A debate on the conseqences of biological evolutionary forces.

In this thread I propose that we explore deep questions emergent from biological evolutionary processes. This is not to be a platform for one "ism" versus another. There are ample threads in that regard already. Nor am I suggesting a probing of the validity of evolution or its counter, there are threads for that, too. As such, I imagine that this will depend heavily on the beliefs of contributors. Please do not become upset if there are views different from yours. This was to be expected from the outset. Instead I ask that you "agree to disagree" and clearly state the reasons for your objections in a dispassionate and gentle manner. Simple unexplained statements of opinion are not really wanted. Make your argument/s as reasonable, rational and forceful as you can, without getting lost in emotion.

Now, what I am proposing is NOT that we look backwards into time, but that we speculate about what may yet be, entirely hypothetically (although if you have scientific supporting evidence, I encourage you to post it).

I'll start by providing an observation and some questions arising from it:

To me, by observation, it appears that there has been an overall 'direction' of life processes towards biological complexity, functional efficiency and integration with existing lifeforms. Yet in a stochastically neutral environment, it should be expected that there would be equal movement contrary to those concepts. For the purposes of this discussion, I'll call this 'devolution'. Do you know of devolutionary examples and, if there are such devolutions, why are they not as equally apparent as evolutionary ones?

Is my impression valid or is it based upon psychological filtering (or some other mechanism)? How might such filtering work? How does such filtering of what we observe, arise?

I am intellectually aware that evolutionary models do not accommodate any overall "directive" forces, so why might this impression of a direction be so strong?

Complexity is not a requirement for evolution - so "devolution" would be a hard concept to pin down. And nature isn't exactly a stochastic environment - mutations that help survival and/or reproduction, "more" complex or "less" complex, will be passed on more often, and disseminate into a population. Mutations might be random, but their dissemination into a population is not.

Howdy,

I'm afraid I'm a bit confused by what you are asking for. Are you asking for examples of "devolution" in what seem to be stable environments? In other words, an apparent loss of some complexity in a stable environment? If that is the case, such is still consistent with evolutionary theory, but I can provide an example of something like that.

In the devonian, during the widening of the Atlantic ocean, species of phacopid trilobites (which had complex multi-faceted eyes) became separated populations (to be clear, some phacopid populations existed on what might now be the Eastern US margin while another population lived in what is now the Atlas mountains of Morocco.) The eroding mountains of the Eastern US created an ecosystem with muddy waters with increased sediments (as observed in the rocks), but the Moroccan environment did not see as much sediment (didn't have as much erosion). In this case, the phacopid trilobites of the Eastern US lost eye facets (lenses) in comparison to those of the other Moroccan population.

This is an example of a "loss of complexity," and if that is what you mean by "devolution,"then I hope that helps.

Although I certainly agree, there seem to be directive forces controlling the change (in this example separation of populations via a widening Atlantic ocean where two different environments favored different members of those populations).

Sincere regards,
Hydeman

originally posted by: Syyth007
Complexity is not a requirement for evolution - so "devolution" would be a hard concept to pin down. And nature isn't exactly a stochastic environment - mutations that help survival and/or reproduction, "more" complex or "less" complex, will be passed on more often, and disseminate into a population. Mutations might be random, but their dissemination into a population is not.

Let us consider that we say that multicellular organisms have arisen from single cellular organisms.

Surely, then, single cellular organisms have also arisen from multicellular ones and this will have occurred with nearly the frequency that multicellular have arisen from unicellular.

In fact, with this mix of up and down cellularity, how would one determine which way any particular species may have arisen, or in what combinations?

originally posted by: hydeman11
Howdy,

I'm afraid I'm a bit confused by what you are asking for. Are you asking for examples of "devolution" in what seem to be stable environments? In other words, an apparent loss of some complexity in a stable environment? If that is the case, such is still consistent with evolutionary theory, but I can provide an example of something like that.

In the devonian, during the widening of the Atlantic ocean, species of phacopid trilobites (which had complex multi-faceted eyes) became separated populations (to be clear, some phacopid populations existed on what might now be the Eastern US margin while another population lived in what is now the Atlas mountains of Morocco.) The eroding mountains of the Eastern US created an ecosystem with muddy waters with increased sediments (as observed in the rocks), but the Moroccan environment did not see as much sediment (didn't have as much erosion). In this case, the phacopid trilobites of the Eastern US lost eye facets (lenses) in comparison to those of the other Moroccan population.

