Short answer: yes.

Slightly less short: If it wasn't (but see above, it is), a more parsimonious answer than all others would be that the maths was wrong (but it's not).

Richard Lenski's work is definitely well worth reading. He and his group have shown lots of evolution within the timescale of a PhD project. Repeatedly.

Well, I believe there is no mutation per se in either amino-acids or the protein polypeptide chain, but in the codons (and probably duons) that carry the code for creating them (mRNA).

I would however point out to this paper where they provide a very good argument for the question you are posing. Albeit not being an expert in the matter, I do agree with their conclusions. http://www.pnas.org/content/107/52/22454.short

Alternatively, you can look at papers on mathematical models for complex systems and self-organization. Have a look here for an introduction:

http://pespmc1.vub.ac.be/SELFORG.html

Remember that evolutionary change is not limited to mutations, but also is influenced by selection and genetic drift. Selective agents (e.g. predation, climate, etc.) can lead to rapid evolution. I know everyone here knows this, but it seems to have been omitted from the question and the answers. Perhaps the original question was meant to ask if modern diversity could have arisen by mutation alone in 4.3-4.4 billion years (based on the recent evidence in Nature Geoscience showing that life could have existed 4.3-4.4 billion years ago).

Since mutation is the only primary source of diversity - which then is influenced by selection, migration, drift, mating - you probably ask if 5.54 billion years are enough for mutations to produce all the existing alleles of all genes plus the ones that are lost on the way. With a roughly estimated mutation rate of 1/10^-4 to 1/10^-6 per gene per generation and the fact that each individual of each species has thousands of genes, then I suppose that time was more than enough to produce the basis of allelic richness that exists today in nature. Also think that life on earth is much younger than the geological life of our planet, probably the half.

I wish to ignore all creationist crap here. Mathematical probability is completely irrelevant, as the outcome is what it is, what we are. We know a lot about molecules but we cannot know the exact circumstances in which the first chemical and then biological evolution took place. I think in lottery (here in Finland) the probability that the "right" combination of seven numbers comes out is about one in 15 million, and yet every week some combination does come out, although it had exactly the same probability as any other combination of seven numbers. It is absurd to ask "how probable is it that we are here?"

I do think it is an important and relevant question, even if the answer can only be philosphical until we discover life somewhere else.

Until then, it is a "sample size of one" problem with all statistical implications.

Nobody knows if the chance of life getting started on a favorable planet is tiny or high. That is one of the main reasons why people want to build very large telescopes to view extra-solar planets (it would be interesting to know if one can find extra-solar planets with oxygen, because O2 is an indicator of life).

As for what happened after life got started, there is lots of data about that here on Earth, so detailed answers are possible. The probabilities, expected amount of time for changes to occur, etc, these are known, tested, compared in multiple ways (e.g. fossils vs DNA), etc.

I attended a creationist talk, and the most convincing argument he made was that favorable mutations are unlikely to accumulate "quickly" (even on geologic time scales). After analyzing the argument, I realized that it only applies to asexual reproduction. Sexual reproduction is a method in which favorable mutations can accumulate fairly quickly (on geologic time scales). The end result of the argument is that we should expect evolution to be slow in asexual reproduction, but much faster in sexual reproduction (note: you might think that bacteria should then evolve very slowly because they reproduce asexually, but this is not quite the case because bacteria do in fact exchange genetic information, and at the end of the day, all that the creationist argument really proved is that evolution will be slow if there is really no exchange of genetic information taking place, but that's not how biology operates in the real world).

Species are not cleanly separated. A big chunk of your DNA comes from virusses having inserted their genetic information into one of your ancestors. Comparing your DNA with other species, particularly the parts of your DNA with clear viral origin, gives extremely strong evidence of common origins.

If you want to calculate probabilities, consider this: If chimpanzees and humans do not share common ancestors, then what is the probability that these two species have hundreds of positions in their DNA where viral DNA was inserted at exactly the same position? (the type of virus matches each time as well)

I think it is a relevant question that might be answered to some debree by biophisicists who have determined mean mutation rates in DNA, be it out of theoretical considerations or experimental (i.e. archaeological) statistics. The assumptions that the process be linear, punctuated or episodic are of course relevant. Good topic for a PhD thesis.

The religious viewpoint is beside the point.

You know, scientists actually do work on this problem. It is not a philosophical question, since life obviously has originated at least once, and the best of our evidence suggests that life did indeed originate here on Earth. The question of whether there is work toward the questions of probability and elapsed time can be answered as "Yes". Some accessible work on this topic, though not the most current, would be Eigen and Schuster's "Hypercycle" and Stuart Kauffman's "Investigations". No comment on the creationist nonsense. Oh, and someone above mentioned Maynard Smith: Maynard Smith and Szathmary's "Major Transitions in Evolution" is also very accessible.

Short answer: yes.

Slightly less short: If it wasn't (but see above, it is), a more parsimonious answer than all others would be that the maths was wrong (but it's not).

Richard Lenski's work is definitely well worth reading. He and his group have shown lots of evolution within the timescale of a PhD project. Repeatedly.

