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Why doesn't evolution converge on perfection?

Why doesn't evolution converge on perfection?


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I got to know about an organism called "Tardigrade(water bear)" which is an extremely hardy organism and can survive in most conditions.

My question is that if the aim of life in general is to ensure the continuity of the species, why have we not simply stayed as tardigrades? it seems like they are the perfect candidates for survival purposes- ensuring(to a degree) that the species does not get wiped out as easily as dinosaurs.

Does that mean that life has a more different incentive--not to just only survive? or it doesn't have any? Could this be the reason of our incapability to make a superhuman intelligence, because our imitation of learning is to reach a certain objective when life does not have any distinct goal? Or am I missing a key point here?

BTW I am an amateur in Machine Learning where we basically try to mimic the learning of phenomenon of nature through 'evolution'. So I would appreciate answers with minimum of abbreviations and as simple as possible :)

Edit:
I am overwhelmed by the response I have received but seeing the answers and communincations, I have inferred that my question may be very basic and vague to biologists. The person who can answer would be the one who has studied both subjects(Deep learning and Evolution). But even then I thank you all for devoting you precious time to attend to my question. Cheers! :)

Also I wonder if there is some paradox somewhere here - in Machine Learning when we simulate some environment the agent, just like evolution figures how to survive it. But when more factors are present, the intelligence doesn't increase after a certain point. Could this Thus be that there is something ethereal unexplainable by science (like soul) which actually gives us a more-than-enough complex brain to further increase our intelligence? Or is this a baseless thought?


The key point you're missing is that perfection is a variable, or perhaps more accurately, a function of many variables that depend on environmental factors and the actions of other species. Even tardigrades have evolved a multitude of different species*, suited to different environments and lifestyles. And apparently they don't do all that well in hot water: https://www.nature.com/articles/s41598-019-56965-z

A creature that evolves to be close to perfection for one set of environmental variables can be seriously mal-adapted to a different set. An albatross, for instance, is very close to perfection - that is, well adapted - to its niche as a creature that flies over oceans, while a dolphin is likewise close to perfection** for an air-breathing creature that lives in that ocean. But either would die in short order in the other's environment, and neither is as well-suited to desert life as a camel.

As for the really unrelated question of why we don't know how to make a "super-intelligence", we don't even know how intelligence actually works, as you should know if you've studied the field. On current evidence, intelligence, at least of the tool-making sort that some humans display, doesn't really seem to be a trait suited to long-term survival.

*About 1150, per Wikipedia: https://en.wikipedia.org/wiki/Tardigrade

**So much so that their basic body plans have been repeated throughout evolution: e.g. ichthyosaurs and marine pterosaurs. There are numerous other examples of such convergent evolution: https://en.wikipedia.org/wiki/Convergent_evolution


My question is that if the aim of life in general is to ensure the continuity of the species

That is not the aim of either life or evolution. Rather individuals have the goal of surviving and genes have the aim of replicating themselves. Individuals that survive get a chance to replicate their genes.

As for why all other organisms that are not ceased existing to make room for more Tardigrades, see above points.


I'm sure you understand natural selection. But there are many different forms of evolution (well 4 main ones). One is based on absolute chance. For example dinosaurs were just unlucky when the asteroid struck; it wasn't as if they weren't adapted. This is called gene drift. What I'm trying to get at is that there is less than one variable that affects evolution, leading to variety.

Another example within natural selection; the food chain. We start off with all producers. One producer becomes a consumer by a genetic mutation. The producers aren't reacting to this because they never needed to, so they get picked off one by one until more adapt to either defend or become secondary consumers (consumers that eat the original). There you go; multiple different types of insects, reacting in response to each other. Assuming an unchanging environment and only natural selection is at play, one could predict that they'll end up in an endless loop of evolving from one state to another to react to each other and going back to their original state (though in real life the environment will change preventing this).

As a side note for your coding; you may want to consider changing the environment at random every so often.

In short: you can't reach a single organism due to interference with other animals and other methods of evolution.

Technically; the aim of a being biologically isn't to survive, but for them to reproduce and pass on their genes, hence natural selection; a small but important discrepancy to make, Our incapability to make a superhuman intelligence has got nothing to do with our biology. Humans are able to cast aside anything to do with their natural emotions, hence a computer doesn't take these into account. The reason we can't have a superhuman intelligence is because we simply don't have the knowledge of human psychology, and the technical ability to make one.


Why evolution do not converge on perfection? I see two main reasons:

First: the "life problem" configuration change in time, so the perfect living being (let's called it global minima) should change over time too. Second: As the "life problem" have several dimensions and the level of complexity is huge, there's no guarantee for the existence of that global minima. All the living organisms then represents near local minima solutions, that evolve over time, like solutions in a evolutionary optimization algorithm.

Why we don't evolve to a superhuman intelligence? I can tell: Who said it doesn't? Maybe in a future there will be super-intelligent-human-like living beings.

One key point is that the intelligence that allow us as a specie to survive and modified our environment do not play against us.


Why doesn't evolution converge on perfection? - Biology

Evolution is a cornerstone to learning about biology. It is about life and about change. Life is always changing. Change is occurring to every living thing on earth, but it is not limited to individuals. Evolution is a much more vast concept because it includes populations of every species on earth.

The following lab is my work: [Miranda Lee]

Topic 1: Identifying the Ecomorphs

For each species of Anole, I used the images to determine the ecomorph of each species. I used clues from body shape, color, and habitat.

Species Body Shape Color Habitat Ecomorph

Table 1. My observations of anole characteristics.

Anolis allisoni- trunk crown
Anolis angusticeps- twig
Anolis distichus- grass bush (or maybe trunk ground)
Anolis equestrus-trunk crown
Anolis grahami-trunk
Anolis gundlachi- trunk ground
Anolis lineatopus- Trunk ground
Anolis occultus- twig
Anolis pulchellus- grass bush
Anolis valencienni- twig

Topic 2: Adaptive Radiation and Convergent Evolution

1. In your opinion, what selective factors must be the same (or sufficiently similar) in order for

Anole evolution to converge independently into the same ecomorphs on each of the four

List at least four such factors and write them in your lab notes.

1. The supply of food has to be the same.
2. The veggitation has to be the same. Trees need to be the same so the Anolis can have the same habitat.
3. Populations have to be the same because if they are to many they will have an unbalance with food and houseing supply and kill each other off and if there is to little then they won't find mates as easliy to breed.
4. Preditors have to be the same so they all develope the same defense mechanisms.

2. The South American mainland has very different ecological niches than the islands we are

studying. The mainland anoles have very different morphologies than island Anoles. Does this

information support the theory of evolutionary convergence of anole ecomorphs?
Yes this information supports the evolutionary convergence of anole ecomorphs.

3. What does it say about the requirement for similarity of environmental conditions?

This says that for things to evolve equally they all need to have similar outside forces making them evolve in the same direction.

Compare each ecomorph to the next ecomorph to evolve on the tree and record your observations

1. How close are their ecological niches to each other?

The phylogenies that are most similar are the places that are geographically closest to each other.

2. What do you think is the evolutionary significance of the location of the ecomorph on the tree?

The closer the places the more similar the envioronment was for the Anolis to evolve. They has similar things pushing them in similar directions.

3. Repeat the annotations and niche comparison with all four island phylogenetic trees. Observe


Why evolution isn't perfect

Most of the time, evolution seems to do a pretty good job of turning out animals with adaptations that help them survive and thrive. But sometimes it doesn’t entirely seem to make sense.

One misconception about natural selection is that, over time, evolution ‘selects’ the features of an organism that are most perfectly suited to its environment. The misunderstanding may be partly due to the term ‘natural selection’ itself, which conjures up parallels with, say, a dog breeder ‘selecting’ for desirable traits in their animals. In fact, nature isn’t actually ‘selecting’ anything—natural selection is a process, not a conscious force.

‘Selecting’ traits for dog breeds is a very different process to natural selection. Image adapted from: Jelly Dude / Flickr CC BY 2.0

There are good reasons why the process of natural selection may not always result in a ‘perfect’ solution. Firstly, selection can only act on the available genetic variation. A cheetah, for example, can’t evolve to run faster if there is no ‘faster’ gene variant available.