This is an example of a "loss of complexity," and if that is what you mean by "devolution,"then I hope that helps.

Although I certainly agree, there seem to be directive forces controlling the change (in this example separation of populations via a widening Atlantic ocean where two different environments favored different members of those populations).

Sincere regards,
Hydeman

Your contribution is exactly what I would describe as an example of devolution, and indicates that such does occur. Yet somehow, the overall 'big picture' is evolutional.

Can you see where I am going with this. Why don't we see more of this kind of thing. Is it a fault in the way we perceive things or is there a fundamental reason?

a reply to: chr0naut

Howdy,

If that is what you are looking for, I could see some potential reasons for difficulty in finding the evidence you seek. Cellular organisms do not preserve well in the rock record, so morphological determinations of species would be difficult. Even then, genomic evidence would be the best information, and genes certainly do not preserve to well in rocks.

I don't know why you believe multicellular organisms should evolve into unicellular organisms at "nearly the same frequency" as the other way around (nor do I see any means to quantify the frequency of which multicellular organisms evolved from unicellular organisms... presumably, it only needed to happen once if life has common ancestry, right?) That said, the conditions in which single celled organisms presumably evolved into multicellular organisms was a period in which there was no competition for such multicellular organisms. In the modern world, there exist single celled organisms to compete with any "devolved" unicellular organisms. The niche is already filled.

That said, there has been a rather interesting (but fruitless, by my untrained opinion) argument for HeLa cells being designated a unique species.
en.wikipedia.org...

Of course, all of this falls under the mainstream viewpoint covered by evolutionary theory, so I understand if you don't agree. If that is the case, I suppose I would appreciate further clarification as to why you think life should change with the same frequency from multicellular to unicellular as from unicellular to multicellular. Also, I would be curious if anyone here could further clarify how often multicellularity has arisen.

Sincere regards,
Hydeman

In response to your above question, I do believe it is a problem of misinterpreting evolutionary theory. Evolution has no desired end goal of complexity. Evolution is a response to changes in environmental conditions, more than anything. If you look for an endless striving for complexity under the theory of evolution, of course you will not find it. There are other examples, I'm sure. I picked phacopid trilobites because I collect them. Perhaps a more familiar example would be vestigial organs, like the appendix.

a reply to: chr0naut

We have an idea that lifeforms evolved from non-complex to complex forms from the fossil record - but the reason devolution doesn't occur more often, is because the established population that branched off from a less complex population usually has better genetic viability, and usually, those two populations compete for resources - the population that can survive longer, and breed more successfully wins, and will out breed and dominate other populations.

Complexity compounds over time, but complexity doesn't always garuntee biological success, but usually, biodiversity in a population spells success, as there are more available avenues for genetic propagation.

I hate to use this example, but we as a species are capable of inflicting a nuclear war on this planet that would kill off most complex lifeforms on this planet - in this situation, genetic complexity wouldn't be a successful trait, and the hardier less complex lifeforms that are established on this planet would still be able to reproduce, while the much more genetically complex lifeforms would die off rather quickly.

a reply to: chr0naut

The body doesn't show the "complexity" of the forces / process.

For example, in the above users post about eyes, the change to the system, that is, the change within the eyes' of trilobites, were added steps, not a loss of steps or complexity.

E.g. If evolution was the process of solving a math problem, 5-1=4 is more complex than 4.

That is, you're trying to measure a process by its outcome, but the process and outcome are separate things. (5-1=4 is not the same as 4.)


but yeah, you make a good point about trying to measure evolution through the body, when it's really the force or spirit which we should be trying to measure.

Why don't we see the eye able to detect other bands of frequency, ultraviolet etc. Evolution should have led to these types of things.
Everything is in decline not evolving better.
One word, entropy.
It means near perfection was long ago and all is devolving.

originally posted by: hydeman11
Howdy,
In the devonian, during the widening of the Atlantic ocean, species of phacopid trilobites (which had complex multi-faceted eyes) became separated populations (to be clear, some phacopid populations existed on what might now be the Eastern US margin while another population lived in what is now the Atlas mountains of Morocco.) The eroding mountains of the Eastern US created an ecosystem with muddy waters with increased sediments (as observed in the rocks), but the Moroccan environment did not see as much sediment (didn't have as much erosion). In this case, the phacopid trilobites of the Eastern US lost eye facets (lenses) in comparison to those of the other Moroccan population.

