The Tree of Diversification (or why the March of Progress is wrong)

By David Winter 22/02/2012 13


I’m giving a big talk next week – a departmental seminar. It’s the first time I’ve had more than 15 minutes to talk about my research, so this talk will be a little more discursive that my usual.

I study speciation, how new species come into being, and one of the things that I want to emphasise is that speciation hasn’t really entered into the broader understanding of what evolution is.Take the one image that describes evolution in modern society:


The March of Progress, Rudolph F. Zallinger. From Time Life’s book Early Man.

The so called “march of progress” has been used to describe the origin of our species thousands upon thousands of times. But it never happened. Only a few of the species depicted are potential ancestors for humans and many of them were contemporaries to each other (as the original diagram makes clear) so can hardly be different steps along a single evolutionary path. 
To try show what really happened, I’ve redrawn “March of Progress” into the “tree of diversification” – trying to show how the species depicted above relate to each other (parts of this tree are very much up for debate, by the way). Bear in mind, I’m only including the species that are represented in the original graphic, if we were to include all the fossil ape species we know about the tree would be much bushier):


Silhouettes are CC BY-SA by José-Manuel Benitos this image is released under the same license

I think that when you look at it this way it becomes clear that if we want to understand how the organisms depicted in the most famous icon of evoluton came to be we need to focus not just on how changes occur in one lineage, but on how new lineage form and become capable of changing in their own directions. At the moment there are probably 10 million species on earth, and just how they got to be here is surely one of the biggest questions that biology asks us. Speciation and diversification ought to be central to the way we think about evolution.


13 Responses to “The Tree of Diversification (or why the March of Progress is wrong)”

  • DNA has destroyed this concept of simpler life “evolving”. DNA only shows genetic losses in speciation.
    Humans have over 7000 genetic diseases and more every year. This is from mutations. There is no scientific evidence of any form of net positive mutations. Mutations are destructive to already existing and already made species.
    We know that these mutations are causing diseases in humans because we have the PRIOR fit condition in living humans.
    However, every human on earth has genetic defects. No, person is truly healthy because of this.

    • James,

      I wrote a whole post on why we need to think about speciation as an important and different part of evolution and there you are, straight away, conflating change in one lineage for speciation! Quite dispiriting.

      The rest of your comment is a pretty standard creationist talking point, and therefore confused. Very briefly, the overwhelming majority of mutations have no precipitable effect on their carrier. I’ve written about one mutation I happen to know I carry here , but, in fact, we are all mutants .

      It’s certainly true that some mutations cause diseases, and that disease-causing mutations greatly out number beneficial ones. But that doesn’t mean there aren’t beneficial mutations. There are two two major ways that scientists look for historically beneficial mutations in modern genomes – searching for a pattern of amino-acid changes in proteins that is not expected to happen without selection and searching for regions of chromosomes with decreased diversity as a result of recent selection (i.e. places where background diversity has been removed from the populatoin because a beneficial mutation has quickly become the only gene variant present). We have good evidence that a handfull of our genes have been the result of recent postive selection – one you might want to research is lactase persistence which has evolved independently in Africa and Europe.

      We also have good experimental evidence for beneficial mutations, my favourite example is the GASP (Growth Advantage in Stationary Phase) pehnotype in bacteria. Very briefly, you take singe bacterium, grow up a culture and split it into two vials. When the cells in the first vial are grown in some medium they quickly reach a point at which they have used up all the resources available to them (the so called “stationary phase”) and the number of cells in the container will plateau. This “plateau” is in fact a very dynamic equilibrium, with different genetic lineages arising and taking over the population in the new (nutrient-starved) environment. If you now go back to the other vial of your ‘original’ cells (genetically identical to those that started you first experiment) and grow them side by side with those that have been through a stationary phase the “aged” cells will always out-compete the “naive” one – even when the culture starts 100:1 naive cells.

    • Jon,

      It’s on my (very long…) TODO list, the main problems would be how bushy the tree would be (especially toward the end) and just where to place some fossils (or, how to represent the uncertainties in their placement).

  • @James Arjuna
    Modern evolutionary theory does not predict net positive mutations. This is a partly why evolution is not seen to be progressive. Of course, David’s post is about how the ‘march of progress’ is a artificial construct and not an accurate representation of our branch of the Hominini. If you’d picked up on that, you probably wouldn’t be making those generic comments.

