial. But what it has lost in sight it has made up with the other senses! Scientists have mapped out the areas of it's brain devoted to the different parts of it's body. The fleshy tentacles surrounding its nose take the lion's share of its brain's nerve connections! It really does "see" with these things! Dawkins made the suggestion that it might "see" in color just as our eyes do as it takes up comparable brain space. Whatever the pathway, evolution constantly amazes me! How could religion, even with all its mythology, ever compare with the strange beauty of reality?

 

You know there are also the possibility that the eye genetically is coded the way (like you hint there) that if not used it will be de-activated quite fast. I kind of remember there are examples of that when it comes to other functions/instinct behavior etc. Like a hidden switch that turns on/off depending on environment. It might be possible that when these white-cave-critters would be kept in daylight, their offspring in a few generations have eyes again, only because the gene is dormant only, and not really de-evolved!

 

Yes! Quite an exciting thought, huh? It makes we want to go out an get some blind cave fish. They have them down at the pet store. There are eyes are still there, kind of. They just all malformed and under the skin.

 

Check out this quote:

 

http://freshaquarium.about.com/cs/characin...indcavefish.htm

 

"Recently, studies have been conducted to see if eye development could be stimulated. Surprisingly, when lenses from sighted fish were transplanted to the Blind Cave fish, it began to develop an eye. It is hoped that further study of this phenomenon may prove useful in treating blindness in humans."

[redneck22]

http://news.bbc.co.uk/2/hi/science/nature/5036618.stm

 

That seems to be a very common occurence with cave animals. Their eyes all devolve as does any trace of skin coloring. Quite interesting. It doesn't really seem like natural selection, though. It seems automatic. This leads me to believe that are evolutionary forces that have not yet been discovered. A sort of toolkit that resides within every animal akin to an immune system. Maybe I'm way off base, but that's just what these occurrences make me think of.

 

I was reading Ancestors Tale today (I've been skipping around it slowly) and Dawkins was talking about the Dodo bird and how it started out a flighted pigeon -- genetic analysis of some remaining mitochondia within bone fragments have proven this. Would this be a case akin to cave animals? Or would it be natural selection favoring, for whatever reason, a bird that lost the ability to fly? We know that the absense of predators on their island contributed, but what selective advantage would weaker chest muscles and flightless wings be? Just curious and hoping I could get some feedback.

 

 

 

To me they just look like yabbies

[white_raven23]

To me they just look like yabbies

 

So?

 

I suppose it doesn't matter that the cavefish was discovered in a sealed off cave in Israel, and yabbies are Australian?

 

Or that yabbies can be 2oz. to ten pounds, while the cavefish is the picture is clearly in a petrie dish.

 

Your saying that the cave fish and you yabby look alike is much like saying goldfish and koi fish look alike.

[Biggles7268]

actually if you look at them both side by side, they are very much different. shape of the torso, shape of the claws, lack of eyes on one, shape of the tail, size and color. alligators look more like crocodiles than those look like yabbies.

[Ouroboros]

I read somewhere that they did test the DNA on them too, and it is different from other "species".

[HuaiDan]

What's a yabbie? A crawdad?

[sonofspong]

I think yabbie is Australian for crawdad. Crazy Aussies.

 

Anyway, as some of you have stated, if one of your senses was to lose its stimuli, it would deteriorate pretty quickly...to the point that your decendants wouldn't even develope that sensory organ if the lack of stimuli continued. Cave creatures almost always have no eyes; they dont need them anymore, its just useless organ in that enviroment.

 

Imagine if a group of humans built a large space ship, and lived on it...in zero-g...for the rest of thier lives. Thier muscles would deteriorate, bone density would lessen, because of the lack of stimuli (gravity) to keep those muscles strong.

 

Their descendants would evolve over time to better adapt to that zero-g enviroment. Perhaps they would have more flexible, or even jelly-like limbs, to take advantage of zero-g's features. maybe they would have adhesive substance on thier hands and feet to better stick to surfaces. Who knows.

[Reverend AtheiStar]

I think yabbie is Australian for crawdad. Crazy Aussies.

