Evolution: ask your questions here

[lunamoth]

Interesting. I don't know, which will not prevent me from commenting and speculating. First, are plants possibly dominant, if not sentient? What I mean is, if you add up all the biomass on the planet, I'm guessing most of it is plant, rather than animal.

But maybe you're wondering why plants didn't develop sentience, or at least, the same sort of sentience that many animals species have? I'm going to speculate it's because they didn't need to to survive and reproduce. I mean, if your main source of energy is sunlight, maybe you don't need a whole lot of sentience to locate and get it.

But if sentience and mobility confer selective advantage (I can move to the sunnier regions and build technology to help me gather more sun, I can recognize my competition and clobber it), why wouldn't a photosynthetic organism develop these traits?

Fungi are heterotrophs that do just fine with lack of sentience and limited mobility, so its not just the need to eat.

 

[doppelganger]

But if sentience and mobility confer selective advantage (I can move to the sunnier regions and build technology to help me gather more sun, I can recognize my competition and clobber it), why wouldn't a photosynthetic organism develop these traits?

For the simple reason that they were not selected out for not having done so. Or put another way, because it didn't happen and didn't need to happen. Were there a chain of mutations that yielded sentient trees, they might clog out the sunlight for the ones that can't move. But that hasn't happened, so the trees have done just fine without it.

BTW, there is a limited form of "sentience" in some trees associated with the root apices.

 

[lunamoth]

For the simple reason that they were not selected out for not having done so. Or put another way, because it didn't happen and didn't need to happen. Were there a chain of mutations that yielded sentient trees, they might clog out the sunlight for the ones that can't move. But that hasn't happened, so the trees have done just fine without it.

Perhaps, but how do you know that it didn't happen just because, by random chance, it didn't happen? Wind the world back, run the program again, and we might have photosynthetic species with sentience.

BTW, there is a limited form of "sentience" in some trees associated with the root apices.

Very limited.

 

[doppelganger]

Perhaps, but how do you know that it didn't happen just because, by random chance, it didn't happen?

For starters, things don't happen because of "random chance." Once something has or has not been determined to have happened, "chance" and "randomness" have nothing whatsoever to do with inquiry. Those are terms related to probability before an event or condition is determined.

It may have happened and there are secretly hidden sentient trees out there, but as of right now, as you note in your last sentence in response to me, nobody seems to have found anything beyond a very limited sentience in trees and plants, nor any reason why they would need it to survive.

 

[Autodidact]

But if sentience and mobility confer selective advantage (I can move to the sunnier regions and build technology to help me gather more sun, I can recognize my competition and clobber it), why wouldn't a photosynthetic organism develop these traits?

Fungi are heterotrophs that do just fine with lack of sentience and limited mobility, so its not just the need to eat.

Again, I really have no idea, and am just guessing. I'm also guessing that people who know a lot more than me have given this considerable and more valuable thought.

Now you're asking two things, sentience and mobility. First on the sentience, I'm guessing that sunlight is just not in such short supply as an external food source. I know there is some competition for it e.g. in the rain forest, where plants grow taller to try to get their share. I guess they're kind of sentient, as they do grow toward it, and I'm guessing that's all they need to get enough to survive.

As for mobility, it seems like they need roots to get water, but then again if you were mobile you could walk over to the water hole and get it, so I'm not sure about that.

Imagining plants that walk over to water holes certainly seems odd, though, doesn't it?

 

[Wannabe Yogi]

Ever wonder what the Theory of Evolution really says? What evidence it's based on? How science knows it's correct? What its implications are? Ask your questions here, and the knowledgeable members will try to answer them.

Why did the Tyrannosaurus Rex eat only Coconuts on Noah's Ark ?

Is this a real picture of T-Rex hunting for Coconuts ?

Please help me ! I am being told this by a real scientists

http://www.digitaljournal.com/article/177963

 

[lunamoth]

For starters, things don't happen because of "random chance." Once something has or has not been determined to have happened, "chance" and "randomness" have nothing whatsoever to do with inquiry. Those are terms related to probability before an event or condition is determined.

There is an element of randomness and chance in nature, though. Mutations do occur randomly, and these are the source of (ultimately all) genetic variation. I think Autodidact is probably right that there just never was a set of conditions that conferred a strong enough selective advantage toward sentience for plants to 'need' to develop it. However, it also seems like a possibility that things could have taken a different turn and resulted in sentient photosynthetic organisms, even under the same physical conditions.

 

[doppelganger]

There is an element of randomness and chance in nature, though. Mutations do occur randomly, and these are the source of (ultimately all) genetic variation.

Still not "random." Random and chance concern probabilities and prediction. They have to do with how an information system assesses a probability wave. Mutations have causes, which have causes, which have causes. For example, an electron tearing through a zygote to alter some DNA is there as a result of all the movements and interactions of the universe up to the point that it takes it mutating trip through the cell.