Secondly, the body has to work with the materials it already has. It can’t make something out of nothing—that’s why winged horses are the stuff of myth.

Evolution also has to work with the developmental patterns established in distant ancestors, and the results sometimes seem very strange. For instance, you’d think it’d make most sense for the nerve that goes from the voice box to the brain in a giraffe to take the most direct route—a length of around 10 centimetres. But because the giraffe’s body plan was established in an ancestor that had no neck, the nerve goes all the way down the neck, around the heart and back again—a distance of four metres!

Sending a nerve impulse from brain to voice box (via the recurrent laryngeal nerve and vagus nerve) in a giraffe involves a lengthy detour past the heart. Image adapted from: Vladimir V. Medeyko CC BY-SA 2.0

Then, of course, there are those times that really leave us scratching our heads. Like, what’s with wings on flightless birds, or eyes in blind snakes? And why do men have nipples? Evolution is all about creatures gradually adapting to their environment, right? And doesn’t ‘survival of the fittest’ mean a move towards better and better adapted creatures? Couldn’t evolution have come up with a better solution? And why don’t these oddities simply disappear?

First, it’s important to recognise that not all of an organism’s features are due to adaptation. For instance, some non-adaptive, or even detrimental, gene variants may be on the same DNA strand as a beneficial variant. By hitching a ride on the same DNA strand as the useful variant, a non-adaptive gene can quickly spread throughout a population. In other words, just because a certain trait is there doesn’t necessarily mean it’s useful.

In addition, some features may simply be a result of chance, spreading through a population via what’s known as ‘genetic drift’. As we’ve seen, DNA in all organisms can be subject to copying errors. Some of these mutations will be harmful, and will probably be eliminated by natural selection. Others, though, will be ‘neutral’: neither harmful nor beneficial. Most of these will die out, but some will spread throughout a population. Although the chance of neutral mutations spreading is very small, genetic drift is nevertheless a significant force, especially in small populations, because of the enormous number of genetic mutations in each generation.

Genetic drift can also result in gene fixation in a population. This occurs when all other possible variations of a gene (alleles) are lost forever, so that only one allele remains available to pass on to future generations. For that particular trait, the lone surviving allele then becomes the only possible variant of that gene.

###some figure caption ##Image adapted from: #Name CC0# --> ##some citation here with a #link# --> This article was adapted from Academy website content reviewed by the following experts: Professor Jenny Graves AO FAA School of Life Sciences, La Trobe University Professor Rick Shine AM FAA Professor of Evolutionary Biology, School of Life and Environmental Sciences, University of Sydney


‘Evolution is aimless’: How else do we explain external testicles?

E volution is a work in progress, so it’s hardly surprising that some of the features it has built into the human body are still far from optimal. And of all those features, one of the hardest to explain is also one of the most conspicuous: external testicles.

From an evolutionary standpoint, after all, testicles are the most important thing about a man — without them, he wouldn’t exist at all. And there they are, just sitting out in the open. Exposed. Vulnerable. What kind of design is this?

Of course, there is an explanation. Human sperm cells develop better at a slightly lower temperature than the rest of our body seems to prefer. Humans aren’t alone in this respect: Most male mammals have testicles that migrate through the inguinal canal during gestation or infancy and eventually take up residence outside the abdominal cavity, suspended in a temperature-sensitive adjustable hammock. This allows the sperm cells to develop at the temperature that’s just right.

But is it really just right? Only if you accept that the ideal temperature is a special fixed property of the universe, like Planck’s constant or the speed of light in a vacuum. Evolution could have simply tweaked the parameters of sperm development so the ideal temperature of its enzymatic and cellular processes was the same as the rest of the body’s processes. Hematopoiesis, the creation of new blood cells, is a close parallel of sperm development in terms of the tissue architecture and cellular events involved, yet bone marrow doesn’t grow outside our body. Nor do ovaries, for that matter.

/>The fact is that there is no good reason that sperm development has to work best at lower temperatures. It’s just a fluke, an example of poor design. If nature had an intelligent designer, he or she would have a lot to answer for. But since natural selection and other evolutionary forces are the true designers of our bodies, there is no one to question about this. We must interrogate ourselves: Why are we like this?

The so-called “argument from poor design” goes back to Darwin himself. Prior to evolutionary theory, most people, scientists included, considered the world and everything in it to be the flawless creation of a perfect God. Of course, the rampant imperfections we can all easily spot called out for explanation and usually invoked a response along the lines of a “fall from grace” or some other such hand-waving. Now that we know that evolution is the creative force of life, we can be free from the expectation of perfection.

But we’re not. Far too often we repeat refrains like “Well, it must do something important or natural selection would have eliminated it,” or “Living things are perfectly suited for their habitats,” or “Evolution doesn’t tolerate inefficiency.” We haven’t really moved on from the creationist mindset that expects to see perfection in nature.

The reality is that evolution is aimless, natural selection is clumsy, and there’s no such thing as being perfectly adapted. Our bodies are a mishmash of compromises forged in different eras and by survival forces very different from the ones we now face. Evolution can work only with the bodies that we have, as they are, and can achieve “progress” only through the slightest tweaks and tugs. Even more frustrating, the selective forces themselves are constantly changing due to the dynamic nature of environments and ecosystems.

External testicles are just such an example. There are competing theories on how this strange quirk came about. Perhaps the testicles were escaping the newly warming abdomen of early mammals. There are other, more esoteric hypotheses as well, none of them perfectly satisfying, all of them potentially contributing a kernel of truth. In the end, it doesn’t really make sense, but, well, there they are.

In addition to the obvious danger of designing such important organs without any protection or even padding, external testicles introduce additional problems for mammals. One in four men will develop a hernia in their groin, 10 times the rate of women, precisely because of a weakness in the abdominal wall left from the migration of the testicles out of the abdomen. Surgical repair is relatively straightforward, but surgery is a relatively new invention in the history of our species. While only a small percentage of these hernias become life-threatening, given how common they are, hernias have killed untold millions over the ages.

The interesting evolutionary questions don’t end with the origin of external testicles. How they got there is one question what has happened since they got there is another, and we can actually get some answers to that question. While lots of physical variation is selectively neutral, there is reason to believe that conspicuous testicles served additional purposes for their bearers. Perhaps there was a sexual selective advantage in advertising testicles prominently, especially in creatures for whom sperm competition is important. If you got ’em, flaunt ’em.

While humans have relatively modest testicles, our closest relatives, the chimpanzees, harbor comparatively enormous ones, around three times the size of ours even though our overall body weight is similar. What does this tell us? Perhaps the large testicles indicate that male chimpanzees engage in sperm competition, in which the males who create and deposit the most sperm are rewarded with the most offspring. But sperm competition would exist only if the chimps, particularly the females, have sex with multiple partners. In a monogamous arrangement, there would be no advantage in having big testicles and lots of sperm.

And biologists have noticed that when choosing male sexual partners, female chimps prefer those with large testicles. Why? If we assume that testicle size is at least partially controlled by genetics, the female’s reproductive choices influence the traits of the children she will bear, including their genitals. If she chooses a mate with big balls, her sons will have big balls, and if big balls help him have more offspring, she’ll get more grandchildren. It is therefore in her reproductive interest to pursue attractive mates, because they’ll lead to attractive children, and that will boost her genetic legacy. This is known as the “sexy son” hypothesis.

O f course , human testicles are just one glaring example of the quirks that demonstrate how imperfect evolution can be. No sane engineer would design a body with such a bent back, weak knees, and nasal sinuses that have to drain upward. We fail at synthesizing basic vitamins, our immune cells frequently attack our own bodies, and our DNA is mostly gobbledygook. This is not good design.

While the flaws themselves demonstrate the random, haphazard way that evolution works, even more interesting are the backstories of each flaw. We don’t make vitamin C because a primate ancestor already had plenty of it served up right there in its environment. Our sinuses are a mess because evolution smooshed the snouts of monkeys into a more flattened face than other mammals — and then, for reasons we don’t fully understand, humans developed still flatter and smaller faces.