Yes - Estimates of evolutionary change are based on a conservative rate of mutational occurrence. It is not therefore out of reasonable speculation to have achieved this within 4.54 billion years. It is however impossible to have achieved this within 6000 years. So for those trying to use this to put creationism into science just remember that Charles Darwin, the devout Christian that he was, himself tried, failed and concluded that evolution was the only way for this level of diversity to have arisen.

As #Peter Keller said, we have a sample size of 1. But we also have a probability of 1. I think, therefore I am. And if we are, then it did happen. Apologies for the obvious circular reasoning, but it is kind of inescapable, as we are here and we did evolve within that time scale. Or is anyone seriously considering the idea that we were seeded by astronauts?

The problem is, we are part of the sample size of one. That life came into existence on earth is clear and has probability one (because we are living proof that it happened), indeed. But it is a conditional probability.

There is no hope to calculate the probability of life in general, as long as we don't find other "samples", as we, in some sense, don't have access to the whole sample space. We can only speculate how it happened and there are good people out there who try exactly that.

Luckily however, there is not the slightest indication that we were created by a divinity or star travelling species, neither is there any necessity for it.

It would be useful if the authors or citators of articles on evolution rate would give the exact bibliographical reference, so we can decide on the question on the basis of their analyses. Philosophy doesn't help to resolve the question: can the diversity of life at present be explained by random mutations + survival rate + global extinction events + everything else? Is it the invisible hand of God or is it that of the free market?

The only true answer is: 'Yes, it is. On this planet, under the conditons that ruled on this planet since its formation, 4.54 billion years are mathematically sufficient'.

If then you ask why, well... there is no other answer than life on this planet is the only evidence of that time gap to be enough.

Actual science proves it did. As soon as you have true cells, even procaryotic, with nucleic acid and protein synthesis machinery, the time elapsed is fully compatible with complex evolution. The question of prebiotic evolution is much more tricky as we know very few about it. Even LUCA can only be reconstructed under the hypothesis that it is an organism based on a nucleic acid, likely a RNA but what about before ?

Your question seems to assume steady, gradual microevolutionary change over billions of years. The paleontological evidence indicates that the evolutionary process is episodic in the extreme. We do not yet have a reasonable explanation of the mechanisms that drive macroevolutionary change, most of which seems to have been very rapid (see my review "Breakthrough on the Cambrian Explosion"). So, the question of whether 4.5 billion years is enough time to account for observed evolutionary divergence is beside the point, because evolution does not seem to have occurred in a gradual-Neodarwinian fashion. Poorly understood and apparently fast evolutionary transitions have occurred between the major groups.

In attempting to answer a question like this, one should consider their assumptions. For a die hard new earth creationist there is clearly not enough time. For someone committed to only evolution being the factor, there clearly had to be enough time. If one falls somewhere in between these positions, possibly some variation of directed evolution, the question might be answered either way. I will stand with there being enough time though, thus ruling myself as not being a die hard young earth creationist, but not revealing much beyond that.

Adding to Mark Mcmenamin's answer, there is much beyond macroevolution and we are still figuring that out as he stated. I would add that apart from outside selective pressures due to negative interactions (predation, parasitism), positive interactions have been paramount to evolutionary changes. All the major transitions in evolution (as per Maynard-Smith) involve organisms "learning" to collaborate to become more efficient - eucaryotic organisms, multicellular organisms, social organisms. This leads to highly non-linear paths for evolution to follow, and steps appear where before the road appeared to be even. Another important phenomenon is niche construction, in which the change exerted by some organisms on the outside environment becomes an extended phenotype. The effects of this extension are not only crucial for the present generation but can be inherited by the following ones, leading again to non-linear interactions between environmental selective pressures and evolutionary responses of the organisms in question. As suggested above by other contributors, the mathematics is much more complicated than simply adding adaptive mutations and subtracting the bad ones... in soma, it could have taken less than 4 billion years for evolution to come to where it is, it could have taken more - it's not simple ballistics.

I think the single most convincing bit of data comes from Philip Gingerich's 1983 classic on rates of evolution, published in Science. Gingerich plotted rates of evolution as estimated from data collected over different time intervals. He plotted lab data using microbial populations, field studies of usually one to a few years, and on out to paleontological time scales. Rates collected at short time scales are ever so much faster than those estimated from the fossil record. The simplest interpretation of this pattern is that selection in the short run is responding to all sorts of noisy environmental variation. The long term net changes in the environment are generally slower, so long term evolution averages out a lot of short term variation. Thus, evolution seems to have ample "reserve capacity." If there had been sustained rapid, directional environmental change, evolution would probably have kept up.

Of course in the rare major extinction events, most lineages do fail to keep up with very rapid or very extreme environmental change. But it seems to take only a few million years for diversity to recover after mass extinctions, also suggesting that evolution is a pretty rapid process.

The Cambrian explosion that gave us the first diverse fauna of large animals with skeletons was pretty rapid too. It probably represents the first time large volumes of seawater carried enough oxygen to support the high energy physiology necessary for large animals.