However, it also seems like a possibility that things could have taken a different turn and resulted in sentient photosynthetic organisms, even under the same physical conditions.

Sure. But that's like asking, "Why didn't humans evolve laser vision?" or "Why didn't cats evolve wings?" They could have . . . didn't . . . and adapted so far without them.

 

[Wannabe Yogi]

Why did Jesus Ride on the backs of dinosaurs? Was it a faster mode of transportation then a car?

If you science types want to win me and the average american male over to believe in that stuff called Evolution. You better put a lot of time and thought into this type of question.

 

[Autodidact]

Perhaps, but how do you know that it didn't happen just because, by random chance, it didn't happen? Wind the world back, run the program again, and we might have photosynthetic species with sentience.

Yes, maybe. But that gets us into philosophical realms rather than natural science, doesn't it?

Anyway, I can certainly imagine it.

 

[lunamoth]

Again, I really have no idea, and am just guessing. I'm also guessing that people who know a lot more than me have given this considerable and more valuable thought.

Now you're asking two things, sentience and mobility. First on the sentience, I'm guessing that sunlight is just not in such short supply as an external food source. I know there is some competition for it e.g. in the rain forest, where plants grow taller to try to get their share. I guess they're kind of sentient, as they do grow toward it, and I'm guessing that's all they need to get enough to survive.

As for mobility, it seems like they need roots to get water, but then again if you were mobile you could walk over to the water hole and get it, so I'm not sure about that.

Imagining plants that walk over to water holes certainly seems odd, though, doesn't it?

You are right, I added mobility in there too. ;-) Because of cell walls, and well pretty much everything else about plant structure, it would not be efficient for plants to evolve from here to be like animals, with sentience and mobility. So, Ents are not likely to be the future dominant species.

But, if the development of sentience was a selective advantage for heterotrophs, I just don't see how it could not also be a selective advantage for autotrophs.

Sorry for side-tracking your thread. But, thank you for replying and sharing your thoughts about this!

 

[lunamoth]

Still not "random." Random and chance concern probabilities and prediction. They have to do with how an information system assesses a probability wave. Mutations have causes, which have causes, which have causes. For example, an electron tearing through a zygote to alter some DNA is there as a result of all the movements and interactions of the universe up to the point that it takes it mutating trip through the cell.

I'm not saying they are un-caused. The are chaotic and unpredictable. Are you saying that there is intelligence, direction, or meaning behind the events that lead to mutations?

Sure. But that's like asking, "Why didn't humans evolve laser vision?" or "Why didn't cats evolve wings?" They could have . . . didn't . . . and adapted so far without them.

Kind of. I admit I just brought up the question because I was interested in hearing other people's creative thoughts about this.

With respect to your examples there are mammals with wings, birds with wings, and insects with wings - all kinds of examples of convergent evolution. Wings are an advantage for filling certain niches. So, I wonder why we did not see the convergent evolution of photosynthesis in organisms that are more 'animal-like,' or why photosynthetic organisms did not evolve to fill some of the same niches occupied by animals when they have the huge advantage of photosynthesis.

 

[Biblestudent_007]

Do you feel like you have clear understanding of what the Theory of Evolution actually says?

I'm not a expert in the field but generally, yes.

 

[painted wolf]

OOHhh... newhope is play the "like" game again... :jiggy:

if the footprints are "bird-like" then they must be made by "fully formed birds"... therefore any "bird-like" footprints must be made by birds.

Say hello to this bird:

He left lots of bird-like footprints in the late Triassic. So it's only "common sense" that it's a bird.
Thanks for proving dinosaurs are birds newhope!

As for the "mystery" of the Platypus...
1) you don't need to be fully endothermic to need to cool off. Even reptiles risk overheating, evolving something as simple as sweating would be a huge benefit and a good step toward full endothermy.
Plus not that all mammals are good endotherms, many... like the platypus, are very poor at controlling their body temperature. Many reptiles are very good at controlling their body temperatures, crocodiles especially.

2) Because adding lipids to the water slows it's evaporation... cutting down on the work needed from the parent. It's not a difficult concept and it''s not as if it's unique... desert amphibians can do it too.

3) platypus are not the only venomous mammals, venom is common to all vertebrate groups. Plus they also have less advanced fossil ancestors with less developed bills. And the Platypus genome shows it's place in the mammal lineage... not with birds, not with reptiles.

wa:do

 

[doppelganger]

I'm not saying they are un-caused. The are chaotic and unpredictable. Are you saying that there is intelligence, direction, or meaning behind the events that lead to mutations?

No. I am saying they are caused by the causes/effects that preceded them back into infinity. They are not intrinsically "chaotic" or "unpredictable." That is an assessment of the amount of information one has about them before they are determined. Once they occur they are neither chaotic nor unpredictable. They simply are, because they've now been determined.

