Why we don’t want another “Synthesis”
High-level debates in evolutionary biology often treat the Modern Synthesis as a framework of population genetics, or as an intellectual lineage with a changing distribution of beliefs. Unfortunately, these flexible notions, used to negotiate decades of innovations, are now thoroughly detached from their historical roots in the original Modern Synthesis (OMS), a falsifiable scientific theory.
The OMS held that evolution can be adequately understood as a process of smooth adaptive change by shifting the frequencies of small-effect alleles at many loci simultaneously, without the direct involvement of new mutations. This shifting gene frequencies theory was designed to support a Darwinian view in which the course of evolution is governed by selection, and to exclude a mutation-driven view in which the timing and character of evolutionary change may reflect the timing and character of events of mutation. The OMS is not the foundation of current thinking, but a special case of a broader conception that includes (among other things) a mutation-driven view introduced by biochemists in the 1960s, and now widely invoked. This innovation is evident in mathematical models relating the rate of evolution directly to the rate of mutation, which emerged in 1969, and now represent a major branch of theory with many applications. In evo-devo, mutationist thinking is reflected by a concern for the “arrival of the fittest”. Though evolutionary biology is not governed by any master theory, and incorporates views excluded from the OMS, the recognition of these changes has been hindered by woolly conceptions of theories, and by historical accounts, common in the evolutionary literature, that misrepresent the disputes that defined the OMS.
Read. Discuss.
Do you agree that your genetic makeup was determined by the action of two cells, a sperm cell and an egg cell?
Well let’s look at the evolution of birds which, I’m sure you agree, is some distance from the line of human evolution.
If you accept the tree of life they have evolved from beginning as single celled organisms that were at the mercy of their surrounding environment as regards to fluctuations in chemical conditions and temperature. They went through a stage of being multi-cellular fish like organisms which laid their eggs into the environment and then left them in the care of this environment. They moved on to the land and became air breathng which freed them from being confined to an aqueous environment but they were still basically exothermic reliant on the external environment for providing the heat they needed. They then developed endothermy which was a step in the direction of self-control. They began to care for their young, a further step of emancipation from their environment. They took to the air, thus taking a further step in freeing themselves from forces of the earth.
Pick any phyla you wish and we can discuss if they show a similar trend of emancipation.
Or to put it another way, how the cell uses the DNA that is contained within it.
I’d like Proteobacteria, especially Buchnera, please.
No, how the DNA uses the cell that encapsulates it. Don’t you see?
If you are looking for trends you cannot just look at a single example such as the one you linked to. You need to look at proteobacteria in general.
Would you say that motility give greater autonomy than sessility? And would you agree that in the evolutionary history of proteobacteria sessility is believed to have preceded motility?
This is an example of a move towards autonomy.
Within reason can you give us a detailed description of how the DNA does this?
Like keiths trying to use a book. Or computer.
I don’t see. So you think DNA is the master controller using the cell the way a hard drive uses a computer?
I would like to see your source for this so that I can see what was involved in the experiment/s.
If you were to insert the DNA of a frog into the egg cell of a newt would it produce a frog?
Proteobacteria is a tremendously diverse group, so you can find both flagellated and non-motile specimens. The reason I picked it is that it also has a fair share of obligate endosymbionts. Buchnera is a splendid example, which also has one of the smallest known genomes as a result. Needless to say, it cannot survive without its host. I was just wondering how you would rhyme that with an increase towards autonomy.
Do you think that the cell is the master controller using the DNA like a piece of hardware needs some code to run?
I think both perspectives are ridiculous. Mikkel phrased it correctly: there is an interaction between the two. It just happens to be the DNA sequence that gets stably inherited.
See my response to Mung. I was just trying to shake up your perspective a bit.
And soon they had to breathe air. They could not live freely underwater, but at best could stay in the water a few minutes until having to surface to breathe, like penguins and auks.
It’s a bit more self-control, but hardly frees them from the environment that has to provide the chemical energy for endothermy.
Really? Parents having to go to the environment to feed their babies for an extended period is emancipation from their environment?
They became more mobile. They’re not free of gravity, and may use it for speed, as in falcon’s swooping on pheasants.