These are not simply obscure academic issues. Our inability to make vitamin C caused the death of millions of our forebears from scurvy. Poor drainage in our meandering sinuses causes frequent and painful infections. We are evolved to survive and reproduce, but not necessarily to be healthy, comfortable, or happy.

Even our powerful minds, supposedly our crowning achievement, are anything but perfect. The biggest threats we now face are purely of our making. Because evolution does not make long-term plans, neither do we: We jump to conclusions, think only of the short term, ignore evidence we don’t like, and fear and despise those who are different from us. And unlike external testicles, which are merely inconvenient, these are flaws that could one day prove fatal to our imperfect species.

Nathan H. Lents is professor of biology and director of the Macaulay Honors College at John Jay College, part of the City University of New York. He maintains the Human Evolution Blog, writes for Psychology Today, and hosts the podcast “This World of Humans.” Besides his new book, he is the author of “Not So Different: Finding Human Nature in Animals.” Follow him on Twitter @nathanlents

This article was originally published on Undark as Evolution’s Worst Mistake? How About External Testicles? and has been republished here with permission.


Is evolution really essential for biology?

The following email was received from university professor Richard Meiss concerning the debate Clash Over Origins in which CMI&rsquos Dr Carl Wieland debated University of Georgia professor Mark Farmer. Dr Jonathan Sarfati replies.

I read with some interest the text and annotation of your debate with Dr Mark Farmer. While I could raise many points, I will confine myself to the passage quoted below:

&lsquoHas the evolutionary paradigm been the great benefit to mankind that is claimed? MF quoted Dobzhansky as saying how important it is to biology. However, Dr Marc Kirschner, founding chair of the Department of Systems Biology at Harvard Medical School states: &ldquoIn fact, over the last 100 years, almost all of biology has proceeded independent of evolution, except evolutionary biology itself. Molecular biology, biochemistry, physiology, have not taken evolution into account at all.&rdquo (quoted in the Boston Globe 23 October 2005). For the Philip Skell quote cited by CW, see Why Do We Invoke Darwin? Evolutionary theory contributes little to experimental biology.&rsquo

Here you have lifted a quote (I suspect to engage in a little bit of &lsquoarguing from authority&rsquo)

As Dr Skell answered in a reply to critics:

&lsquoComparative physiology and comparative genomics have certainly been fruitful, but comparative biology originated before Darwin and owes nothing to his theory. Before the publication of The Origin of Species in 1859, comparative biology focused mainly on morphology, because physiology and biochemistry were in their infancy and genomics lay in the future but the extension of a comparative approach to these sub-disciplines depended on the development of new methodologies and instruments, not on evolutionary theory and immersion in historical biology.&rsquo



Again, how was it that pre-Darwinians managed OK without it, as Dr Skell argues? Italian paleontologist and structuralist Prof. Roberto Fondi of the University of Siena argues that Darwinism was a dead end, so it would be much more fruitful to return to the pre-Darwinian morphology of Aristotle, Linnaeus, Cuvier, and Goethe (see clip, right, about five minutes in). 1

Even if you were right about &lsquouseless factoids&rsquo, design could still be a better inference from the specified complexity of life. Similarly, the pagan chemistry of the ancient Greeks had only four elements the Father of Chemistry, the creationist Robert Boyle, realized that there were many more. It took centuries before this was unified by Mendeleyev then explained by modern atomic theory. So a more complex theory can be the right one if it explains the specific data correctly, even if it seems to have less unity, for the moment.

It&rsquos also notable that evolution has plenty of anomalies itself. E.g.

    Common structures that can&rsquot be explained by common ancestry are called homoplasies, and are common in the alleged transitional series. But appeal to homoplasy is really explaining away evidence that doesn&rsquot fit the paradigm, and indeed such explaining away is ubiquitous. One paper admitted:

Homoplasies are said to be the result of &lsquoconvergence&rsquo or, increasingly commonly, caused by &lsquolateral gene transfer&rsquo. It is no less vacuous to explain them by a common designer.

However, we support not just &lsquomere design&rsquo, which might be vulnerable to a charge of &lsquouseless factoids&rsquo. Rather, we support a particular subset of ID: the biotic message theory, as proposed by Walter ReMine in The Biotic Message. That is, the evidence from nature points to a single designer, but with a pattern which thwarts evolutionary explanations.

Further, we support a subset of that, that the designer is the God of the Bible. And in this model, and indeed to most cultures that have ever existed, common features, whether homologous or homoplastic, would have brought honour to the Creator and would also indicate the Creator&rsquos authority over and mastery of His creation (see &lsquoNot to Be Used Again&rsquo: Homologous Structures and the Presumption of Originality as a Critical Value).

OK, what molecular biological discoveries would be invalidated if we really didn&rsquot come from a single cell that itself came from an inorganic source?

This might have been to his advantage, in that he could look at the subject with fresh eyes. I.e. a leading scientist in his field hears the mass hysteria about how abandonment of goo-to-you evolution would lead to the end of science, and a return to the &lsquodark ages&rsquo (which modern historians point out were actually not so dark).

And he probably could see through the common equivocation, where any change was called &lsquoevolution&rsquo. Then a bait&rsquon&rsquoswitch trick was pulled where this word was also equated with goo to you. These shell-gamers hope their audience won&rsquot realize that the cited changes are actually going in the wrong direction for goo-to-you evolution (that&rsquos if they even grasp this elementary point themselves).

More likely, he could see the fallacies invoked more clearly. E.g. many claim examples of natural selection as a proof of evolution, whereas creationists discovered natural selection before Darwin, and it is an important part of the Creation model.

Some examples are evolutionary propagandists claiming that creationists could not cope with &lsquoevolved&rsquo antibiotic resistance, although the changes have nothing to do with turning bacteria into biologists (see Anthrax and antibiotics: Is evolution relevant?). Another common &lsquoproof&rsquo is sickle-cell anemia, although one of the world&rsquos leading experts on the disease firmly rejects this. Still another is Darwin&rsquos finches, where a cyclical variation in beaks is alleged to prove goo-to-you evolution, and the peppered moths which at best showed natural selection in action and at worst was based on staged photos.

Dr Skell may also have been rightly annoyed at the misleading examples in text books, such as Haeckel&rsquos forged embryo diagrams and implications that the Miller&ndashUrey experiments proved chemical evolution. And after that, shooting the messenger for pointing out these errors.

Related to that might be a good memory for the evidence he may have been taught that is no longer believed even by the evolutionist. I&rsquom not that old, and remember being taught in high school that Ramapithecus was a human ancestor (now regarded as an Orangutan ancestor) as well as the textbook errors above. Derek Ager remained an evolutionist, but admitted:

He may have also seen direct evidence how evolutionary presuppositions have harmed research, e.g. dismissing DNA that doesn&rsquot code for proteins as &lsquojunk DNA&rsquo, whereas it&rsquos this term that should be junked:

So even if you were right, you can&rsquot blame Dr Skell for thinking that the evolutionists have cried wolf far too often.

This is elephant hurling. There is no evidence that the lay audience of evolutionists is any better qualified. Indeed, our support groups (volunteer auxiliaries) comprise a number of scientists highly qualified in these disciplines.

And we are not sure why you bring up chemistry, since the origin of life by chemical evolution remains an intractable problem for materialists. But this doesn&rsquot stop them accepting a naturalistic conclusion a priori by (blind) faith, and then spending millions of taxpayer dollars desperately trying to find evidence. However, this reminds me of an apostate geologist critic who claimed that I (a Ph.D. chemist) don&rsquot understand simple chemistry.

Actually, we make much use of real science, which belongs to everyone regardless of who discovered it, and show how the data best fits a biblical creationist perspective.

This presupposes that creationist sources are not legitimate scientific literature, which is of course begging the question. And the cited creationist sources always cite primary sources that are from journals that evolutionists recognize.