 

Anyway, as some of you have stated, if one of your senses was to lose its stimuli, it would deteriorate pretty quickly...to the point that your decendants wouldn't even develope that sensory organ if the lack of stimuli continued. Cave creatures almost always have no eyes; they dont need them anymore, its just useless organ in that enviroment.

 

Imagine if a group of humans built a large space ship, and lived on it...in zero-g...for the rest of thier lives. Thier muscles would deteriorate, bone density would lessen, because of the lack of stimuli (gravity) to keep those muscles strong.

 

Their descendants would evolve over time to better adapt to that zero-g enviroment. Perhaps they would have more flexible, or even jelly-like limbs, to take advantage of zero-g's features. maybe they would have adhesive substance on thier hands and feet to better stick to surfaces. Who knows.

 

It would be a very interesting experiment, to say the least!

[HuaiDan]

Anyway, as some of you have stated, if one of your senses was to lose its stimuli, it would deteriorate pretty quickly...to the point that your decendants wouldn't even develope that sensory organ if the lack of stimuli continued.

 

Careful!!!!! That's Lamarckian speculation. Adaptation the occurs within the lifetime of an individual does not bear directly on adaptation that occurs across generations. The former is physiological, the latter is genetic. It's like saying giraffes acquired a long neck through a lifetime of stretching to reach the topmost leaves. What actually happened was that the giraffes with shorter necks went hungrier than the giraffes with the longer ones and didn't do as well in producing offspring.

[scitsofreaky]

Anyway, as some of you have stated, if one of your senses was to lose its stimuli, it would deteriorate pretty quickly...to the point that your decendants wouldn't even develope that sensory organ if the lack of stimuli continued.

 

Careful!!!!! That's Lamarckian speculation. Adaptation the occurs within the lifetime of an individual does not bear directly on adaptation that occurs across generations. The former is physiological, the latter is genetic. It's like saying giraffes acquired a long neck through a lifetime of stretching to reach the topmost leaves. What actually happened was that the giraffes with shorter necks went hungrier than the giraffes with the longer ones and didn't do as well in producing offspring.

I think that could be attributed to either the baldwin effect or gene assimilation/accomidation(?) (not sure about this one since I am just now learning about it). In my understanding, the baldwin effect is that parents (can) pass on the capacity to change easily. As for gene assimilation, see my post that has some about it and some links about it, which I am still reading.

[Reverend AtheiStar]

Anyway, as some of you have stated, if one of your senses was to lose its stimuli, it would deteriorate pretty quickly...to the point that your decendants wouldn't even develope that sensory organ if the lack of stimuli continued.

 

Careful!!!!! That's Lamarckian speculation. Adaptation the occurs within the lifetime of an individual does not bear directly on adaptation that occurs across generations. The former is physiological, the latter is genetic. It's like saying giraffes acquired a long neck through a lifetime of stretching to reach the topmost leaves. What actually happened was that the giraffes with shorter necks went hungrier than the giraffes with the longer ones and didn't do as well in producing offspring.

 

I agree that giraffe's stretching is a silly way to look at evolution, but it makes sense that within an environment of total darkness you would witness a change in the organs that need light to start up. Eyes, without light, fail to develop. Without sunlight as a trigger, no melanin develops. If conditions were constant over many generations you should witness a genetic change. I believe this is what we see within cave animals which are usually blind and without pigment. Natural selection is but one pathway to evolutionary change.

 

 

Anyway, as some of you have stated, if one of your senses was to lose its stimuli, it would deteriorate pretty quickly...to the point that your decendants wouldn't even develope that sensory organ if the lack of stimuli continued.

 

Careful!!!!! That's Lamarckian speculation. Adaptation the occurs within the lifetime of an individual does not bear directly on adaptation that occurs across generations. The former is physiological, the latter is genetic. It's like saying giraffes acquired a long neck through a lifetime of stretching to reach the topmost leaves. What actually happened was that the giraffes with shorter necks went hungrier than the giraffes with the longer ones and didn't do as well in producing offspring.

I think that could be attributed to either the baldwin effect or gene assimilation/accomidation(?) (not sure about this one since I am just now learning about it). In my understanding, the baldwin effect is that parents (can) pass on the capacity to change easily. As for gene assimilation, see my post that has some about it and some links about it, which I am still reading.