John Thompson had a book out last year with Chicago entitled Relentless Evolution. He reviews a large number of field and lab studies illustrating the rapidity of everyday evolution in response to selection pressures varying in time and space.

The question is wrongly formulated, as evolution is certainly not driven only by mutations, but also and largely be selection and to a minor extent by genetic drift. The rate of evolution is, in the univariate case and for a single continuous trait:

R = h2*S

Where R = is per-generation phenotypic response, h2 is narrow-sense heritability and S is the selection differential. This is the so-called "Breeders equation of quantitative genetics".

Most morphological traits have heritabilities well above zero, usually around 0.4 on average. It does not require much selection with this high level of heritability and not many generations to turn a mouse in to an elephant, provided that selection is chronic and persistent.

Thus, your question should be reformulated: "GIVEN high amount of genetic variation and high heritabilties and strong selection, why has not more evolutionary change happened during 4.5 billion years, and why is stasis more common than change?". The main problem for evolutionary theory is therefore to explain why organisms do not change more often and so slowly, rather than to ask if time is sufficient. It is clearly sufficient, it is MORE than sufficient.

Yes, definitely yes. The proof is the fact that we are here.

If it were not possible, no one will be here to ask the question, and , of course, to answer the question

Arieh

Asa #Arieh Ben-Naim well said. The proof is that we are here. If we came to the conclusion that the answer is 'no', then we all will cease to exist. :-)

@Erik, the mouse and the elephant have essentially the same basic body plan with some allometric adjustments. This is ordinary microevolution. The real challenge, quite unexplained at this point, is how you go from the mouse to, say, a sea urchin with its fundamentally different body plan. @Fernando and Arieh: What you are saying would seem to be consistent with the Strong Anthropic Principle (SAP).

Dear @Mark Mcmenamin

I prefer to think that I agree with the Weak Anthropic Principle, if you state it as such: If the universe was not able to produce us, we wouldn't be here and we wouldn't know it existed.

Bacterial genome contain only 200- 1000 genes , while human contain 30,000. How come a higher number of genes evolve from a lower number ? Mutation explains alteration in an existing gene to make better or make it a non-functional gene. How random mutation explain emergence of completely new genes which have a survival benefit. Kindly also calculate the number of lethal mutation that may occur to accumulate one gene which is beneficial or have significant survival advantage! Is it that many bacterial genome fused together and mutated to give the yeast genome? Or we accept the dynamic intron exon concept . This means what we accept as intron in one organism may be exon in the other or vice-versa. It may be so that even within body of the same organism, intron and exon lengths vary mutually . What is exon in kidney may be intron in the heart . This may explain that how we have more proteins than predicted by the absolute gene-numbers predicted by sequencing.

S. S. Maitra

One important source of new genes seems to be gene duplication. Errors in genetic transmission sometimes result in extra copies of a gene being produced. Duplicated genes are candidates to be co-opted for new functions.(http://en.wikipedia.org/wiki/Gene_duplication)

Yes!

Ernst Mary probably had one of the best definitions of "evolution"--as the change in gene frequencies in populations of organisms. So, the annual change in flu strains demonstrates evolution as antibody-driven selection on the viruses leads to a change in virus genome, while heavy commercial fishing quickly drives fish to reproduce earlier in life and at smaller growth stages. There likely is no simple mathematical answer to your question as factors well above the level of mutations (of genes, not their product amino acids), such as community evolution are likely the strong selective agents that "drive" episodes of evolutionary radiation. Just as the concepts of a very old Earth and Darwinian evolution accorded with the successive appearances and extinctions of magor groups of organisms by the mid-1800s, modern, precise dating techniques (as U-Pb of zircons) help determine rates of major evolutionary replacements. So, I think it can be said that the fossil record and precise age dates show the unlikelihood of useful molecular clocks, but rather great changes in rates of evolution followed by lengthy relative stasis--a really difficult history to model mathematically.

The problem is, how exactly to compute the probability for evolution to take place again?

Using models, #Hemanta Baruah, using models.

It depends on what you mean by "take place again". If you mean here on Earth, evolution never stopped, and never will stop as long as life persists. If you mean elsewhere in the universe, there are, I'm afraid, insufficient data for a meaningful answer. At least right now -- this is one reason why scientists continue to look within and without. Within, they try to learn how life originated here, and the conditions under which it happened. As reasonable ideas for this develop, it may become possible use new observations of distant stars and planets to estimate how often, among Carl Sagan's "billions and billions of stars in billions and billions of galaxies", these conditions may have arisen.

Dear Fernando,

Is there any way to know whether such a model is acceptable?

Dear #Hemanta Baruah

The model is useful / acceptable while experimental data (observations) fit it. The moment they don't agree it is time to ditch the model and propose a new one that does agree with the observations. This is the way Science works.