That has indeed happened. But then the establishment punishes said reviewers (see The Smithsonian/Sternberg controversy) or overrules them on ideological grounds (see Chemists in stew about intelligent design). So it is more common for creationists to be less obvious about their conclusions (see some of the papers documented in Do Creationists Publish in Notable Refereed Journals?), or to bypass the censorship completely in peer-reviewed creationist journals.

Hmm, &lsquopeer review&rsquo is merely an excuse to reject creationist arguments, as pointed out in a previous feedback, because some of them break the &lsquorule&rsquo that science must be materialistic. It really boils down to another stipulative definition with all that entails about circularity:

Creation isn&rsquot real science because it isn&rsquot peer-reviewed.
Creation isn&rsquot peer-reviewed because it isn&rsquot real science.

But peer review does have the merit of passing the Piltdown Man and Hwang Woo-suk&rsquos embryonic stem cell claims &hellip Also, while our Journal of Creation and even Creation magazine are peer-reviewed, it would be worth reading the interesting article Is Peer Review Broken?. 5

You will probably get a lot of mileage out of the DVD of the debate&mdash the choir desperately wants to be preached to.

What about Dr Farmer&rsquos choir? This is a tacit admission that Dr Farmer&rsquos preaching will not be as effective when opposition is actually allowed. And just look at the choir just lapping up the atheistic propaganda of the eugenicist Clinton R. Dawkins!

Yes, we do know that, as you say&mdashyou must have been reading our site more than you let on )

Yes, that would be nice. So why don&rsquot evolutionists actually allow this?


Convergent Evolution: A Better Explanation

An international team of scientists working with a certain kind of butterfly in Panama was faced with a question: How could “pairs of clearly unrelated butterflies from Peru to Costa Rica evolve nearly the same wing-color patterns over and over again?”[1] Typically, evolutionists explain this phenomenon away with an empty phrase: “butterflies can evolve along separate and different paths to arrive at the same color pattern, a process called convergent evolution.”[2] This answer requires a suspension of disbelief. How can different species take two very different genetic paths – which would require many major genetic differences – and yet arrive at the same end result?

The “convergent evolution” solution fell apart in a study on Heliconius butterflies published in Current Biology. The Smithsonian Tropical Research Institute remarked that the discovery “forever changes the way evolution is understood.”[3] The finding that motivated this remark is as follows:

although natural selection channeled phenotypic convergence [i.e., outward appearances were similar], divergent developmental contexts between the two major Heliconius lineages opened different developmental routes to evolve resemblance. Consequently, even under very deterministic evolutionary scenarios, our results underscore a surprising unpredictability in the developmental paths underlying convergence in a recent radiation.[4]

Natural selection can, in other words, cause two animals to converge so they look alike (the process called “convergent evolution” noted above), but it can take very different genetic paths to reach that goal. It’s as if two balloons can leave Detroit at the same time, moved by the same wind, but one goes east, the other northwest and they both end up in Paris at the same time. How can this be considered possible? The review uses word salad to basically restate their faith in natural selection’s ability to work miracles.

Evolution is often viewed as a highly contingent process, where chance mutations and random genetic drift affect future outcomes. Nonetheless, there are many cases across branches of the tree of life where different species have evolved remarkably similar solutions to common environmental challenges. Such convergence provides some of the most compelling evidence of the power of natural selection to shape phenotypic diversity in highly deterministic ways. Over the past several decades, numerous studies have examined how convergent change is achieved.[5]

The article concludes, “The broad consensus emerging from these studies is that the path taken by evolution is often repeatable among closely related species but becomes more unpredictable when species are deeply divergent.” In other words, neither natural selection, nor convergent evolution, can explain the final results the study found. This study has eloquently shown that classical evolution theory has a major problem. My conclusion is that convergent evolution, although widely accepted, is wrong.

Professor Doolittle once said that convergence claims are confusing for several reasons, one of which is that often “not enough care is taken to state exactly what kind of convergence one has in mind.” He adds that evidence of “genuine [genetic] sequence convergence has yet to be made.”[6] Genetic sequence convergence is where genetic comparisons show close similarity. What was found in the butterfly study was major genetic differences although the genes for wing color patterns were close to identical.

The authors of the Current Biology paper compared genes between unrelated Heliconius butterflies that nevertheless ended up looking uncannily similar. This undermines the whole convergence argument. There was no genetic convergence and, as we do more genetic comparisons, we will no doubt find many more examples of lack of evidence for genetic convergence in cases where “convergent evolution” has been the consensus explanation. Although claims of convergent evolution are common, even ubiquitous, their identification, interpretation, and explanation are controversial. This line of research will make them even more controversial.[7] Genetic comparisons may well falsify the general theory of convergence.

Why Convergent Evolution Does Not Explain Similarities

Darwinists face a clear and formidable question: how can two animals, with very different ancestries, evolve to become almost identical? It is no small problem. Evolutionists waved it away with the hands of the clock, by claiming gradual evolution takes a long time. Convergence moves slowly as the two species move towards the same goal of becoming more alike as time flows forward. Wikipedia lists over 300 examples of convergent evolution.[8]

Thylacine, or Tasmanian wolf (Wikimedia Commons)

An amazing example of unrelated similarity is the marsupial Tasmanian wolf (Thylacinus cynocephalus) which strongly resembles the placental wolf (Canis). Evolutionists claim that the Tasmanian “wolf” is believed to have evolved in Australia, and the placental wolf in North America. They evolved separately along different paths from very different ancestors to coincidentally end up very similar.

The Tasmanian wolf is sometimes called the Tasmanian tiger. It looks much like a dog, but has stripes on its back like a tiger, and resembles a large cat, a fox, or a wolf. It was once thought extinct, but some recent sightings have been reported in the news. This animal complicates the convergent evolution narrative because of its similarities to three animals.[9] Like the platypus, another Australian marsupial, it seems like a mosaic of multiple animals.

Thylacinus cynocephalus means “pouched animal with a dog’s head.” The main issue involves their reproductive styles, which are totally different. One is a placental mammal, the other a marsupial. And yet this marsupial’s head and the placental dog’s head have very similar skull morphology. Their resemblances in overall shape, locomotory mode, feeding and foraging are also all very similar. Both also have large canines and grinding molars. The behavior and lifestyles of the North American wolf and the Tasmanian wolf are very similar. The only answer evolutionists can give is “convergent evolution,” an empty phrase masquerading as an explanation.

The placental wolf and the marsupial Tasmanian wolf are actually more similar to each other morphologically than a St. Bernard is to a chihuahua. When the Placental wolf and Tasmanian wolf are examined side by side by experts, differences can be seen, but most of the major skull traits and their overall shape are almost identical. “Convergence” attempts to explain away a serious dilemma for Darwinism, namely, how could two animals that are so far apart on the evolutionary tree, and must have diverged from a common ancestor eons ago, end up so similar in so many critical aspects today?

Some biologists have effectively argued against the convergent evolution theory for very good reasons. A major complaint is that it acts as like a post-hoc armchair explanation. Another is that it lacks a mechanism. Another is that it lacks historical evidence. We have no fossil record showing the evolution of the placental wolf from some hypothetical ancient ancestor animal in North America. Nor do we have evidence of the evolution of the Tasmanian wolf from some hypothetical ancient ancestor in Australia. We just know from the evidence that lots of placental wolves live in North America and lots of Tasmanian wolves live in Australia and, in general, no fossils of marsupial wolves are found in North America and no fossils of the placental wolves are found in Australia.

If large numbers of Tasmanian wolf fossils were found in North America beside living placental wolves, evolutionists would be ready with a different story. They could say both evolved here and split off recently, with the former having migrated to Australia. No matter what the facts show, evolution is always the answer.