What about amoebas? Or cyanobacteria?
Glen Davidson
Oh, and somebody is going to mention mitochondria soon.
Just a warning.
Some organisms progress towards autonomy some regress. What I am looking for is general trends. The most successful organisms in a Darwinian sense are generally not the ones that have progressed the most in this regard. Bacteria are a good example in that they are less autonomous than mammals but they produce vastly more offspring than do mammals.
I don’t see how organisms that you think have “progressed the most” are not the most successful organisms. Birds aren’t quite successful? Mammals aren’t? It hardly matters whether bacteria produce far more offspring in terms of fitness.
What we do see are organisms evolving to exploit opportunities. Bacteria continue to exploit the old ones, fewer evolve to exploit newer ones, like parasitic living in birds or mammals. Viruses take parasitism to new efficiencies, mostly reproducing nucleotide strands, and packaging them into new infectious particles.
You just have to see things in terms of progress, when there seems to be no sense to that, while evolution to take advantage of opportunities appears to explain what’s going on quite well.
Glen Davidson
CharlieM,
What’s your point?
Earlier you asked:
I responded:
Do you see why there is no woo there?
In The Evolution of Beauty, by Richard O. Prum, the author briefly discusses whether unification of theories is appropriate:
Maybe it’s more pertinent here if we change “adaptationists” to “Mungists”?
Walter Kloover, quoting Richard Prum:
Definitely not. It’s just an application of Occam’s Razor.
I think one has to take into account the fact that you ARE bacteria. You couldn’t exist without bacteria, that make up a good percent of your body. Bacteria are so successful that the living world couldn’t exist without them.
I don’t think evolution has a good explanation for that.
phoodoo,
How is that a problem for evolution?
I don’t think you have a good explanation for that. What is yours and how do we test it? What experiments have been done? What does it predict?
You do?
Every living thing that existed after bacteria needs bacteria to exist-and evolution predicts that?
If you were still trying to dispell the accusation of anthropocentrism, you did a very bad job by claiming that “bacteria” are less autonomous than mammals. For starters, you are displaying a profound disinterest in anything-unlike-us by sweeping the vast diversity of bacterial species under the rug. Secondly, many bacteria are autotrophs which makes them independent of other organisms for the acquisition of energy and organic compounds. In terms of autonomy, that makes them superior to us.
I strongly doubt that there is a trend towards increased autonomy, and even is there is I doubt that we will come out as the most progressed.
Is it required to do that?
Guess that some body is me. I don’t know whether you accept this, but all mitochondria are believed to descend from free-living alpha-proteobacteria. So every eukaryote is carrying around its own collection of enslaved proteobacteria* around. So much for autonomy.
*or maybe they have enslaved you, take your pick 🙂
You mean is the theory of evolution required to predict anything that actually happened?
Apparently to a lot of people, no.
Anything is OK, but is it required to predict everything that happened?
Isn’ t the main purpose of evolutionary theory to explain patterns of biodiversity? Why many organisms require bacteria to thrive seems like a question for ecology to me.
Corneel,
Are there some animals that don’t require bacteria?
Stretching it a bit to include chloroplasts as endo-symbiotic cyanobacteria, all eukaryotes rely ultimately on autotrophic bacteria for their existence.
I don’t think so. Some associations are even pretty intimate, as in the case of Buchnera and aphids I mentioned above.
Right, that’s why I am wondering why you said this?
You meant “ALL”, right?
Alan Fox,
Right, so we have a theory which says we start with bacteria. Then everything on the planet after that requires bacteria to exist.
So, as far as we know, you can not have evolution without bacteria.
Another lucky accident?
https://www.acsh.org/news/2017/09/29/sonochemical-synthesis-did-life-originate-inside-collapsing-bubbles-11902
Any story is better than no story at all!
alpha-proteobacteria is a made-up name for a made-up organism that may or may not have existed.
Where do you pull these arguments out of?
Alphaproteobacteria is a group of bacteria that exist right now. They include some that can infect you with serious enough diseases that, if you get them, you will be forced to admit that the bacteria really do exist.
Wikipedia page for the group: https://en.wikipedia.org/wiki/Alphaproteobacteria
I don’t need evolutionary theory to see that organisms will use the resources that are available to them.