Horizontal gene transfer between bacteria and viruses, along with symbiosis, contributed enormously to the development of genetic processes and to the evolution of more complex organisms such as ourselves. When you consider the exponential nature of evolution across lineages and their interactions, then evolution as we understand it is plausible. However, the evolution of modern cells (modern as in ~2 bya) is wide open. Consider further that the traces of life are present in rocks ~4 bya. We have not got to the bottom of the matter yet, leaving open the possibility of panspermia. That of course opens another can of worms... Given we know exceedingly little about the conditions under which "life" initiated, it is going to take a lot of work to unravel the mystery of mysteries.

I will begin by stating that I have not looked into this for several years, so things might have changed, but when I last looked into the question of the "Last Universal Common Ancestor" (LUCA) the consensus was that it never existed. Does anyone know if the consensus on this point has changed? If it has not changed, then the question of genetic diversity shifts because we have a much larger pool to start with then if we have a single set of genes.

Dear Fernando Schlindwein,

Data are collected, and a model is hypothesized. If the model fits the data well, we declare that the model defines the underlying natural law.

But in this case, which kind of data are you going to use? Natural laws have always been there; from collected observations, we try to uncover the law concerned. That is how science has proceeded. In the current case, is there an underlying law?

Its a long time to wait for a bus!

But seriously, my own work suggests that life may represent the evolution of a single type of process - catalysis. The work is cited in a paper that addresses this very

question.

Mitra-Delmotte, G., and Mitra, A. N. (2012). Softening the “crystal scaffold” for life’s emergence. Phys. Res. Int. 2012, 13.

I had always a question related to evolution theory: Why current monkeys, chimpanzee and other hominids have stopped evolving and have been very fixed species? Did evolution come only for a small time interval and then ... the door simply closed?

Wait, what? What do you mean, "stopped evolving"? All of us ["current primates"] continue to experience selective forces and produce offspring with variable hereditary characters resulting in relatively different reproductive success. Evolution is a continuous process. There are probably a number of "incipient" species developing as we speak - but because we are in the middle of the process, it is difficult to see where it will wind up.

Examples of potential allopatric speciation:

1.) How many generations before macaques or chimps imported to the United States as research primates and left to retire on open farms in Texas or Florida become zygotically isolated without regular drift from other populations?

2.) What about habitat fragmentation in Africa, Asia, and South America, as development pushes or eliminates bridges between populations?

Potential sympatric speciation:

1.) Perhaps human-mediated extinction has eliminated a major competitor or predator from a particular environment; surviving primates now compete to fill that particular niche, or continue to diversify and exploit specialized niches within their own environments.

Ongoing major selective forces:

1.) Human development changes habitat drastically, and survivors must adapt or go extinct.

2.) Global warming expands old ranges and changes ecosystems drastically; survivors must adapt or go extinct.

I see ... probably it is not possible to do a plain conversation without being stoned (two downvotes for a simple question...?) I remember the advice of an elder man about passion and its strong correlation with specific scientific fields ... he was so right! OK fellas ...

Hi Demetris, I do not know where did you pick up the mis-information that some or any organisms could have "stopped evolving"! Your assertion is absolutely false. All the species that exist (or have existed) on this planet continue to evolve ALL THE TIME! Like Andrew said above, it is a continuous process. Hence present day humans are evolving, just like the present day chimps are.

I think your question got down-voted because it is based on a false assertion which betrays a total ignorance about the meaning and mechanisms of evolution!

I will try to to compile specific examples of recent human evolution if you are truly interested.

Best,

~a.

Dear Amit, I meant the evolution of monkeys to human beings, that's all. Have you any evidence about such a process?

Dear Demetris Christopoulos

Monkeys did not evolve into human beings. Monkeys and humans had a common ancestor.

Mr. Christopoulos, I see from your profile that you are an economist, and perhaps this explains your lack of awareness of certain defining elements of biology.

Evolution is a blind and directionless process whose "victories" are only described in terms of a lineage's ability to keep its descendents playing in the game. It is not a "ladder", with one form of life gradually developing into another in a procedural fashion, and any one being more "advanced" than another. There never was a rank following from bacterium --> protozoan --> sponge --> fish --> reptile --> mammal --> primate --> humanity. All of those organisms are different attempts by competing but distantly related strains of DNA to continue reproducing themselves in the environment. They are all the sophisticated end-products of billions of years of evolutionary history. All of them continue to evolve as populations!

To draw an analogy from a human family tree: you are the most recent end-product of your family's evolutionary history, but this does not deny the possibility that you might also have cousins. Humanity shares a common ancestor with monkeys - just as you and your hypothetical cousin share a common ancestor in your grandparents.

Evolution is a process by which one species or another gradually adapts to better survive in a given ecological niche. There is some evidence of possible human evolution going on in the gradual increase in the number of people who have the super good form of cholesterol. All people who have this specific form are descendants of one specific couple, and the normal arterial plaque simply does not develop in their arteries no matter what high cholesterol foods they eat. These people have a definite survival advantage over the rest of us, and I imagine that eventually this gene will be present in most if not all humans. However, it will also take a long time to reach that point.