    Our rather sideways evolution is interesting. The human genome, like all mammal genomes, is riddled with viruses and retrotransposons. You might think that insertions of viral DNA would be a bad thing, and some of the time you’d be right. But one of our now-vital placental proteins originates from a virus, co-opted from viral infectivity to mammalian pregnancy.

    Also, transposable elements – self-replicating elements in our genome – are often implicated in disease when they insert new copies of themselves in our genome. However, a key human-only brain development gene, is partly made out of cobbled-together Alu repeats.

  • James

    The assertion that mutations can only be deleterious is an appalling display of ignorance of genetics. Whether such a mutation is deleterious can only make sense if we also know something about the environment the organism lives in. There are a number of blood-cell mutations that are quite beneficial if you live in a malaria-prone environment.

    Second, we could simply put to mutations that involve sequence duplications. For example, the Brown et al. classic 1998 experiment with yeast in low glucose environments, showed that quadruplication of the HXT6/7 genes led to increased fitness in that environment. Similarly, our ability to see in the red-spectrum (as opposed to the usual mammalian colour-blindness) is a consequence of receptor-genes being duplicated and being co-opted & evolve to see red.

    More significantly, if we start looking at these genetic diseases they also map to the primate clade humans are found on. Our pseudogenes- rather than being uniformly and randomly distributed amongst species- are actually clustered in primates. And they converge on to the great-ape clades, and the chimp-human branch.

    The deliberate extension of needless suffering and death to other primates by ‘creating’ them with the same defects as us, renders the belief in a loving, intelligent and merciful creator as abhorrent and absurd.

  • The efforts to enlighten James may provide useful information to other readers — but I imagine those other readers are already scientifically minded, whereas James himself obviously has no interest in facts. Doubt he’s worth the effort.

    On a different topic, the original article says “many of them were contemporaries to each other (as the original diagram makes clear) so can hardly be different steps along a single evolutionary path.” That statement seems to presuppose that, once a species has produced one or more daughter-species, the original species must therefore have ceased to exist. I don’t think that’s correct. One population of a species may give rise to a new species, while another population may not change much at all.

  • Hi Tim,

    Thanks for comment. I spent a lot of time deciding what to do with creationists – treating them as spam may be the best bet (especially as it seems James is a drive by).

    As to your other comment. Species concepts get a bit tricky when you add geological time, but it’s certainly true, as you say, that a population can split with the two daughter species co-existing. My point was you can’t explain that in the “march of progress” mode where one species morphs into another and on to the next.

  • I find it interesting that some of you at least understand the condition of humanity, sort of;
    Here is the summary from accredited sources that anyone can google.
    33% of Americans ages 15 to 64 will die from cancer. This is not attributed to old age, but at ages in the 70’s it gets closer to 1 in 2.
    Since 1975, Childhood invasive cancer rates have risen by 129% in a continuous study from 1975 to 2004 with Childhood Leukemia rising 157%.
    The rate of diabetes in the US is 1 in 12 and is predicted to rise if the current acceleration of genetic defects continues to 1 in 3 by 2050. In other countries the rates are already much higher. Canada has about 34million people and they list 9 million with diabetes.
    1 in 10 people have “rare” genetic diseases and the numbers are also accelerating from mutagens. The average is 1 in 200,000 but the number of different “rare” genetic diseases I very high.
    The number of people with heart disese that need heart surgery is 1 in 15 but it is much higher for the over all heart and circulation diseases. And it is increasing so much so that huge hospital centers, the size of small cities, with over 10,000 employees are planned for the future to centralize an keep costs down. The medical industry is slated to overshadow any other industry that has ever existed on earth, including the computer industry.
    The number of pseudo genes is over 20,000 and the numbers of mutations associated with all these diseases and more, (flat feet, color blindness, knocked knees, and all the normal body defects are way beyond 10,000 found so far by medical research. You can go see all of them at PubMed.com and there are about 460,000 articles on human genetic diseases alone.
    There are zero positive mutations ever found in the human genome. I have had this discussion with thousands of people including many PhD’s of genetics and they cannot show me one totally positive mutation.
    Positive mutation is that it must increase complexity and any of the following: 1/ add new genes with new functions 2/ increase health and fitness to survive 3/ increase intelligence.
    There are none. If you would care to discuss this please goto (google it)
    “Neutral Evolution Forum” and sign up and bring all your evidence.
    Thank You.

    All of this data can be found at; PubMed.com NORD, American Cancer Society and cancer.gov/statistics, American Diabetes Association, CDC, Canadian Diabetes Association,
    and any worldwide statistics on diseases.

