Problems with major transitions: Maureen O’Malley & Russell Powell respond

The Great Oxidation Event by Adelle Schemm.

The Great Oxidation Event by Adelle Schemm.

In a recent series of posts, I reviewed Maureen O’Malley and Russell Powell’s paper in Biology and Philosophy, “Major Problems in Evolutionary Transitions: How a Metabolic Perspective Can Enrich our Understanding of Macroevolution.” Although they made several good points, I thought that some of their criticisms were off the mark and that their proposed solution to the real and perceived problems with the major transitions framework was unsatisfying.

Drs. O’Malley and Powell are both heavy hitters in the philosophy of biology, and as I usually do when I dig deeply into someone else’s paper, I invited them to respond to my criticisms. They kindly provided a thoughtful rebuttal and permitted me to post it here. I’ll have more to say later, but for now I’ll just say that they make some good points and (most importantly) fairly represent my arguments. As usual for guest posts, I have made no edits to the content of their response, only formatted and added links:

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The evolution of undifferentiated multicellularity: the Gonium genome

Blogging took a backseat to the wedding of two dear friends two weekends ago and to morel hunting last weekend, so I’m only now getting around to a post that should have been written weeks ago (I promised on April 22 that it would be out the following week). Last month, Erik Hanschen and colleagues published the Gonium pectorale genome, filling in some crucial bits of the transition to multicellular life in the volvocine algae. This was a big project, taking several years and involving over 20 authors from over a dozen institutions. The final paper is open access in Nature Communications.

I did post an effort to explain some aspects of the paper to the cdesign proponentsists at Evolution News and Views, who, by their own admission, failed to understand it (“After reading this paper, we’re none the wiser.”). I also complained of the science media’s tendency to refer to all algae as ‘pond scum.’ The lead author of the genome paper kindly followed up with a guest post addressing some of ENV‘s other misunderstandings, such as the purpose of model organisms in biology and the difference between ‘assertion’ and ‘evidence’. But now it’s time to dig into what the genome paper actually says.

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Thoughts on a year of blogging

Facebook reminded me the other day that it’s been a year since I started the original Fierce Roller blog. I didn’t know back then if I’d stick to it this long, and I still don’t know if I’ll keep it up another year. One step at a time.

HelloWorld

My very first blog post.

What is Fierce Roller, exactly? I guess it’s a few different things. One of the ideas from the start was to be a service to the Volvox community, reporting new papers, meetings, and news relating to volvocine algae. But that has only been one aspect. It is also a place for me to talk about my research interests, both scientific and philosophical. Scientific usually means that it has to do with the so-called ‘major transitions’ or related evolutionary themes. I wish I could cover this topic more thoroughly, but it has become a big subfield within evolutionary biology, and I can’t possibly keep up with the relative flood of papers. Philosophical usually means that it has to do with the one discussion in the philosophy of science that I’ve contributed to, about the meaning of biological individuality. There is also, of course, a thread of skepticism, occasionally about ‘alternative’ medicine, but usually responding to creationist arguments.

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Time for a revision? Maureen O’Malley and Russell Powell on Major Transitions, part 3

Maureen O’Malley and Russell Powell say that the major transitions framework is in need of repair. They have a point, or rather several good points. I have looked at their criticisms of three different versions (the original framework as laid out in the book by John Maynard Smith and Eörs Szathmáry, Rick Michod’s ‘evolutionary transitions in individuality‘ framework, and Szathmáry’s revised ‘Major Transitions 2.0‘). But what is their proposed fix, and will it have the intended effect?

Figure 4 from O'Malley and Powell 2016. Two major aeons of evolution (modified from Falkowski 2006). ‘Gya’ stands for ‘billion years ago’; the date for the origin of photosynthesis may need to be pushed back (see Crowe et al. 2013).

Figure 4 from O’Malley and Powell 2016. Two major aeons of evolution (modified from Falkowski 2006). ‘Gya’ stands for ‘billion years ago’; the date for the origin of photosynthesis may need to be pushed back (see Crowe et al. 2013).

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Heads I win; tails you lose: Evolution News & Views on Gonium, part 1

Figure 6 from Hanschen et al. 2016. Multicellularity hinges on the evolution of cell cycle regulation in a multicellular context with subsequent evolution of cellular differentiation (here, cell size-based) and increased body size.

Figure 6 from Hanschen et al. 2016. Multicellularity hinges on the evolution of cell cycle regulation in a multicellular context with subsequent evolution of cellular differentiation (here, cell size-based) and increased body size.