Hi Demetris,

No I do not have any evidence of any process in which monkeys evolved into humans, because this actually never happened, that is not how evolution works! What I do have evidence for and what actually did happen was this : There was a common ancestor to both humans and monkeys but which itself was neither a monkey nor a human, whose offsprings gave rise to independent lineages / populations, which continued to evolve over many subsequent generations to give rise to the present day monkeys and humans etc. (This is again what Fernando and Andrew have already explained above).

Your statement about "evolution of monkeys to human beings" again stems from you having a very wrong concept of evolution! The whole idea of there being a straight line of descent from monkeys to humans is wrong, but unfortunately this is a very common mis-conception that many people continue to have. I think one of the reasons for this is widespread use of cartoons or caricatures in which one starts with a monkey on the left and ends up with a human on the right, but that is just a cartoon and very wrong!

So I will just leave you with two images which explain the errors in your understanding of evolution (and perhaps the source of these errors). The key concepts that you need to distinguish between are "linear descent" versus a "tree of life":

Image 1 source : https://matthewbonnan.wordpress.com/2013/09/14/apparently-ive-gone-viral-or-stick-figures-and-evolution/

and Image 2 source: http://alwaysquestionauthority.com/2013/06/10/evolution-this-is-not-evolution-this-is-evolution-richard-dawkins/

Demetris,

There is lots of neat work on human genetic responses to selection in the present and recent past. My somewhat out-of-date 2010 paper, which you can find on my web site, summarizes some of the evidence. Studies of microevolution--evolution over one to a few generations--is one of the staples of evolutionary biology. A good up-to-date summary is John Thompson's recent book Relentless Evolution. As far as we know there are no fixed species.

Richerson, P. J., & Boyd, R. (2010). Gene-culture coevolution in the age of genomics. Proceedings National Academy of Science USA, 107(Supplement 2), 8985-8992.

Best, Pete

http://www.des.ucdavis.edu/faculty/richerson/richerson.htm

There is a certain resemblance between the evolution of species and the evolution of languages. Glosochronometric research [excuse my scientiese -estimating the lenght of time since two languajes diverged, i.e. French and Spanish from Latin since the low middle ages]. This cannot be measured in DNA differences, but with computers that understand words and grammar, our philologist colleagues have done a good job.

It strikes me that punctuated events also exist with languages, in the form of lost/gained battles between peoples, the dominance of one and the extinction of the other carries over to their languages. Defeat of the other side in Roncesvalles would made Spanish and French dialects of Arabic.

The vagaries of history and the branching/mixing of our ~6000 tongues has been stopped recently, with the imposition of a central dialect for families such as Spanish (Mexican accent), French (Parisian), Italian (Tuscan), English (-a problem here), etc., due to the ubiquity of radio and tv programs in those central dialects. Perhaps species and linguistic evolution depart into two dynamics, with the latter becoming frozen in time, with only a couple of hundred being used as "national" languages,

Further differences to ponder: What is the meaning of a lingua franca, such as Swahili or Bahasa Indonesia, or the various pidgins and creolles? (interspecies breeding?) What about Hebrew, or classical Greek vs. Demoticos? (resurrection of one, cheap magic of the other?). It is probably true that the rules of linguistic change have changed from species evolution to a new set of rules due to government, massive comunication and globalization. (Are we not depleting the natural biodiversity to just a few useful species?)

Actually, surprisingly perhaps, languages continue to evolve. Many small languages are going extinct while dialects of big languages continue to change. A rough generalization is that wherever social fault lines arise, language differences tend to emerge. William Labov, the pioneer student of the microevolution of dialect, produced two big treatises. I don't know of any good reasonably accessible intros to his sociolinguistics work.

The most interesting part of the story is that language evolution is led by pre-pubescent girls. Women are more verbal than men and tend to speak more "advanced" versions of local dialects. The ability to master a new dialect shuts down in most people in adolescence. The top-down attempts to control language evolution via official dialects, school instruction, standard broadcast dialects and the like seem to have little effect.

Labov, W. (1994). Principles of Linguistic Change: Internal Factors. Oxford, UK ; Cambridge Mass.: Blackwell.

Labov, W. (2001). Principles of Linguistic Change: Social Factors (Vol. 29). Malden, MA: Blackwell.

We say the same thing, although you are more specialist in terminology: If you see my first post you will realize that every evolutionary route is locked: It started from the same ancestor, but after then every specie has its own evolution and nothing is happened now for examples to monkeys in order to give them the ability to evolve in a higher intelligence level, ie to become something like a human being. Anyway, I thought that here in RG we can discuss in a different way than like being in a church of a dominant dogma (where if you say something outside the mainstream you will be punished), but I realized that the mentality of the specialists is very similar to those priests that sometimes scientists take as an example to be avoided: "we are scientists, not priests". Sorry, guys but this is similar to a religion, at least for me. As for the main core: I suggest you to do 3 things: 1)relax, it is just a forum 2)read Hesiodos with open mind, without taking every word as exactly its meaning, in order to realize that there have been other 4 evolutionary eras in humanity and we are the fifth attempt 3)after all you read in Hesiodos, think that 200 years of theories is a very small time for such a so strong selfish behaviour. Bye to everybody, I am sorry to realize that modern science and old style religion have so many, so many similar characteristics...