Another major difficulty with convergent evolution as an explanation for the placental wolf and the Tasmanian wolf is that their common traits are far too similar to have evolved separately from different ancient common ancestors way back in the early Cretaceous, as evolutionists believe. Such a huge time span should have produced far more differences than observed. Many other examples of convergence also show commonalities in so many ways that only experts can see the distinctions.[10] Evolutionary paleontologists often have difficulty determining

whether organisms shared a characteristic because they inherited it from a common ancestor, or because they evolved it separately by convergence. This sometimes makes reconstructing fossil history difficult. Sometimes in the fossil record a species appears to have become extinct then reappears. Is it because the species was rare for a long time, then reappeared in greater abundance (what paleontologist David Jablonski calls Lazarus taxa, because they appeared to rise from the dead), or because another lineage evolved similar features by convergence, and it just looked like a reappearance (what paleontologist Douglas Erwin calls Elvis taxa)?[11]

The theory of convergence has additional problems. “Natural selection” is the Darwinians’ magic wand to explain everything, including convergence, but science should be open to other theories that can explain things. The major difficulty by far with convergence is how random mutations and natural selection could repeatedly generate the same complex designs requiring many genes, sometimes several scores of times. If Darwinists were not so antagonistic to skeptics of their theory, they might be open to evidence of an intelligent Creator using the same design in different contexts.

Convergence Theory Hinders Science

Svante Pääbo, after decades of research, wrote that convergence makes taxonomy difficult. He wrote that the many “examples of convergent evolution was to me a strong message that morphology is often an unreliable indicator of relatedness among organisms.”[12] Professor Lima-de-Faria, in an extensive study of convergent evolution, concluded that the striking similarities in very different life-forms is a “puzzling fact” not explained by Darwinism. Indeed, he believes, similarities between unrelated organisms are a major obstacle for evolution theory.[13] The esteemed evolutionist George Gaylord Simpson stressed that “the phenomenon of evolutionary convergence… is a source of disquiet and precaution to paleontologists and other biologists.”[14]

Some evolutionists try this angle: living in similar environments and experiencing similar selection pressures can produce convergence, they argue.[15] This is called the “adaptationist” theory of convergence. Comparing the adaptationist and constraint perspectives on convergent evolution, evolutionists considered

the more fundamental question about the predictability of evolutionary change. More generally, convergent evolution has long been taken as evidence of adaptation, but some recent workers have questioned the ability of evolutionary biologists to infer the operation of natural selection from the phylogenetic pattern.[16]

Mindless Environments Cannot Force Convergence

There is no necessary connection between the environment and convergence. Environments of “convergent” animals are often very different. Except for opossums and their relatives, marsupials are now found only in Australia and New Zealand. The environments of North America and Australia are very different in climate, terrain, and, especially, in the life-forms inhabiting the land, and yet both America and Australia have opossums.[17]

Heliconius wing patterns not by chance but by genetic sharing. (Wikimedia Commons)

Conversely, environments of unlike animals are often quite similar. No reason exists to believe similar environmental demands could evolve two very different precursor animals to converge into animals with similar traits. Nor does any direct evidence exist that even very similar environments will evolve different animals to increasingly resemble each other until they become, not just superficially identical, but in many ways, close to physiologically identical. In conclusion, convergence theory has launched many disputes in the past between evolutionists, and new research has only added to their headaches.

Sharing: A Much Better Explanation

Possibly due to the inadequacy of convergent evolution, another (and much better) explanation has been offered for convergence: shared information. Animals can pass genes back and forth in a process known as introgression, defined as “the introduction of genes from one species into the gene pool of another species, occurring when matings between the two produce fertile hybrids.” In the case of the Heliconius butterflies, the researchers are claiming that rampant introgression has occurred.[18]

Another example shows up in the human gene pool. Geneticists writing in a preprint in bioRxiv on November 15 found that “Neanderthal introgression reintroduced functional ancestral alleles lost in Eurasian populations.” Nothing new evolved the information was “reintroduced” to Eurasions through introgression.

Even so, explaining the variety by the exchange of genes due to interbreeding between genetically divergent individuals does not solve the evolutionary origins problem. What needs to be explained is the origin of the functional genes that are passed around by introgression. As any dog breeder knows, the exchange of genes produces an enormous amount of variety. Hollingshead opined: “On a grand scale, the findings provide evidence that the model of an evolutionary tree first famously drawn by Darwin may need some adjusting.”[19]

Actually, this is what creationists have been saying for decades: a great deal of the variety in the natural world is the result of sharing of genetic information, not emergence of new genetic information by random mutation and natural selection. Sharing of pre-existing genetic information can occur by several methods, including horizontal gene transfer, retrovirus insertions, hybridization, interbreeding and introgression. Creation taxonomists organize life by “created kinds” (baramin), within which a good deal of horizontal diversification and genetic sharing can occur. For example, the cat kind includes lions, cheetahs, domestic cats, etc. – a total of 30+ living species and a number of extinct ones. These all came from the original pair of cats, Purdom and Hodge argued in a 2008 paper.[20]

With evolution a theory in crisis, particularly when it comes to convergence, openness to alternative explanations is in order.

[1] Is Evolution Predictable? Butterflies take different paths to arrive at the same color pattern. Smithsonian Tropical Research Institute, 14 November 2019. https://stri.si.edu

[4] Carolina Concha, et al., 2019. Interplay between Developmental Flexibility and Determinism in the Evolution of Mimetic Heliconius Wing Patterns. Current Biology, 29: 1-14, December 2 DOI: 10.1016/j.cub.2019.10.010.

[6] Doolittle, R. 1994. “Convergent Evolution: The Need to be Explicit.” Trends in Biochemical Sciences, 19(1):15-18, p. 15.

[7] Losos, J. B. 2011. “Convergence, Adaptation, and Constraint.” Evolution, 65(7):1827-1840.

[8] Wikipedia: List of examples of convergent evolution. https://en.wikipedia.org/wiki/List_of_examples_of_convergent_evolution.

[9] Woodward, Aylin. The Tasmanian tiger is thought to have gone extinct in 1936, but mysterious sightings suggest the creature might still be out there. https://www.businessinsider.com/tasmanian-tiger-may-not-be-extinct-sightings-pictures-2019-11.

[10] Simpson, George. 1980. Splendid Isolation: The Curious History of South American Mammals. New Haven, CT: Yale University Press.

[11] Rice, Stanley. 2007. “Convergence,” pp. 89-93 in: Encyclopedia of Evolution. New York, NY: Facts on File, p. 93.

[12] Pääbo, Svante. 2014. Neanderthal Man: In Search of Lost Genomes. New York, NY: Basic Books, p. 66.

[13] Lima-de-Faria, A. 1988. Evolution without Selection: Form and Function by Autoevolution. Amsterdam, Holland: Elsevier, p. 271.

[14] Losos, J. B. 2011 Simpson, 1980, pp. 12-13.

[15] Milner, R. 1990. The Encyclopedia of Evolution. New York, NY: Facts on File.

[16] Rice, 2007 Losos, 2011, p. 1872.)

[17] Johnson, D. H. 1955. “The Incredible Kangaroo: Australia’s Famous Marsupial Sits on Its Tail, Fights Like a Man, Bounces Like a Steel Spring, and Graces a Coat of Arms.” The National Geographic Magazine, 108(4):487-500, p. 489.

[18] Reuell, Peter. 2019. A Clue to Biodiversity. https://news.harvard.edu/gazette/story/2019/10/gene-flow-between-butterfly-species-offers-clue-to-biodiversity/ Nathaniel B. Edelman. 2019. Genomic architecture and introgression shape a butterfly radiation. Science. Science 01 Nov 2019. 366 (6465): 594-599. Online at https://science.sciencemag.org/content/366/6465/594.full.

[19] Hollingshead, Todd. 2019 Analysis of butterfly genomes reveals answers to complex evolutionary history questions. https://lifesciences.byu.edu/researchers-break-down-20-whole-genomes-of-perplexing-butterfly-to-find. October 31.

[20] Purdom, Georgia and Bodie Hodge, 2008. “Zonkeys, Ligers, and Wolphins, Oh My!” Answers in Depth, Vol.3, pp.71–73. https://assets.answersingenesis.org/doc/articles/aid/v3/zonkeys-ligers-wolphins.pdf .

Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology at several colleges and universities including for over 40 years at Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,300 publications in 12 languages and 40 books and monographs. His books and textbooks that include chapters that he authored, are in over 1,500 college libraries in 27 countries. So far over 80,000 copies of the 40 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.