Remember how I said they’re prolific? Before I’ve even had a chance to write up my thoughts on the Gonium genome paper, Evolution News & Views has already published theirs. The story has also been picked up by the Washington Post, New Historian, GenNews, and ScienceDaily (that last one looks like just a reprint of the press release from University of the Witwatersrand). By the way, the genome paper is open access, so you don’t need a subscription to see it for yourself.

We already know that cdesign proponentsists are not fans of research into the evolution of multicellularity, and that they have trouble understanding it. In an unsigned article on the Gonium genome at ENV, they admit that

After reading this paper, we’re none the wiser.

That’s too bad. I’m here to help.

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Time for a revision? Maureen O’Malley and Russell Powell on Major Transitions, part 2

One of the cool things about studying the so-called major transitions is that they are as interesting to philosophers of science as to biologists. So you really can’t help being exposed to the philosophy of science literature, and many (maybe most) biologists in the field cross the lines at least occasionally. I’ve been to both, and I’m here to tell you that philosophy conferences are more fun than biology conferences.

Last time, I briefly summarized the various forms of the major transitions framework and addressed one of O’Malley and Powell‘s criticisms, that the framework is progressivist. Now I’d like to look at their other two problems: lack of unity and missing events. By and large, I agree with these points, although there are some caveats I’d like to point out. Next time, I’ll consider their proposed solution, which I’m afraid I don’t find helpful.

Disunity is actually O’Malley and Powell’s first criticism, but it will be a bit more complicated than progressivism to address, and I was short on time on part 1. Essentially, they are arguing that the major transitions are not a natural kind, philosophese for groupings that belong together because of some fundamental commonality, as opposed to more arbitrary groupings whose members are only superficially similar. So what are the transitions? Here’s the list from the book:

Table 1.2 from Maynard Smith J, Szathmáry E (1995) The Major Transitions in Evolution. Oxford University Press, Oxford.

Table 1.2 from Maynard Smith J, Szathmáry E (1995) The Major Transitions in Evolution. Oxford University Press, Oxford.

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Time for a revision? Maureen O’Malley and Russell Powell on Major Transitions, part 1

The so-called ‘Major Transitions’ framework is an attempt to explain the hierarchical structure of life on Earth: genes within chromosomes, chromosomes within cells, cells within cells (eukaryotic cells), individuals within sexual partnerships, cells within multicellular organisms, and organisms within societies. The best-known attempt to unify the origins of these relationships is a book by John Maynard Smith* and Eörs Szathmáry, The Major Transitions in Evolution.

MajorTransitionsCover

First published in 1995, the book focused on the origins of these hierarchical levels, connecting them with the unifying theme that

…entities that were capable of independent replication before the transition can replicate only as part of a larger whole after it.

For example, after a transition from unicellular to multicellular organisms (there were several), cellular reproduction either contributes to the growth of the organism or to production of new multicellular organisms.

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Hello world!

Hi, everyone! I’m excited (and surprised, to be honest) to join the freethoughtblogs community. I’ve been blogging for about ten months over at fierceroller.com, a platform that I initially set up to serve the (pretty small) Volvox community. Volvox, in case you haven’t encountered it before, is a multicellular green alga, just visible to the naked eye, that is an important model system for understanding the evolution of multicellularity. Volvox is Latin for ‘fierce roller,’ a name bestowed by Linnaeus, who was impressed by their ability to move around without limbs.
Volvox aureus. Beautiful, isn't it?

Volvox aureus. Beautiful, isn’t it?

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Volvox 2015: me and my horsy and a quart of beer

 

Licensed to Ill

When I was a senior in high school, I gave my friend Arthur Malpere a ride to school in my ’77 MGB just about every day (well, every day it was running). I had a cassette of the then fairly new Licensed to Ill, and Art insisted that we listen to it every damn day. The ride to school was on the order of ten minutes, so we would listen to ten minutes on the way to school, then pick up where we left off, usually mid-song, on the way home (for those of you too young to remember cassettes, it wasn’t trivial to return to the beginning of a song). Of all the outstanding songs on that album, possibly my favorite was “Paul Revere,” a sort of old-west style automythology of the band’s origin (in spite of the casual misogyny, I still do like it pretty well).

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AbSciCon day 1

Jennifer Pentz, Dinah Davison, and Cristian Solari enjoying a glass of wine.

Jennifer Pentz, Dinah Davison, and Cristian Solari enjoying a glass of wine.

I’m in Chicago for the biennial Astrobiology Science Conference (AbSciCon). This is always (well, it’s my second time) a fun one, with topics ranging from origins of life to proposed interplanetary missions. I took the train from Whitefish, Montana, which is a bit of an adventure in itself.

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