"Every evolutionary route is locked".

I suspect that you are not adequately expressing your hypothesis.

You're not looking at dogma or ideology, you're starting to ask some of the interesting questions that first year students of biology often ask. You're late to the party. Fortunately, there have been a number of theorists and philosophers who have attempted to address or resolve your questions over the decades. As an example, one of the central themes to Steven Jay Gould's "Wonderful Life" (1990) is to ask the question: if we started the game of life all over again, would it play out in identical fashion? Would we end up with the same phylogenetic diversity we currently have, or might meter-long Anomalocaridids still hunt somewhere along coastal reefs, and mammals never arrived?

Alas, this is mostly a rhetorical question. Paleontology is inevitably a historic science; the experiment has already been run and you try and extract what you can from the data. It is very difficult to set up an experiment testing the likelihood of any particular taxon to develop a particular adaptation in response to a particular selective challenge or within a set of unique environmental conditions. There have been some interesting studies with clonal organisms like fungi and bacteria that suggest that minor variations leading to mutation (even among clones!) can be stochastic and therefore similar ancestors can produce very divergent results when you repeat the experiment. These are tough experiments to run, and one needs a large number of test subjects and a long time to run them.

On the other end of the spectrum, one of the major "trends" in evolution has been "convergence", in that similar environmental conditions tend to channel organisms into similar bauplan with similar adaptations. The classic example of evolutionary convergence is to compare sharks to the extinct icthyosaurs (aquatic reptiles) and dolphins (aquatic mammals). They share similar body shapes in response to the constraints of their aquatic environment: the laws of physics suggest that this form is a very efficient body shape for a predator to push through water towards prey. Separate lineages, but they all acheived very similar solutions to the problem of moving through water.

Why then, as you suggest, have more species not evolved into apparently sentient social organisms? Probably for the same reason that not every lineage has evolved a large-bodied aquatic predator. This ties into a concept related to convergence: competitive inhibition. Not ever major lineage of animals can have a representative fast-moving predator plying the ocean simultaneously. The mammals do not arrive as major aquatic predators until after the reptiles go extinct in the late Cretaceous. Your an economist, so I will draw an analogy: the prominence and sheer success of reptiles as predators prevented a new competitor from entering the market - the entrance costs were too high, and the available competitive niches had already been filled by sharks (who persist undefeated) and reptiles.

The human brand of intelligence may be a rare response for a lineage to develop to solve the problem of being alive. Now that it has arrived, it may be difficult for other organisms to develop that same kind of social intelligence and problem-solving capacity that we utilize because we outcompete them in that market. That said, I'd take a good long look at crows, parrots, raccoons, coatis, octopi, and most of the other primates. They are all adept tool-users with some form of social structure - what separates them from us is mostly a matter of degree, and not one of kind. They are all on the list of potential candidates to replace humanity as the primary technology-using species should we drive ourselves (or be helped) into extinction.

If you have a couple dozen spare planets or alternate universes to borrow as replicates, and at least a quarter million years to run the experiment, I'd love to see the results.

"Your an economist..." -> You are an economist..." :-)

It would be great, if at least some of the contemporary researchers would read the old literature again. They would realize that saltatory evolution of nonadaptive characters is superior to survival of the fittest mutant. It can easily explain why, according to the fossil record, species remain stable for 100 000s of years and suddenly a new species with a complete new bodyplan shows up...

Article The telomeric sync model of speciation: Species-wide telomer...

Dear Aria, I don't understand your posting. Nobody says that there was a recent creation.

The problem is that the modern synthesis (neo-Darwinism) predicts a gradualistic phenotypic change of species and very long time spans, but the fossil record shows a saltatory pattern.

I give you an example from the paper mentioned above:

"In his book The New Evolutionary Timetable, the American paleontologist Steven M. Stanley convincingly describes what the major problems of Darwinism and the modern evolutionary synthesis are. He states that the Pleistocene sediments at thousands of collecting sites have uncovered at least 85 % of the mammalian species living today, and therefore the fossil record can no longer be regarded as providing an incomplete picture of evolution (Stanley 1984, p. 97). Most importantly, Stanley mentions the puzzling paleontological fact that within less than 12 million years, most of the living orders of mammals developed, including such diverse animals as lions, wolves, bears, horses, rhinos, deer, pigs, antelopes, sheep, bats and whales, all having descended from a tiny animal resembling a small rodent (Stanley 1984, p. 93). He further concluded: “We can now show that fossil mammal populations assigned to a particular Cenozoic lineage typically span the better part of a million years without displaying sufficient net change to be recognized as a new species. (...) If an average chronospecies lasts nearly a million years, or even longer, and we have at our disposal only ten million years, then we have only ten or 15 chronospecies to align, end-to-end, to form a continuous lineage connecting our primitive little mammal with a bat or a whale” (Stanley 1984, p. 93). “Our only reasonable recourse is to abandon gradualism in favor of punctuated evolution, which can account for the rapid changes for which we see evidence. These changes must have been brought about by strongly divergent steps that came in rapid succession” (Stanley 1984, p. 90)."

