Pleodorina inversion

Stephanie Höhn and Armin Hallmann have published a detailed study of the developmental process of inversion in Pleodorina californica. Pleodorina is one of the two genera we usually refer to as ‘partially differentiated’ (the other is Astrephomene), meaning that some of their cells are specialized for motility and never reproduce (soma) and some perform both motility and reproductive functions. P. californica is pretty big, up to about 1/3 of a millimeter, easily visible to the naked eye (though you’d need better vision than mine to make out any details).

Stephanie Höhn sampling a pond near Cambridge University during the Volvox 2015 meeting.

Stephanie Höhn sampling a pond near Cambridge University during the Volvox 2015 meeting.

Like all members of the family Volvocaceae, P. californica undergoes complete inversion during development:

After the completion of the cell division phase and before inversion, the embryos of Gonium, Pandorina, Eudorina and Pleodorina consist of a bowl-shaped cell sheet, whereas the embryonic cells of Volvox form a spherical cell sheet. With exception of the genus Astrephomene, all multicellular volvocine embryos face the same “problem”: the flagellar ends of all the cells point toward the interior of the bowl-shaped or spherical cell sheet rather than to the exterior, where they need to be later to function during locomotion. [References removed]

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Volvox 2017 – save the date

The Fourth International Volvox Conference will be held in St. Louis, Missouri August 16-19, 2017, with Jim Umen organizing.

Starting in 2011, we have had a Volvox meeting every other year (every year there’s not a Chlamydomonas meeting, that is). The first meeting was at Biosphere 2 outside of Tucson, Arizona, the second at the University of New Brunswick, and the third at Cambridge University.

Biosphere 2

Biosphere 2, the site of the First International Volvox Meeting in 2011.

You don’t have to study Volvox to join us; the meeting is open to anyone with an interest in the evolution of multicellularity (last year’s invited speaker was Professor Pauline Schapp, who studies cellular slime molds).

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Volvox live wallpaper for Android

Anybody remember iGoogle? Kind of a customizable home page for your web browser. I used it until they shut it down, and I even spent a few hours designing a Volvox iGoogle theme (when I should have been writing my thesis):

igoogle

I think three or four people used it; Google would only tell me “less than 100.” Nevertheless, if you feel the need for some Volvox in your life but you don’t have a handy supply of AF-6 medium, lighted incubator, and dissecting scope, there’s still a way:

We have a good news for all VOLVOX fans. You can grow VOLVOX on your smartphone!

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What kind of individual do you mean?

One of the discussions I find most interesting in the philosophy of science is about what exactly constitutes a biological individual (or organism). The discussion would be a lot less interesting if everything were a vertebrate. Vertebrates (nearly always) develop from a single fertilized egg, so the (mostly) genetically homogeneous and (usually) genetically unique unit is the same as the spatially bounded, contiguous and physiologically integrated unit (this doesn’t even cover all the proposed criteria; see Clarke 2010 for a fairly comprehensive list with citations). But when we look outside of the vertebrates, what we often find is that some biological units have some of these properties and either groups or parts of those units have others.

Aphid on dandelion by Amoceann. Public domain image from Wikimedia Commons.

Aphid on dandelion by Amoceann. Public domain image from Wikimedia Commons.

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Coenobium wine

Between the unpacking and the travel, I haven’t had much chance to explore Atlanta, but one of my favorite places so far is Krog Street Market, an indoor market with some really excellent food and beer. I was surprised while browsing Hop City to see this among the Italian wines:

Coenobium wine, purchased at Krog Street Market.

Coenobium wine, purchased at Krog Street Market.

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Andrew Weil advocates cupping

UACIM

Andrew Weil is working to cheapen my degree, and yours if you’re a Wildcat. The director of the Arizona Center for Integrative Medicine, Dr. Weil mixes good medical advice, most of which boils down to “eat better and get more exercise,” with rank bullshit. He advocates (among other nonsense) homeopathy, Ayurveda, and osteopathic manipulations for ear infections.  I’ve been on his mailing list ever since curiosity drove me to take his Vitamin Evaluation (which indicated that I need $147/month worth of supplements).  Honestly, most of it’s pretty unobjectionable: foods you should eat more of, healthy recipes, exercise advice…stuff like that. But, as I’ve said before:

I know Dr. Weil gives a lot of good advice. He also advises a lot of nonsense. A doctor who advises his patients to get their chakras aligned is a quack. A doctor who advises his patients to eat a healthy diet, get more exercise, quit smoking, and get their chakras aligned is still a quack.

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Volvox the art gallery

Volvox Art Gallery. Image from http://www.volvox-stnk.net/.Volvox Art Gallery. Image from www.volvox-stnk.net/.

If you’ve ever seen Volvox alive under a microscope, you probably remember it. They are beautiful, huge (relative to most things in a drop of pond water), and seemingly purposeful as they roll across the field of view. Volvox and its relatives have also played important roles in some big scientific and philosophical discussions, such as the evolution of multicellularity, the evolution of cooperation, and the nature of biological individuality. Given all that, it’s probably not too surprising that the volvocine algae, and Volvox in particular, have inspired a lot of art, including paintings,

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Proxima b is a challenge to materialism, according to David Klinghoffer

David Klinghoffer, a Senior Fellow at the Discovery Institute, thinks the discovery of a relatively close, relatively Earth-like planet presents a challenge not only to evolutionary theory (Klinghoffer thinks every new discovery presents a challenge to evolutionary theory), but to any materialist worldview (“Put Up or Shut Up for Evolution? Nearest ‘Habitable’ Planet Found Orbiting Proxima Centauri“):

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Multicellularity rundown

Too many papers, not enough time: each of these deserves a deep dive, but my list just keeps getting longer, so I’m going to have to settle for a quick survey instead. To give you an idea of what I’m up against, these papers were all published (or posted to bioRxiv) in July and August, 2016. By the time I could possibly write full-length posts about them all, there would probably be ten more!

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