With respect to your examples there are mammals with wings, birds with wings, and insects with wings - all kinds of examples of convergent evolution. Wings are an advantage for filling certain niches. So, I wonder why we did not see the convergent evolution of photosynthesis in organisms that are more 'animal-like,' or why photosynthetic organisms did not evolve to fill some of the same niches occupied by animals when they have the huge advantage of photosynthesis.

Well, just because something might be more advantageous does not mean that it will occur. Laser vision would be really handy. A cat would have access to all sorts of additional game if it could fly. Trees didn't undergo those changes and they still survive to pass on their DNA. They are what they are and it works for them.

 

[painted wolf]

Kind of. I admit I just brought up the question because I was interested in hearing other people's creative thoughts about this.

With respect to your examples there are mammals with wings, birds with wings, and insects with wings - all kinds of examples of convergent evolution. Wings are an advantage for filling certain niches. So, I wonder why we did not see the convergent evolution of photosynthesis in organisms that are more 'animal-like,' or why photosynthetic organisms did not evolve to fill some of the same niches occupied by animals when they have the huge advantage of photosynthesis.

There are several free living photosynthetic organisms... like euglena.
Several animals exist in symbiotic relationship with photosynthetic organisms like Coral and even a sea slug.
Plants however are limited by their cellular structure... they have stiff cell walls that are great for resisting the pressure of storing the large amount of water they need to photosynthesize. But this limits their ability to live an "active" lifestyle.

If flexible animal like cells tried to store so much water they would explode. The only animals that can photosynthesize are aquatic.

wa:do

ps... plus what advantage is an animal like lifestyle for a plant? What evolutionary pressure is there that would encourage it?

 

[Autodidact]

There are several free living photosynthetic organisms... like euglena.
Several animals exist in symbiotic relationship with photosynthetic organisms like Coral and even a sea slug.
Plants however are limited by their cellular structure... they have stiff cell walls that are great for resisting the pressure of storing the large amount of water they need to photosynthesize. But this limits their ability to live an "active" lifestyle.

If flexible animal like cells tried to store so much water they would explode. The only animals that can photosynthesize are aquatic.

wa:do

ps... plus what advantage is an animal like lifestyle for a plant? What evolutionary pressure is there that would encourage it?

Just as I thought, an actual informed view from someone who knows about the subject. Thanks, painted.

I have a question. How can something that does photosynthesis be an animal? Isn't that the definition of a plant?

 

[lunamoth]

There are several free living photosynthetic organisms... like euglena.
Several animals exist in symbiotic relationship with photosynthetic organisms like Coral and even a sea slug.
Plants however are limited by their cellular structure... they have stiff cell walls that are great for resisting the pressure of storing the large amount of water they need to photosynthesize. But this limits their ability to live an "active" lifestyle.

If flexible animal like cells tried to store so much water they would explode. The only animals that can photosynthesize are aquatic.

wa:do

ps... plus what advantage is an animal like lifestyle for a plant? What evolutionary pressure is there that would encourage it?

Thanks PW. I know there are free living organisms that are photosynthetic, such as Euglena. The original questions was why not sentience for plants? My thought is that the combination of events leading to sentience are so rare that it's amazing it happened once (in the branch leading to animals). As you point out, corals and the sea slugs are in symbiotic relationships with photosynthetic organisms, not photosynthetic themselves.

I'm not sure about your point about needing large amounts of water for photosynthesis. Plants on land require large amounts of water for transpiration and turgor pressure for structure, but I don't think photosynthesis requires more water than an animal's body could hold. After all, isn't the same amount of water proportionally generated by cellular respiration?

Sentience would confer to plants the same advantages it has conferred on animals. Animals do not 'need' sentience, but it emerged because, presumably, it gave animals more adaptability, and more adaptability is an evolutionary advantage.

So, I think it was simply due to chance that there are no sentient plants, or photosynthetic, sentient animals.

This may explain, though, why aliens are green.

 

[lunamoth]

Several animals exist in symbiotic relationship with photosynthetic organisms like Coral and even a sea slug.

Having taken a moment to review a bit about sea slugs (yes, I am seriously procrastinating from other things I should be doing), they look poised to be the basis for the future dominant species in say a couple billion years. If they survive the era of Homo sapiens, that is.

 

[Shadow Wolf]

Well this is partly evolution, but mostly genetics and I have absolutely no idea what the answer is:
Incest produces offspring with genetic mutations and defects by about the third or fourth generation.
Lab rats are essentially genetic clones but do not lack these defects.
My understanding, which is why I'm probably puzzled, is that in both groups they are sharing the same gene pool when producing offspring, so how/why is it one group is doomed to have genetically mutated offspring that may be pretty bad, but the lab rats it seems are without defect which makes them suitable for genetic testing since they are all the same.