I was intrigued by Peter Richerson's response,easpcially the sentence: "· The most interesting part of the story is that language evolution is led by pre-pubescent girls. Women are more verbal than men and tend to speak more "advanced" versions of local dialects"

I have had a long interest in the diversity and evolution of languages, especially as its greatest diversity. With an added fascination with history I have long pondered the impact that women who were unfortunate to be caputred or enslaved might have had on the development and spread of bilingualism, dialects, religion, myths, and languages generally. We forget that slavery is very old and something which has happened for most of human history. I think the role of women in language development has been significant but I have not read any real analysis of it. Perhaps others might enlighten me.

Another puzzle for me is the Cheetah and the Lion which are genetically very close yet so fundamentally different in habit, physiognomy, and ethology. Doe snayone know when they diverged?

In the organisms that I study (Fabaceae) there are some genera with over 70 species yet which have a crown clade age of less than 2 million years. I know of other examples in other genera (eg. Andean Lupinus). That is rapid evolution indeed.

Finally, Economists differentiate between arithmetic growth and geometric growth. Perhaps these are at play in the evolutionary lottery and it is molecualr pathway complexity that is evolving differentailly?

I apologise for my lateness in joining this post (in some ways 23 years). But what delicious answers and examples. And so refreshing to see linguistics and economics in the fray.

So, please forgive my possibly outdated and rusty triple of "what if's" around the philosophy of William of Ockham's famous razor but I am somewhat saddened that Neo-Darwinism is still appearing to force awkward timescales into the paradigm of random mutation separate from environmental drivers as the "blind clock maker" of life's staggering complexity.

To whit:

1. What if saltatory and explosive speciation along with evolutionary conservatism actually are exactly what they appear to be and rates of evolution are largely independent of the inefficiency of expressions of chance mutation at given loci?

2. What if "natural selection" exists as only a (small) part of the majority of evolution processes?

And really, the crux of the argument (as such as it is):

3. Wouldn't pure natural selection in the first instance select those individuals and populations that were able to evolve, or not evolve, efficiently and in concert with the environment in which they live?

I posit that as an argument in logic unfettered by perceived wisdom and current paradigms these are three points worthy of proper consideration (the last particularly).

The simplest explanations for the phenomena of the diversity of life that we observe around us and in the the fossil record (for example the explosive post Cretaceous Pleistocene mammal divergence mentioned above) are probably correct.

What the mechanisms might be is surely where it becomes fun again.

@Demitris,

I think that the answer to your question is that we are here. Monkeys will only evolve into a new niche if it is free. Also, your perspective assumes some sort of innate driving force to evolve. My own view is that it is the environment that drives evolution.

There is a lot of merit to saltational evolution; in particular to chromosomal re-arrangement, duplication. Novel body plans and adaptation arise from replicate DNA that then drifts. Gould's ideas were good, but needed molecular verification. The jury is still out, but the evidence is piling up.

There were many others before Gould, who insisted in saltatory evolution. Theodor Eimer, Otto H. Schindwolf and Richard Goldschmidt. Unfortunately, the gradualistic model prevailed. Please read Otto H. Schindewolf's most famous book.

http://books.google.at/books/about/Basic_Questions_in_Paleontology.html?id=WzDfOuHgBzMC&redir_esc=y

Thank you, you are right. I had forgotten the paleontological literature.

Yes, if you take Scott Aaronson's ideologies ( a professor at MIT) he mathematically shows that genetic mutations are not commpletly random, but rather randomly guided. This meaning evolution does not have to back peddle, but rather when a mutation happens (and doesn't help) the species dies off, but if it does favor the species it stays around. By this method there would need far less time for a certain species to evolve. Thus, proving Darwin's theory of natural selection.

And it's not beyond reason to expect Natural Selection per se to have long ago (the Pre-Cambrian phylogenetic explosion is a tempting conjecture on this point) to favour those species that develop a range of abilities to evolve efficiently in concert with environmental conditions and therefore bring evolution out of the cold and more in line with the negative homeostatic physiological feedback loops that define the natural world yet are not permitted in the world of the Neo-Darwinist.

If the visible evidence is accepted at face value through the simple application of Occam’s Razor the paradox of saltatory (e.g. explosive speciation in new habitat e.g. Lake Malawi cichlids and after major extinction events) and conservative evolution seen in both the fossil record and in species extant today will be seen for what it is instead of the increasingly fraught epicycles of explanation of an increasingly marginalised Neo-Darwinism paradigm of random mutations at a specific loci as the main driver of evolution.

With a little more open-minded approach to research in this field it might be discovered that life long ago learnt the ability to shape its own future by reducing the vast and unpredictable waste of random expressed mutation through various strategies to diversify or to retain stasis as the situation requires. What those mechanisms might be, and following the logic of from observations there may be at least two (to conserve or to evolve) then evolutionary biology may finally escape the strictures of a well over past sell date theory.

When this long overdue paradigm shift does occur (I certainly expected it to have happened by now and it’s a sad testament to the conservativeness of our times that it hasn’t despite the masses of evidence to the contrary) then, and only then, would evolutionists have a coherent argument against intelligent design and creationists per se.