Correct me if I'm wrong but, didn't the European variety also have similar developments with their eyes as the N. American counter parts? I thought I remembered reading that they were also under the proposed new genus of Eldredgeops like the N. Americans back in the early 90's. I can see why it doesn't really stick though. Phacopid is much easier to say haha

This is an example of a "loss of complexity," and if that is what you mean by "devolution,"then I hope that helps.

But is it really a loss of complexity or is it adaptation to a changing ecological niche? There were several contemporary eye designs for different Trilobites depending on their ecological niche. While there are some excellent specimens available, we can't be sure what other potential adaptations may have occurred that aren't readily demonstrated in the external morphology. Despite the loss of facets, they are still understood to have had excellent 360 degree vision, depth perception(overlapping fields of vision as a result of the massive compound eyes) and possibly even color vision. All hallmarks of schizochroal eyes. They were also taking down prey based on the size of the glabella which contained the majority of their digestive system and it was significant in size compared to the rest of the Devonian Trilobites. They were definitely eating some good sized bits and not just particles like some of the bottom feeding trilobites.

Although I certainly agree, there seem to be directive forces controlling the change (in this example separation of populations via a widening Atlantic ocean where two different environments favored different members of those populations).

I would say this fits in very nicely with everything we know about adaptation to ecological niches. A recent analogy would be the differences between a desert adapted Kit Fox and the aptly named Arctic Fox. I just hate to use the word 'devolution' because there really isn't such a thing as evolution has no direction and doesn't differentiate between forwards and backwards. It just adapts to the situation at hand in order for the organism to survive. Case in point with your example, their niche became significantly different than that of their Moroccan contemporaries because of different localized conditions, murkier water.

I certainly agree with your follow-up post/thought that there is no way to measure for an organism moving from multicellular to single celled as that type of structure simply doesn't preserve well and there is no known analogue that demonstrates it happening.

We would need to be able to demonstrate some sort of scenario where this type of adaptation would benefit the organism. Maybe I'm just being very imaginative at this late hour, but I can't think of a scenario in which this becomes likely.

In response to your query regarding how often multicellular life has arisen, its a hard nut to crack. We've had unicellular organisms for what...3.5bn years now and the first fossilized multicellular structures are around 580 Mn with genetics predicting that multicellular life emerged 600-800Mn years ago. That leaves a heck of a big window open for us with no knowledge. If I were a betting man though, I would place my money on Choanoflagellates as they can exist as both single celled and multicellular organisms. To me, its the logical jumping off point where we can trace the origin of animals back to because they truly are a bridge between those two worlds. Just my 2 cents.

Howdy,

Interesting question with an equally interesting answer. Are you aware bees see in ultraviolet?

www.bbc.com...

Sincere regards,
Hydeman

originally posted by: hydeman11
Howdy,

Interesting question with an equally interesting answer. Are you aware bees see in ultraviolet?

www.bbc.com...

Sincere regards,
Hydeman

And yet we don't.
If we are the pinnacle of evolutionary processes how can that be?

originally posted by: TinfoilTP
Why don't we see the eye able to detect other bands of frequency, ultraviolet etc. Evolution should have led to these types of things.

WE don't but some organisms do see in UV
www.theatlantic.com...

Everything is in decline not evolving better.

What exactly is your frame of reference for that postulation?

One word, entropy.
It means near perfection was long ago and all is devolving.

If the Earth were a closed system sure, but it's not. The Second law of Thermodynamics does not apply to evolution. Additionally, the second law doesn't claim that the entropy of any part of a system increases: if it did, ice would never form and vapor would never condense, since both of those processes involve a decrease of entropy. Rather, the second law says that the total entropy of the whole system must increase. Any decrease of entropy (like the water freezing into ice cubes in your freezer) must be compensated by an increase in entropy elsewhere (the heat released into your kitchen by the refrigerator).

a reply to: TinfoilTP

Who says we are the pinnacle of the evolutionary process? That's a complete misunderstanding of the theory and how it applies to Anthropology. If we were the pinnacle then we would not continue to evolve and nothing else would continue to evolve either.

originally posted by: peter vlar
a reply to: TinfoilTP

Who says we are the pinnacle of the evolutionary process? That's a complete misunderstanding of the theory and how it applies to Anthropology. If we were the pinnacle then we would not continue to evolve and nothing else would continue to evolve either.

