The increase [in complexity] has been neither universal nor inevitable. Bacteria, for example, are probably no more complex today than their ancestors 2000 million years ago. The most that we can say is that some lineages have become more complex in the course of time. Complexity is hard to define or to measure, but there is surely some sense in which elephants and oak trees are more complex than bacteria, and bacteria than the first replicating molecules.
Image from www.twoheadedquarter.net.
Yesterday, I ran a bit long about Elizabeth Pennisi’s new article in Science, “The momentous transition to multicellular life may not have been so hard after all.” I’m not the only one who noticed it, though; Uncommon Descent also commented (“At Science: Maybe the transition from single cells to multicellular life wasn’t that hard?“). There’s not much to it, just a longish quote from the article followed by this:
So at the basic level, there is a program that adapts single cells to multicellularity? Yes, that certainly makes multicellularity easier and even swifter but it also make traditional Darwinian explanations sound ever more stretched.
So if the evolution of multicellularity is easy, that’s evidence against “traditional Darwinian explanations.” Remember “Heads I win, tails you lose“?
…if multicellularity is really complicated, that’s evidence for intelligent design. But if multicellularity is really simple, that’s evidence for intelligent design.
I spent the last week of June backpacking in Baxter State Park, Maine. When I finally emerged from the woods, my first stop was Shin Pond Village for a pay shower, a non-rehydrated breakfast, and free internet access. Among the week’s worth of unread emails were a nice surprise and a not-so-nice surprise. The not-so-nice surprise was a manuscript rejected without review; the nice surprise was a new article by Elizabeth Pennisi in Science, which came out when I was somewhere between Upper South Branch Pond and Webster Outlet.
Upper South Branch Pond, Baxter State Park, Maine. I spent two nights here.
The article, for which I was interviewed before Baxter, synthesizes recent work across a wide range of organisms that suggests that the evolution of multicellularity may not be as difficult a step as we often assume:
The evolutionary histories of some groups of organisms record repeated transitions from single-celled to multicellular forms, suggesting the hurdles could not have been so high. Genetic comparisons between simple multicellular organisms and their single-celled relatives have revealed that much of the molecular equipment needed for cells to band together and coordinate their activities may have been in place well before multicellularity evolved. And clever experiments have shown that in the test tube, single-celled life can evolve the beginnings of multicellularity in just a few hundred generations—an evolutionary instant.
Back in September, I reported on an arXiv preprint by Pierre Haas, Stephanie Höhn, and colleagues*, “Mechanics and variability of cell sheet folding in the embryonic inversion of Volvox.” A revised version of that manuscript has now been published in PLoS Biology (“The noisy basis of morphogenesis: Mechanisms and mechanics of cell sheet folding inferred from developmental variability”).
Figure 3 from Haas, Höhn, et al. 2018. Inverting Volvox globator embryo visualised by selective plane illumination microscopy of chlorophyll autofluorescence. Top row: maximum-intensity projection of z-stacks. Bottom row: tracing of midsagittal cross-sections; the colour scheme indicates image intensity. Scale bar: 50 μm.
Inversion is a crucial process in the development of algae in the family Volvocaceae (which includes Colemanosphaera, Eudorina, Pandorina, Platydorina, Pleodorina, Volvox, Volvulina, and Yamagishiella), because they start off inside-out, with their flagella pointing inward. Inversion gets the flagella on the outside where they are useful for propulsion.
WordPress has a “publicize” function that automatically sends an email and posts to social media when I publish a new blog post. Unfortunately, the email and social media posts accompanying my last blog post linked to the wrong post (not even one of mine; it’s a decade-old post by PZ Myers). The correct link is https://freethoughtblogs.com/fierceroller/?p=4606.
I’m going to go ahead and guess that the link for this post is wrong, too; it should be https://freethoughtblogs.com/fierceroller/?p=4612. Hopefully Freethought Blogs will get this fixed soon.
I recently argued that asking for letters of reference to be submitted with applications for tenure-track positions devalues the time of highly productive scientists:
Letters of recommendation should be requested by the committee, and they should be requested after the first cut.
A senior researcher who’s a friend and colleague recently told me that for the last few years, she has simply not applied for any position that asked for letters of reference up front. It’s not hard to understand why. After a while, you start to feel that you’re imposing on your references (in reality, it’s the search committees who are imposing). In my case, I’ve submitted well over a hundred such applications, which means that each of my three references has supplied over a hundred letters (and thank you for that).
Starting tomorrow I’ll be on vacation in Maine for two weeks, so posts are likely to be few and far between. The week of June 24, I’ll be completely unreachable, so if you’re a first-time commenter, your comment won’t get approved until around July 1.
Wow, that’s really Maine’s flag. It’s not the worst, but it’s pretty bad.
I should say Tina/Nora/Victoria, since, as Owlmirror pointed out, she signed her second email to me as Victoria. No problem, Tina/Nora/Victoria, I keep forgetting to sign as Paul myself!
When we last heard from Tina/Nora/Victoria, she was concerned about what happened to the payment I had her FedEx to the Federal Trade Commission, and I told her
You would have to ask A. Robinson. I don’t know who that is, maybe a Harkonnen spy. At any rate, I never got the payment.
Tina/Nora/Victoria is happy to take my word for it. Of course, it’s a fake cashier’s check to begin with, so the only thing she’s really out is the cost of a FedEx overnight shipment.
I’ve been sitting on this for a while, not wanting to piss off hiring committees who might evaluate my own applications. I have applied for over a hundred tenure-track faculty positions, and I’ve had over a dozen in-person interviews. One of the things that has always struck me is the incredible degree to which the time of anyone not on the hiring committee is devalued. This is true of the applicants’ time, but today I’m mainly talking about the time of their references.
It’s typical to request three letters of recommendation with an application, but some departments will request four or (rarely) five. In most cases, the application is considered incomplete and will not be considered until all of the letters are submitted. If one of your references has a hard time with deadlines, tough.
In most cases, your references will be fairly senior scientists, Associate Professor or above. It would be nearly impossible, for example, for your Ph.D. advisor to be an Assistant Professor, since that position typically lasts about as long as a Ph.D. In my case, all three of my references were full Professors, one a department head. In nearly every case, all three references will be highly productive scientists. Their time is valuable, not just in terms of salary but in terms of advancing science. Requiring letters of recommendation up front wastes it.
Letters of recommendation should be requested by the committee, and they should be requested after the first cut.
That’s effectively what the president’s lawyers are arguing: President Trump is above the law. Here’s a quote from the letter:
It remains our position that the President’s actions here, by virtue of his position as the chief law enforcement officer, could neither constitutionally nor legally constitute obstruction because that would amount to him obstructing himself, and that he could, if he wished, terminate the inquiry, or even exercise his power to pardon if he so desired.