Reading this back I see I have clearly crossed into the realms of fancy where the integrity of rigorous and imaginative scientific enquiry has trumped self-perpetuating conservatism. The reality appears instead that the ideals of the scientific method have been subsumed by ever tighter involuted circles of the scientific establishment no doubt reinforced by ever safer funding requests in the face of ever tighter funding availability maintained by the self-congratulatory clique of the current paradigm’s fundamentalists. In such way does science discredit itself and in such ways does it show that, as in religion, it too can fall to the ego and the unimaginative human slaves of doctrine.

My answer would be no. For a recent argument see the reference to Rosenberg (2013 ) below. Note that I refer to the quote below as an improbable statement that has a physicalist content, not yet complete.

Alexander Rosenberg, well-known philosopher of physics says by referring to adaptation as an asymmetric process (i) driven by the second law, and (ii) requiring it to be wasteful processes, using up more order in producing adaptations than the order that the adaptations constitute and maintain, writing:

It’s clear that the only way to build adaptations consistent with these two requirements is to start by processes that randomly build large numbers of alternative molecular structures just through the operation of thermodynamic noise and then wait. Wait for what? For one or more molecules to turn up randomly that combines thermodynamic stability with replicability. Eventually out of shear thermodynamic noise there may come to be a molecular structure sufficient to withstand the local environment and that also encourages the emergence of copies of itself out of the atoms floating around in the thermodynamic noise. This can happen by templating, catalysing or otherwise producing copies of itself. You probably don’t have to wait more than 500 million years, once the chemical constituents of the early earth were around for this to start to happen. Once it does happen, iteration of the same process will produce more and more adaptation, at greater and greater expense, just as the 2d law requires.

The crucial question is whether we have “at home” all the laws of nature needed to understand how evolution do indeed “produce us”.

In reply to Erkki Brändas, I would say that the most difficult (and fastest?) major leap in evolution was the first one, the biopoesis transition from non-life to life. If you add an additional factor, namely, the fact that the primordial or Haldane Soup is loaded with toxic compounds able to poison any synthetic pathway you can imagine, then not only is there insufficient time, it may be mathematically impossible. Vladimir Vernadsky made Oparin furious with his talk of bio-inert matter, inert matter, etc. to illustrate his view that life was as old as matter and energy. Vernadsky thus became the first to stare deeply into this greatest and most gaping chasm in our scientific landscape.

Yes. The time constants we know have been obtained by observation of what is happening now. Time constants could have been different in the past. Also, this is not a simple linear problem and, as chaos theory tells us, if there was a lucky break early on, then the whole thing would be much quicker. Finally, the good old argument: We are here. Or you guys believe that the gods were astronauts?

Dear Mark,

Thanks for your comments. In a sense I agree that there is a gap in "our scientific landscape". Note for instance the critical statements made by Thomas Nagel in "MIND & COSMOS: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False", Oxford University Press, Oxford, New York. The book did cause an uproar amongst physicists and philosophers, but despite many negative recensions, I have not seen any serious argument against the neo-Vernadsky criticism of a "gaping chasm".

Chemical reactions produce large molecules but do not provide adaptation. Furthermore Neo-Darwinistic laws, including natural selection and the genetic code depend on causal forces and teleonomic laws (see Mayr for definition) and moreover, causality is needed to instigate adaptation. Therefore physics cannot rule out either causality, despite their absence on the fundamental microscopic level, nor progressions that rely on encoded processes. By indiscriminately ruling out intentionality one risks “throwing out the baby with the bath water”.  

An extension of the picture, contained in Rosenberg's quote, is necessarily needed in order to rigorously contain adaptability in general and the genetic code in particular, including its more subtle variations, as closed or open programs, mapping various evolutionary situations, like for instance those for insects or humans.

I have voiced an opinion, based on my professional life as chemical physicist. If some of you want to down vote this without discussion and arguments, please reconsider providing me with your insights or otherwise stay away from RG!

I would add in that there seems to be evidence, from the fringes of psychology, that mind seems to be independent of the material realm.  If this is so, then it introduces a new factor into how evolution might have occurred.

Here I would like to share with you a recent article that is related with probability calculus, evolutionary chaos, mathematical modeling and terraforming, among others. It also demonstrates through nonlinear evolutionary processes, the uniqueness of life and mankind in the universe.

Article Evolution through the stochastic dyadic Cantor Set: the uniq...

I like Andreas Wagner's book The Arrival of the Fittest on this topic. 

And now for some comic relief?

There might be one or two of you on this list, elderly enough to think the publication below is funny. 

If not, carry on as you were.

Nick Thompson

Article Alphabet Soup

Read Michael Behe's novel book "Darwin Devolves". He explains what math can and cannot do. You will find out that random genetic changes are unable to even evolve a single disulphide bond. Geneticists John Sandford's book is also clear about it.

The gap in our understanding is, of course, slavedom to materialisms...although we all know since 1953 that biology is grounded in information, i.e. an immaterial entity.