 

Here's a paper that tries to explain this ubiquitous phenomenon:

 

https://kb.osu.edu/dspace/bitstream/1811/50.../V64N03_221.pdf

[Young Mother Atheist]

I would agree with HuaiDan. You have to be careful in thinking about this topic. Traits, organs, genes, are only passed down by DNA- the instructions. These cannot be altered by a living creature's habits changing. Once that creature is made, it is made by the instructions (DNA) that it has. Mutations can occur when a new creature is made- that's part of natural selection.

 

Make sure any theory you read or consider keeps in mind that DNA are instructions that cannot be changed once they are active in an individual.

 

Good thread!

[nick5]

Imagine if a group of humans built a large space ship, and lived on it...in zero-g...for the rest of thier lives. Thier muscles would deteriorate, bone density would lessen, because of the lack of stimuli (gravity) to keep those muscles strong.

Yes! Reminds me of that SF book I read a while ago (forgot the title). Humans had colonized the moon and the second generation moon people had much lighter bone structure and weaker muscles. They also looked younger because the weaker gravity didn't pull their features down as much as Earth's people.

[Young Mother Atheist]

Imagine if a group of humans built a large space ship, and lived on it...in zero-g...for the rest of thier lives. Thier muscles would deteriorate, bone density would lessen, because of the lack of stimuli (gravity) to keep those muscles strong.

 

Let me point out here, just to make sure we all understand. They would only develop anything to adjust to life in space IF there was a mutation in their DNA given to their offspring that favored survival in the different environment. Their offspring (if they could survive to have any, what with their bodies falling apart from lack of gravity) wouldn't just develop the neccessary bodily changes to live in space.

Most likely they would all just die before being able to adapt because the mutation likely wouldn't happen in time or in enough people...plus this would have to be a LARGE SCALE group of humans for this to even be possible.

[LadyFeline]

Imagine if a group of humans built a large space ship, and lived on it...in zero-g...for the rest of thier lives. Thier muscles would deteriorate, bone density would lessen, because of the lack of stimuli (gravity) to keep those muscles strong.

 

Let me point out here, just to make sure we all understand. They would only develop anything to adjust to life in space IF there was a mutation in their DNA given to their offspring that favored survival in the different environment. Their offspring (if they could survive to have any, what with their bodies falling apart from lack of gravity) wouldn't just develop the neccessary bodily changes to live in space.

Most likely they would all just die before being able to adapt because the mutation likely wouldn't happen in time or in enough people...plus this would have to be a LARGE SCALE group of humans for this to even be possible.

...You really have NO idea how that kind of natural selection works, do you?

 

When you transplant an organism into a different, but surviveable, environment (such as zero-G, since we don't need gravity to survive - otherwise, we wouldn't be able to survive in a zero-G environment. Like, oh, the space station...) it has nothing to do with how "quickly you mutate" to survive. Mutations wouldn't be needed right away.

 

Instead, the process would be gradual, becoming more pronounced in our offspring (and, yes, things can reproduce and live out their lives in zero-G. We proved that on the Mir) and human physiology adapted to make the most of the new environment. Their muscles wouldn't need to be as dense as ours. Their bones wouldn't need to be as rigid. Their organs wouldn't need to work as hard. So, in order to be more efficient, their bodies, from birth onward, simply wouldn't expend as much energy on those things. Instead, that unused energy would likely be used by the brain, since it's a high-maintenance organ, anyway.

 

You wouldn't need a large population to see these changes, either. Since it has nothing at all to do with random mutations, you can see this process occurring in people who travel in space now. Even a few months on the space station results in atrophying muscles and loss of bone density. It's nothing fatal. It's simply a matter of rerouting energy usage - something that our bodies would do from the very beginning, if we were to be born in a low- to zero-G environ.

 

(By the way, get your facts straight. "Zero-G" is not synonymous with "space". Zero-G does not entail a vacuum, and a simple lack of gravity wouldn't cause our bodies to "fall apart")

[Young Mother Atheist]

My mistake, I thought we were talking about an actual change in the DNA of humans. It would be possible, then, to just have changes occur in the adults and then the children would just develop differently based on the environment.

 

Sorry I misunderstood. I thought were talking about genetics so I assumed that example to be referring to a DNA change.

 

Thanks!