The Evolution Revolution: Physicist Lee Spetner Shows Why Convergence Challenges Neo-Darwinian Evolution

Many ENV readers might have read, or at least heard of, a well-argued 1996 book by Lee Spetner, Not By Chance. Spetner, who holds a PhD in physics from MIT, has recently published a sequel titled The Evolution Revolution: Why Thinking People Are Rethinking the Theory of Evolution (Judaica Press, 2014). The new book provides some wonderful arguments that challenge common descent and neo-Darwinian explanations of evolution.

Spetner goes through many examples of non-random evolutionary changes that cannot be explained in a Darwinian framework. He covers some of the natural genetic engineering mechanisms reported by James Shapiro, which can modify an organism’s genome during a period of stress. Of course the big criticism of Shapiro’s arguments is that he never explains how those “natural genetic engineering” mechanisms arose in the first place. Whatever the case, these abilities appear to be built-in mechanisms designed to allow an organism to adapt to a changing environment. Spetner comments:

An organism thus has the built-in ability to adapt to a new environment heritably by altering its DNA. These adaptations occur just when they are needed, because they are triggered by an input from the new environment. Since they are triggered by the environment, their occurrence in a population s not rare. They will occur in a large fraction of the population, leading to rapid evolutionary changes — possibly even in one generation! If such adaptive changes had to be achieved by random DNA copying errors (point mutations), they would require long expanses of time, if they could be achieved at all. (p. 49)

Spetner thus proposes what he calls the “Nonrandom Evolutionary Hypothesis” (NREH) where changes in populations occur due to nonrandom processes, as if they are preprogrammed to evolve in certain ways.

One of the best examples he gives for his NREH is the prevalence of “convergent evolution” in biology. He argues that convergent evolution undermines the theory of common descent, and really doesn’t explain anything:

If comparing all possible biological features yields the same tree, then the tree could have some objective reality. Richard Dawkins (2009, pp. 321 ff.) offered what he calls “powerful evidence” for Common Descent based on the (presumed) existence of a phylogenetic tree. … An argument for Common Descent would be helped if anatomical data and molecular data would always lead to the same tree. However, the fact is they don’t. Phylogenetic trees based on different genes are known to give contradictory results. There was hope that the use of whole genomes, or at least large portions of genomes, for phylogenetic studies would resolve those contradictions, but that only made the problem worse.

The lack of uniqueness of the phylogenetic tree is usually explained away by what is called “convergent evolution.” Convergent evolution is the appearance of the same trait or character in independent lineages. It is, however, an invention. It was invented solely to avoid addressing the failure of phylogenetic trees to support Common Descent. There is no theoretical support for convergence, and whatever evidence has been given for it is the product of a circular argument. Richard Dawkins (2010) seems to revel in describing numerous examples of convergent evolution without realizing that any of those examples destroy his case for evolution.

[…]

Convergent evolution is the Darwinists’ lollapalooza. They made it up to keep their phylogenetic tree from falling apart, but they can’t say how convergence happens. As Joseph Keating (2002) wrote in another context, it is no more than a “pseudo-explanation, and may deceive us into believing we have explained some aspect of biology when in fact we have only labeled our ignorance.” (pp. 87-89, 92 internal citations removed)

Spetner goes on to list nearly six pages worth of striking examples of convergent evolution. You’ll have to pick up the book to get the full impact of this, but here’s a brief summary of a few highlights:

  • Similar physical mechanisms are used to transmit sound waves from the ear to the brain in both vertebrates and certain insects.
  • Unrelated frogs from Madagascar and India “converged” on similar morphological, physiological, and developmental traits.
  • Hawaiian honeyeater birds and Australian honeyeater birds look and act very similarly and thus were once classified together, but their DNA shows they’re not closely related and are “a particularly striking example” of convergent evolution.
  • Spetner writes: “Convergence is invoked for evolutionary similarities among the proteins in the venoms found in all animal phyla, including arthropods, cephalopods, and vertebrates.” (p. 95)
  • Spetner explains “The ATPase of the monarch butterfly and of the leaf beetle … are said to have arrived at the same ATPase molecule by convergent evolution.” (p. 96)

These examples are labeled “convergence” and are called “surprising,” “spectacular,” “remarkable,” and “striking.” They are “surprising,” but only under the neo-Darwinian paradigm. Under the NREH, they are not surprising but expected. (p. 145 internal citations removed)

Many other topics are covered in The Evolution Revolution. I highly recommend this short, up-to-date, well-informed, and well-written book for a review of some key, compelling evidence showing that species did not arise through neo-Darwinian mechanisms.


Evolution is Still Not a Theory in Crisis, but Neo-Darwinism Might Be

INTRO BY JIM: We’re often asked how our position of Evolutionary Creation differs from Intelligent Design. That’s a tricky question to answer succinctly, as there is a considerable range of views under each of these positions. At BioLogos, we state clearly that we accept the overwhelming scientific evidence for common ancestry by the process of evolution. We do not, however, commit to a particular scientific account of the mechanism(s) of evolution, because this is still an active area of research in the scientific community. So there will be some diversity of opinion on this among those associated with BioLogos. The Discovery Institute —the most prominent organization advocating for Intelligent Design—has even more diversity in the range of scientific explanations that are accepted, from Young Earth Creationism to acceptance of common ancestry .

Michael Denton is a fellow of the Discovery Institute. From the title of his new book, you wouldn’t expect him to be one of the people there who accept common ancestry, but it appears that he does . It’s hard to read the title, therefore, as anything other than misleading. There is vigorous debate about the mechanisms by which life evolves, with what is sometimes called the “neo-Darwinian” view being challenged from many corners of the scientific community and alternatives such as the “extended evolutionary synthesis” being developed (see for example Michael Burdett’s discussion of the 2014 article in Nature, “Does Evolutionary Theory Need a Rethink?”). But evolution itself is not a theory in crisis. If the Discovery Institute would consistently disseminate to its followers the distinction between the abundant evidence for common ancestry and the remaining debate about the particular mechanisms of evolution, the intellectual distance between EC and ID would quickly diminish. We would welcome such a change. [Editor’s note: this introduction was slightly edited February 17, 2016.]

Michael Denton, Evolution: Still a Theory in Crisis (Seattle: Discovery Institute Press, 2016).

This book is a update to Denton’s 1985 book of the same title (minus the word “still”), but it is an important departure from the earlier work.

We are well aware that book reviewers bring their own biases and beliefs with them as they read. So, because we are convinced this is an important book that needs to be discussed fairly, we will start by owning up to our own worldviews related to the issues covered. We are adherents of Darwinian evolution, and we think that Charles Darwin’s insights underlie all of biological science. By this we mean acceptance of the principle of descent with modification of all life from a common ancestor, through the mechanisms of genetic variation and natural selection. We are also evolutionary creationists, and believe as a matter of faith that life ultimately derives from the divine Creator. We are unconvinced by arguments against Darwinian evolution, including those from young earth creationists and intelligent design advocates. Our worldview did not initially dispose us favorably to a book with this title written by a well-known proponent of ID and published by the Discovery Institute.

Denton describes his own worldview throughout the book as “structuralism”, which is all about the form that matter (including biological matter) takes. This contrasts with “functionalism” (the basis of Darwinism), which is about how things work, including adaptation. His hero is Richard Owen, a pre-Darwin naturalist who wrote extensively on the concept of natural law as the basis for biological forms. Denton takes the pre-Darwinian 19 th -century concept of Types— clades , such as vertebrates and mammals—as his central theme. According to Denton (and Owen), Types are the manifestation of built-in biological laws and what distinguishes them are structural homologs that cannot be explained by either slow, progressive steps (the gradualism of classical Darwinism) or purely adaptationist natural selection. This philosophical view fits well with the standard anti-evolution paradigm of Intelligent Design.