  • James,

    This reads a lot like you spamming for your website – I’m happy to answer meaningful questions but anything more like this is likely to end up in the spam folder.

    Very briefly,

    Yes, many diseases are caused by mutations. No one denies most mutations that have any effect on their hosts are harmful. You appear to have missed the bit where you make some conclusion based on this fact.

    “positive mutation” does not mean an “increase in complexity”, and there are plenty of examples of mutations that provide a survival advantage. Lactase persistence (i.e. lactose tolerance) is an obvious example in humans.

  • More factual statistic for you:
    1 in 4 people in the US have STD’s. STD’s are the highest in the 14 to 24 year old and highest in young women in that age group.
    The UK has similar statistics but of the 482,700 people with STD’s 312,000 of them are young (girls to me) women.
    Autism is in pandemic mode with a rise of 120% (+20%) in two years. If you think that 1 in 110 was acceptable is 1 in 88 better?
    1 in 125 babies born with congenital heart disease.
    140% rise in female cancer in the UK since 1975.
    The rise in Breast cancer has been 171% in the same time period.
    The update on childhood invasive cancer is now:
    Since 1975, USA statistics: Childhood invasive cancer rates have risen by 129% in a continuous study from 1975 to 2004 with Childhood Leukemia rising 157%.

    More updated from 2009
    Age 0-14:,1975 11.5 100,000 to 2009 15.5100,000,for an increase of ~35% (135% increase).
    Age 0-19: 1975 13100,000 to 2009 17.3100,000 for an increase of ~34% (134% increase)..

    Once again I have asked all the believers in Evolution to supply even on beneficial mutation that is verifiable.
    I don’t think people understand what that means.
    Verifiable mutation: You have a massive example of a population without the mutation and this new beneficial mutation shows in the same population.

    We have 300,000 papers from medical research that show deleterious mutations associated with diseases, and WE KNOW FOR A FACT THAT THESE MUTATIONS ARE MUTATIONS BECAUSE WE HAVE EXAMPLES OF THE PRIOR FIT CONDITION IN PEOPLE WHO DO NOT HAVE A PARTICULAR DISEASE.

    The numbers are up to 11000 mutations associated with diseases. Zero beneficial mutations not associated with diseases.

    Since all we see in the 36,000 medical papers I have read on mutations and just starting because there are over 300,000 just on “human genetic disease”. It is absolutely clear beyond any faith or belief that there is no documented positive mutation that could add anything or would indicate even the slight possibly of evolution working any other way than a downward direction towards extinction.

    It is clear from the data on our cousins the chimp that their DNA is really messed up with estimated over 160,000 deleterious mutations and they have all the same diseases as humans (or the primate version) at much younger ages and only live to 30 max (not average) in the wild.

    I would say that the fact that they are nearly extinct is a good message for us on the direction we are heading if we don’t come into reality and recognize our serious problem and unify humanity to solve this.

    Faith has nothing to do with science. PERIOD. I don’t have a religion, and I certainly am not going to take this knowledge I have gained and not tell people about it.
    Defending some dogma of faith in your faith religion is not good for humanity. And the idea that your religion negates moral behavior is not good. All beliefs are bad for humans! PERIOD Historically proven over and over.

    It is well known in medical studies that STD’s cause mutations in fetuses. PERIOD. Mutations are never good. We now have all the evidence we need to work towards correcting the problems by stopping our mutagenic behavior. (Our genetic suicide over some politically controlled BS)

    This idea that humans evolved is not science it is in the same classification as voodoo.

    We have all the absolutely irrefutable physical evidence in DNA to make adjustments to this science and correct the “dogma” to fit what is actually seen in real physical evidence.

    But just like the flat earther’s this HEMG will not die until all the believers are gone and stop promoting their faith. By that time (at the present rate of genetic destruction) 50% of people under 64 years will die of cancer (instead of the 33% now) and the rest will not be reproducing very well and babies will be dying in the 10% range from genetic defects.

    Your hate of religion has no value to children suffering from cancer.
    By the way the highest rates of childhood invasive cancer in in the under 1 year old babies.

    It is not magic is is biology and science. These extremely alarming increases in genetically caused diseases should wake you up. But most are so wrapped up in dogma of supporting beliefs that by the time we are way beyond any possibility of health, it will be too late.

    I think all religious BS needs to be removed from science. This Evodelusionism is just another dumb stupid religion based on projection of faith.

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