You know, some of your remarks make me think this also applies to “Mung”.
I should have checked first. 🙂
So there you have it, a rabbit in the Cambrian. Or in this case, a modern organism (alphaproteobacteria) in the pre-Cambrian.
And no more of that “why do we still have monkey’s” crap.
We have eukaryotes, which evolved from alphaproteobacteria, and yet we still have alphaproteobacteria.
Take that creationists!
I am just going along with what I have been told by some believers in blind evolution. Which is that bacteria are much more successful than humans I presume because there are many more of them, they reproduce more and so pass on their genes far more frequently than humans do.
I would hope that when you look at the development of a human from a single cell to a rational thinking adult you see that as a progression. Life is a unity and it has evolved from single celled organisms to produce rational thinking individuals, but you do not see this as a progression?
I’d like to say more but I’m out of time.
But you don’t actually believe that, or what? I certainly don’t. If we don’t know, then that is the correct answer. We don’t just want stories, we want facts that can be observationally or experimentally tested.
There is an evolutionary account for symbiosis (endo and otherwise). And particularly from the standpoint of the origin of the first niches. The first forms of cellular life that evolved would necessarily have to have been primary producers, so either photoautotrophs or chemoautotrophs. Primary produces make a lot of organic waste material, either as a byproduct of their metabolism or simply when they die. This leaves a huge untapped resource of organic material in the emerging ecosystem. So the next niche to evolve would probably have been heterotrophic (detritivore) decomposers (sorry for all the technical terms). This would be immediately beneficial to both parties. The primary producers would go on making a lot of waste, which the decomposers would get rid of, so the primary producers literally don’t drown in their own shit and dead bodies.
Now it’s your turn. How did this relationship come about? When? Can it be tested?
Are you aware of a non-made-up name? For anything? 😛
I guess we owe everything to prokaryotes.
I don’t know. What seems to have happened on Earth is that all the biochemical pathways evolved in prokaryotes. And then there was no need to re-invent the wheel. Why bother with your own biochemical apparatus when you can co-opt a bacterium? Why synthesize your own sugars from water and carbon dioxide when you can get symbiotic cyanobacteria to do it for you? Why generate your own ATP when you can use alphaproteobacteria to do it for you?
How it happened is something scientific enquiry might answer. Why it happened, perhaps not.
Yeah, sure.
Nope.
When materialists talk about biology using these kinds of terms, what the hell do they mean? What do you mean when you say “no need”? When you say “why bother”? When you say, you can “co-opt”?
Because I am pretty sure you don’t mean a need. Or you don’t mean it would have been more troublesome. And you don’t mean the organism is actually co-opting right?
Because it sounds like you are saying, if there was a need they would have done it differently. Or if it was bothersome, they would have used a less bothersome method.
It also sounds like you are saying they could have used their own own biochemical apparatus, or they could have synthesized their own sugars from water and carbon dioxide, or generate their own ATP if it was more convenient at the time. They would have invented a new wheel, if someone else didn’t do it for them first.
But you don’t mean any of that shit do you? Its just a way of replacing words with what you really mean, only we have no idea what you really mean, and I assume you also don’t. Its the biologists excuse that “Well, you know its just easier using teleology words, but of course we don’t mean teleology. Are you kidding, why would we mean that?”
But the easier way-the way of using teleology words when you don’t mean teleology words- is so much less clear. In fact, it is so unclear, that it makes what you write totally meaningless. “Why bother…well, I guess they could have if they wanted to, …it was convenient at the time…”
That is just nonsense words Alan.
He seems to be arguing for some sort of Lamarckism.
Why bother with your own biochemical apparatus when you can co-opt a bacterium and inherit the acquired characteristics?
Why synthesize your own sugars from water and carbon dioxide when you can get symbiotic cyanobacteria to do it for you and inherit the acquired characteristics?
Why generate your own ATP when you can use alphaproteobacteria to do it for you and inherit the acquired characteristics?
Mung,
Yes, and if you don’t exist yet, and the only way you could exist is through bacteria, why refuse to come into existence just because its the only way.
Mung:
Add “acquired characteristics” to the list of things Mung doesn’t understand.