On almost every page, Denton claims that Darwinism is refuted, contradicted, or “stands on sand.” According to Denton, the key hallmarks of Darwinism are a strict adherence to adaptationist functionalism and an insistence on gradualism. Gradualism has long been a focal point of attacks on Darwinism by ID advocates, and is the basis for the irreducible complexity argument.

But at this point, things get interesting, because Denton does not go there. He never mentions irreducible complexity in the entire book. His attack on what he calls Darwinism is presented almost entirely in the words and research of current evolutionary biologists. He devotes a whole chapter to Evo-Devo , and quotes Sean B. Carroll extensively. When he argues (using examples like vertebrate limbs, feathers, flowers, insect legs, or human language) that there is no evidence for stepwise selective mechanisms for major innovative changes that define clades, he quotes Gould, Koonin, A. and G. Wagner, and Pigliucci—not Johnson, Behe, or Dembski.

Denton agrees (as does everyone else) that natural selection is the best explanation for microevolution. Denton expands microevolution to a process that occurs in clades (such as mammals or even vertebrates). But, like the creationists, he argues that macroevolution is a different story and requires an entirely different mechanism to explain the jumps from fins to limbs, or scales to feathers.

And here is where we fully expected to see the phrase “evidence for design” fill in the blank of how such innovations come about, if not by Darwinian natural selection. But that is not what Denton says in this book. Not at all. In fact, the word “design” rarely occurs in the book, and never in the context of any kind of explanation for the origin of a biological form or mechanism. What Denton does say is this:

There is a tree of life. There is no doubt that all extant life forms are related, and descended from a primeval ancestral form at the base of the tree. (p. 112)

Descent with modification implies a pattern of descent through time, where extant forms have descended with modification from common ancestral forms, right back to the last common ancestor of all extant life. But the fact of descent with modification cannot be taken as…. support for any sort of gradualism. [emph. added] (p. 195)

However, my claim that life is an integral part of nature is not an argument for design or a defense of Plato’s cosmology, but an ontological verdict on the fabric of reality… [emph. added] (p 281)

So is Michael Denton saying that evolution (which he calls descent with modification) has occurred from the start of life until the present, and that the complex and innovative structures that mark the major phylogenic branches of the tree of life took place by natural means rather than by special creation or intelligent design? Yes, that is what he is saying. So, you might be asking (as we were), why exactly is evolution “still a theory in crisis”? The answer is that the crisis is all about what so many evolutionary biologists have been saying: neo-Darwinism is not correct. Slow accumulation of random mutations in structural genes just doesn’t cut it when we are talking about innovative variations that give rise to new clades.

Gould said this with punctuated equilibrium . Kimura toppled the adaptationist exclusivity with the neutral theory . James Shapiro (who is strangely absent from the book) has been talking about the very same thing for years, as has Pigliucci, Wagner, Muller, Jablonka, Laland, Newman, and all the others of the Third Way and the Altenburg 16 . Simon Conway Morris (another strange omission in Denton’s list of scientific allies) has turned evolutionary biology around with his demonstration of convergence and constraints on evolutionary possibilities.

So what Denton is proposing here is closer to the Extended Evolutionary Synthesis , which is struggling with neo-Darwinism to be the standard model for evolutionary biology, than to the vaguely crafted, creationist-flavored non-hypothesis of the original ID movement. Denton presents epigenetics, transposition, the emergence of new properties from complex precursors, and (we were happy to see) includes a strong emphasis on the role of gene regulatory networks in the production of innovative structural phenotypes. So, importantly, Denton is not appealing to a creative intelligence in lieu of biological mechanisms, but weighing—as many evolutionary biologists are also doing—the relative importance of natural selection as a driver of evolutionary change.

In this book we find what has been lacking in many ID arguments: the threads of a coherent scientific hypothesis to explain the great question of emergent novelties during evolutionary history. There is no mention of the impossibility of explaining complex and novel biological structures and systems by natural causes or the red herring of statistical improbability. In contrast, Denton constantly stresses that biology is based as much on natural law as is physics. His arguments against gradualism and panadaptationism are biological rather than metaphysical, and are very much in line with those of the Extended Synthesis.

While this is very welcome and we think a great step forward, we admit that the continuous trumpet call of “anti-Darwinism” in the book is grating and gratuitous, and (like the title) could limit the book’s contribution to conversations among Christians on the reality of evolution. Some of the rhetoric comes across as protesting too much. Origin of Species should not be treated as an inerrant text. Of course Darwin made errors, as did Newton, Einstein, and all real scientists in the past and present.

While Darwin did stress the importance of incremental gradual changes, and he did hold that natural selection should be invoked as an adaptationist explanation for all new features, these ideas are not so much errors as overstatements. If we define extreme-Darwinism as the dogma of Darwinian inerrancy, then we can substitute “extreme-Darwinism” for “Darwinism” in almost every instance of its use in Denton’s book. By that small “insertion mutation”, we almost render the entire book fully in line with one mainstream current of evolutionary biology.

Denton’s Evolution (the sequel) is an important book, because it might represent an intriguing and fascinating opportunity for real progress in the sometimes bitter debate about evolution among Christians. That might be an optimistic view, but we are not alone in this idea. Darrel Falk, past president of BioLogos, has written a review of the book for Amazon that reflects our own thoughts quite closely.

In his review, Darrel says:

…Denton’s work is highly embedded in the well-established fact of common descent of all living organisms… Hence if this work does become central to the future of the Intelligent Design Movement it would be great if they would focus in on a coherent theory like that which Denton espouses…

We can only agree that it would be great indeed. We think that Darrel’s enthusiasm stems from the same source as our own optimism that this book represents a potential for a real breakthrough in discussions between evolutionary creationists (EC) and the ID movement. There is nothing that forces EC to adhere to an extreme Darwinian or neo- Darwinian stance, and one of us (SG) has written about the new Extended Synthesis as being the best framework for EC to follow ( Perspectives in Science and Christian Faith , in Press God and Nature , In Press).

Denton’s new book may very well be a catalyst in the eventual reconciliation of two Christian scientific philosophies of the nature of life. If that does happen, we believe it will be a joyful day in Heaven, and we can only say: The Lord be praised!

Sy Garte

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Human Evolution: Gain Came With Pain

BOSTON—Humans are the most successful primates on the planet, but our bodies wouldn’t win many awards for good design. That was the consensus of a panel of anthropologists who described in often-painful (and sometimes personal) detail just how poor a job evolution has done sculpting the human form here Friday at the annual meeting of AAAS (which publishes ScienceNOW). Using props and examples from the fossil record, the scientists showed how the very adaptations that have made humans so successful—such as upright walking and our big, complex brains—have been the result of constant remodeling of an ancient ape body plan that was originally used for life in the trees. “This anatomy isn’t what you’d design from scratch," said anthropologist Jeremy DeSilva of Boston University. "Evolution works with duct tape and paper clips."

Starting with the foot, DeSilva held up a cast with 26 bones and said: "You wouldn’t design it out of 26 moving parts." Our feet have so many bones because our ape-like ancestors needed flexible feet to grasp branches. But as they moved out of the trees and began walking upright on the ground in the past 5 million years or so, the foot had to become more stable, and bit by bit, the big toe, which was no longer opposable, aligned itself with the other toes and our ancestors developed an arch to work as a shock absorber. "The foot was modified to remain rigid," said DeSilva. "A lot of BandAids were stuck on these bones." But the bottom line was that our foot still has a lot of room to twist inwards and outwards, and our arches collapse. This results in: ankle sprains, plantar fasciitis, Achilles tendonitis, shin splints, and broken ankles. These are not modern problems, due to stiletto heels Fossils show broken ankles that have healed as far back as 3 million years ago.

A better design for upright walking and running, DeSilva said, would be a foot and ankle like an ostrich. An ostrich’s ankle and lower leg bones are fused into a single structure, which puts a kick into their step—and their foot has only two toes that aid in running. "Why can’t I have a foot like that?" asked DeSilva. One reason is that ostriches trace their upright locomotion back 230 million years to the age of dinosaurs, while our ancestors walked upright just 5 million years ago.