What else knows it is nothing but stardust?

a reply to: TinfoilTP

self awareness and knowledge of science doesn't make us the pinnacle of evolution though. It just makes us more knowledgeable than those who came before us. That's you forcing an anthropic principle where it doesn't belong. Physically, Neandertal and in some ways, Homo Erectus were superior to the humans walking the Earth today. Neandertal were likely just as smart as we are, were far stronger, could hunt over longer distances, had better tools than the first humans who met them on their way out of Africa. Erectus was better at walking and running than we are and didn't have the back problems people do today. We are each adapted to our niches. It doesn't make one superior to the other, just more suited at some things than others.

originally posted by: peter vlar
a reply to: TinfoilTP

self awareness and knowledge of science doesn't make us the pinnacle of evolution though. It just makes us more knowledgeable than those who came before us. That's you forcing an anthropic principle where it doesn't belong. Physically, Neandertal and in some ways, Homo Erectus were superior to the humans walking the Earth today. Neandertal were likely just as smart as we are, were far stronger, could hunt over longer distances, had better tools than the first humans who met them on their way out of Africa. Erectus was better at walking and running than we are and didn't have the back problems people do today. We are each adapted to our niches. It doesn't make one superior to the other, just more suited at some things than others.

Your whole diatribe describes entropy. Thanks for supporting my view.

This is just stupid in so many ways. Your effort in an attempt to appear intelligent is readily obvious. The question, which you hinted at but didn't even outright say, has been addressed in evolutionary biology, long ago, numerous times.

a reply to: peter vlar

Howdy,

I'm not familiar with European phacopids, but I don't see why they couldn't be similar to American populations, especially if the trilobites are from a period of time before much opening of the Atlantic. Interesting you should mention the Eldgredgeops vs. Phacops naming thing. It hasn't stuck with collectors, although Eldgredge's papers seem to indicate enough morphological distinctions to support the change (which has, in my limited experiences, been accepted). Of course, I was referring to the order Phacopida (which the genus Eldgredgeops is a member of).

And yes, I agree that this example of lessening eye facets is still evolution in response to environmental differences and natural selection. However, I thought this particular case of evolution was one such example that fit the OP's defined "devolution." Perhaps I am not being clear myself... When I write that there is an apparent directive force, I emphasize the "apparent." It appears that way, yes. But as you say, yes, it is natural environmental pressures directing evolution.

Don't get the wrong idea. I'm a proponent of modern evolutionary theories (and I must bring up punctuated equilibria because we are mentioning Eldgredge), but I don't mind allowing others to operationalize their own terms. If I can demonstrate that 'devolution' is still evolution, then what do I care what it is called? Although I do admit it muddies the issue, at least initially.

As for the multicellularity issue, I'm not really sure. You've hit the issue dead on. There is a lot of Earth history that is currently unknowable and may forever be unknowable. Genetic information may be the best available resource. However, I suppose the "consensus" is now at least 46 independent evolutions of multicellularity? Haven't read the cited papers yet though...
en.wikipedia.org...

And on somewhat related note, you seem pretty knowledgeable about trilobite evolution and lifestyles yourself. I'm glad I'm not the only one around who likes the little arthropods. Whatsmore, they are significant to the modern understanding of evolution. As for the diet of Eldredgeops, I do believe the hypostome is suggestive of a predator, too.

scholar.google.com...

Finally, let me thank you for making me clarify myself. I'm not the clearest or most concise of writers. You yourself clarified some of the things I was trying to say in a way that I probably could not.

Sincerest regards,
Hydeman

originally posted by: chr0naut


To me, by observation, it appears that there has been an overall 'direction' of life processes towards biological complexity, functional efficiency and integration with existing lifeforms. Yet in a stochastically neutral environment, it should be expected that there would be equal movement contrary to those concepts. For the purposes of this discussion, I'll call this 'devolution'. Do you know of devolutionary examples and, if there are such devolutions, why are they not as equally apparent as evolutionary ones?

Is this your own wording?

I ask because:

To me, by observation, it appears that there has been an overall ‘direction’ of life processes towards biological complexity, functional efficiency
and integration with existing lifeforms. Yet in a stochastically neutral environment, it should be expected that there would be equal movement
contrary to those concepts. For the purposes of this discussion, I’ll call this ‘devolution’. Do you know of devolutionary examples and, if there
are such devolutions, why are they not as equally apparent as evolutionary ones?

source