Turning up the pain threshold a notch, anatomist and paleoanthropologist Bruce Latimer of Case Western Reserve University in Cleveland, Ohio, limped to the podium, dangling a twisted human backbone as evidence of real pain. "If you want one place cobbled together with duct tape and paper clips it’s the back," said Latimer, a survivor of back surgery.

When humans stood upright, they took a spine that had evolved to be stiff for climbing and moving in trees and rotated it 90 degrees, so it was vertical—a task Latimer compared to stacking 26 cups and saucers on top of each other (vertebrae and discs) and then, balancing a head on top. But so as not to obstruct the birth canal and to get the torso balanced above our feet, the spine has to curve inwards (lordosis), creating the hollow of our backs. That's why our spines are shaped like an "S." All that curving, with the weight of the head and stuff we carry stacked on top, creates pressure that causes back problems—especially if you play football, do gymnastics, or swim the butterfly stroke. In the United States alone, 700,000 people suffer vertebral fractures per year and back problems are the sixth leading human malady in the world. "If you take care of it, your spine will get you through to about 40 or 50," said Latimer. "After that, you’re on your own."

Paleoanthropologist Karen Rosenberg of the University of Delaware, Newark, moved beyond pain. As our bodies had to adapt to upright walking and bigger brains, they had to balance both of those changes with the limitations of the birth canal—and allowing enough mothers and babies to survive that the big-brained, upright walking species didn’t go extinct. "Death in childbirth used to be leading cause of death for women in reproductive years." That’s because compared with other primates, humans give birth to babies with larger bodies and brains—on average, human babies are 6.1% of their mother’s body size compared with chimp babies (3.3%) and gorilla babies (2.7%).

Despite the high risks for death and injury in childbirth, our ancestors’ solution to the problem was to give birth with social support. Today, humans rely on culture, often in the form of modern medicine, to change that outcome, using assisted birth with doctors or midwives, for example. One sign of that is that is that caesarean sections account for about 30% of all births in the United States, Rosenberg said.

The point of citing all these problems? Evolution doesn’t "design" anything, says anthropologist Matt Cartmill of Boston University, a discussant on the panel. It works slowly on the genes and traits it has at hand, to jerry-rig animals’ and humans body plans to changing habitats and demands. “Evolution doesn’t act to yield perfection," he says. "It acts to yield function.”


‘Whack-a-mole’ shows evolution doesn’t go for perfection

You are free to share this article under the Attribution 4.0 International license.

Evolution, it seems, is not very good at multitasking, according to new research that involved purposely messing with its delicate machinery.

“I’m fascinated with life, and that’s why I want to break it,” says coauthor Betül Kaçar, an assistant professor at the University of Arizona’s departments of molecular and cellular biology and of astronomy, as well as at the Lunar and Planetary Laboratory, in describing her research.

What may sound callous is a legitimate scientific approach in astrobiology.

“I guess I tend to mess with things I’m not supposed to. Locked in time? Let’s unlock it. Breaking it would lead the cell to destruction? Let’s break it.”

Known as ancestral sequencing, the idea is to “resurrect” genetic sequences from the dawn of life, put them to work in the cellular pathways of modern microbes—think Jurassic Park but with extinct genes in place of dinosaurs, and study how the organism copes.

Kaçar uses ancestral sequencing to find out what makes life tick and how organisms are shaped by evolutionary selection pressure. The insights gained may, in turn, offer clues as to what it takes for organic precursor molecules to give rise to life—be it on Earth or faraway worlds.

In her lab, Kaçar specializes in designing molecules that act like tiny invisible wrenches, wreaking havoc with the delicate cellular machinery that allows organisms to eat, move, and multiply—in short, to live.

Evolution and ‘translation machinery’

Kaçar has focused her attention on the translation machinery, a labyrinthine molecular clockwork that translates the information encoded in the bacteria’s DNA into proteins. All organisms—from microbes to algae to trees to humans—possess this piece of machinery in their cells.

“We approximate everything about the past based on what we have today,” Kaçar says. “All life needs a coding system—something that takes information and turns it into molecules that can perform tasks—and the translational machinery does just that. It creates life’s alphabet. That’s why we think of it as a fossil that has remained largely unchanged, at least at its core. If we ever find life elsewhere, you bet that the first thing we’ll look at is its information processing systems, and the translational machinery is just that.”

So critical is the translational machinery to life on Earth that even over the course of more than 3.5 billion years of evolution, its parts have undergone little substantial change. Scientists have referred to it as “an evolutionary accident frozen in time.”

“We get into the heart of the heart of what we think is one of the earliest machineries of life.”

“I guess I tend to mess with things I’m not supposed to,” Kaçar says. “Locked in time? Let’s unlock it. Breaking it would lead the cell to destruction? Let’s break it.”

The researchers took six different strains of Escherichia coli bacteria and genetically engineered the cells with mutated components of their translational machinery. They targeted the step that feeds the unit with genetic information by swapping the shuttle protein with evolutionary cousins taken from other microbes, including a reconstructed ancestor from about 700 million years ago.

“We get into the heart of the heart of what we think is one of the earliest machineries of life,” Kaçar says. “We purposely break it a little, and a lot, to see how the cells deal with this problem. In doing this, we think we create an urgent problem for the cell, and it will fix that.”

Natural selection whack-a-mole

Next, the team mimicked evolution by having the manipulated bacterial strains compete with each other—like a microbial version of The Hunger Games.

A thousand generations later, some strains fared better than others, as was expected. But when Kaçar’s team analyzed exactly how the bacteria responded to perturbations in their translational components, they discovered something unexpected: Initially, natural selection improved the compromised translational machinery, but its focus shifted away to other cellular modules before the machinery’s performance was fully restored.

“We expected that the hammer of natural selection also comes down randomly, but that is not what we found.”

To find out why, Kaçar enlisted Sandeep Venkataram, a population genetics expert at the University of California, San Diego.

Venkataram likens the process to a game of whack-a-mole, with each mole representing a cellular module. Whenever a module experiences a mutation, it pops up. The hammer smashing it back down is the action of natural selection. Mutations are randomly spread across all modules, so that all moles pop up randomly.

“We expected that the hammer of natural selection also comes down randomly, but that is not what we found,” he says. “Rather, it does not act randomly but has a strong bias, favoring those mutations that provide the largest fitness advantage while it smashes down other less beneficial mutations, even though they also provide a benefit to the organism.”

In other words, evolution is not a multitasker when it comes to fixing problems.

“It seems that evolution is myopic,” Venkataram says. “It focuses on the most immediate problem, puts a Band-Aid on, and then it moves on to the next problem, without thoroughly finishing the problem it was working on before.”

“It turns out the cells do fix their problems but not in the way we might fix them,” Kaçar adds. “In a way, it’s a bit like organizing a delivery truck as it drives down a bumpy road. You can stack and organize only so many boxes at a time before they inevitably get jumbled around. You never really get the chance to make any large, orderly arrangement.”

‘Evolutionary stalling’

Why natural selection acts in this way remains to be studied, but what the research showed is that, overall, the process results in what the authors call “evolutionary stalling”—while evolution is busy fixing one problem, it does so at the expense of all other issues that need fixing.

They conclude that at least in rapidly evolving populations, such as bacteria, adaptation in some modules would stall despite the availability of beneficial mutations. This results in a situation in which organisms can never reach a fully optimized state.

“The system has to be capable of being less than optimal so that evolution has something to act on in the face of disturbance—in other words, there needs to be room for improvement,” Kaçar says.

Kaçar believes this feature of evolution may be a signature of any self-organizing system, and she suspects that this principle has counterparts at all levels of biological hierarchy, going back to life’s beginnings, possibly even to prebiotic times when life had not yet materialized.

The research group is now working on using ancestral sequencing to go back even further in time, Kaçar says.

“We want to strip things down even more and create systems that start out as what we would consider pre-life and then transition into what we consider life.”


Watch the video: Είναι η Εξέλιξη απλά μια θεωρία; (May 2022).


Comments:

  1. Akik

    It goes without saying.

  2. Plutus

    So what is next?

  3. Nikolaus

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  4. Vimuro

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  5. Mal

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