Following Fierce Roller

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There doesn’t seem to be an RSS button here at Freethought Blogs, but if you use Feedly or some other feed reader (Jema), you can subscribe to fierce roller at http://freethoughtblogs.com/fierceroller/?feed=rss2. I haven’t yet figured out how to subscribe by email, but if that’s your preference there is a slightly kludgy solution: you could convert the rss feed into emails using a service like feedmyinbox or rssfwd.

Tranquil Roller

Volvox by Aeravi. Oil on canvas.

“Tranquil Roller” by Aeravi. Acrylic on canvas.

I have featured Aeravi’s painting and photography previously, and here’s another example.

If you have Volvox– or volvocine-themed art you’d like to see on Fierce Roller, feel free to send it to me.

EDIT: Aeravi does commissions, so if there’s a painting you’d like her to create, get in touch via her website.

Pleodorina starrii

32- and 64-celled colonies of Pleodorina starrii.

32- and 64-celled colonies of Pleodorina starrii. Not to scale. Creative Commons License
Pleodorina starrii by Matthew Herron is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

I spent a year in graduate school trying to cross male and female strains of the volvocine green alga Pleodorina californicaA year. I did some other stuff in that time, but I spent an awful lot of it trying to convince these algae to get busy. I threw everything I could think of at them: four different mating media, different temperatures, different lighting conditions…nothing worked. I never recovered a single viable zygote. I needed to cross them to generate some genetic variation for an ambitious artificial selection study, my ‘official’ dissertation project. Eventually, my advisor suggested I ask Hisayoshi Nozaki for advice.

There is little doubt that Dr. Nozaki is the world’s leading expert on volvocine biodiversity, having described about half of the known species (see for example New Volvox SpeciesVolvox ovalis, and African Volvox in Montana). He responded that the strains of Pleodorina californica I had been failing to breed had been collected many years ago and had probably lost the ability to reproduce sexually (a problem I mentioned in Why don’t we revise volvocine taxonomy?). I had been spinning my wheels, never realizing that I had no hope of success. I should have contacted Dr. Nozaki about eleven months earlier.

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Paywalls revisited

Say you think I’m full of it. Or Larry Moran is. Or ScienceNews, or Scientific American, or PhysOrg. One of us has written about a peer-reviewed paper, and you think maybe we’ve misrepresented it, or cherry-picked the bits we like, or you just want to read a more complete story. There’s good reason to be skeptical: news organizations (and bloggers) misunderstand, misrepresent, or exaggerate scientific studies all the time. But the article is behind a paywall, and you don’t want to have to shell out serious money every time you have your doubts. So you just have to take our word for it, right? Not usually.

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Bacterial flagellum? Never heard of it.

When I wrote about Michael Behe’s shock that any sane person would associate the bacterial flagellum with intelligent design (Michael Behe’s “Secret Obsessions“), I failed to notice something that was staring me right in the face. The masthead for intelligent design blog Uncommon Descent:

UncommonDescentMasthead

Remember, if you meet someone who thinks intelligent design advocates

…think they [bacterial flagella] are examples of “intelligent design”

or that bacterial flagella have

…been at the center of the thinly veiled creationism movement called intelligent design,

you should

back away slowly, smiling, wishing him a nice day…

Volvox by Aeravi

Volvox by Aeravi. Oil on canvas.

Volvox by Aeravi. Acrylic on canvas.

A painting of my favorite critter by my favorite artist. Here’s what she has to say about it:

I am convinced of a connection between arts education and scientific discovery. Also, I love science. Also, science gives artists endless material to play with AND understanding of how things like light work, giving us more tools to play with. Here are some of my paintings inspired by Volvox, a very beautiful algae that lives in freshwater… like Flathead Lake and the Ninepipes Resevoir.

There is lots more good stuff over at her blog…check it out!

Michael Behe’s “secret obsessions”

In his latest post at Evolution News and Views, Michael Behe calls the authors of posts at New Scientist and Genetic Engineering & Biotechnology News ‘crazy’ and ‘clueless’ for associating arguments about the bacterial flagellum with intelligent design (“New Paper on Flagellum Reveals Secret Obsessions“):

Suppose in the course of a pleasant conversation with a colleague you mentioned your vacation last year in Las Vegas. All of a sudden he starts ranting about Area 51 — Vegas is only a few hours away, right? Did you see any lights in the sky? Any military vehicles heading north? You should stay at the Little A’Le’Inn motel like he has six times. You’ll see some funny stuff there.

You’d probably back away slowly, smiling, wishing him a nice day…

[much later] …One crazy person is a coincidence. Two are a trend…What’s more, if you go by what they write, these folks are utterly clueless about what modern ID proponents actually argue. [my emphasis]

The evidence that these authors are crazy and clueless? The New Scientist‘s assertion that the bacterial flagellum is

Loved by creationists, who falsely think they are examples of “intelligent design”

and that of Genetic Engineering & Biotechnology News that

[T]he bacterial flagellum has been at the center of the thinly veiled creationism movement called intelligent design. Subscribers to this belief system have erroneously postulated that the flagellar motor system is “irreducibly complex” and could not have come about through Darwinian evolutionary mechanisms….It is doubtful these findings will sway the opinion of its detractors, yet they do make it extremely more difficult for them to make their case.

Seriously, that is the sum total of the evidence that these authors are ‘crazy’ and ‘clueless’ on the order of UFO true believers. A bit hyperbolic, I think. But where did these clueless authors get their crazy idea to associate the bacterial flagellum with intelligent design?

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Origins of the sexes: Takashi Hamaji on mating type determination

The evolution of sex is one of the big outstanding problems in evolutionary biology. The origin of sex is one of Maynard Smith and Szathmáry’s “Major Transitions,” on which I’m currently teaching a course here at the University of Montana. Our discussion of sex luckily coincided with the visit of the grad-invited Distinguished Speaker, Sally Otto, an important theorist on this topic (among others). Dr. Otto generously agreed to join us for the discussion, which turned out to be one of the best we’ve had.

A related problem to the origin of sex is the origin of males and females. Sexual reproduction doesn’t always involve males and females: lots of species that don’t even have males and females have sex. There are lots of traits that we associate with males and females — fancy plumage, differences in body size and type of genitalia, presence and absence of exaggerated weapons — but what actually defines males and females is differences in gamete size. Animals, plants, and other organisms with males and females are oogamous: males have small, swimming sperm, and females have large, immotile eggs. But lots of single-celled eukaryotes have only one size of gamete. We call these isogamous (‘equal gametes’).

Some volvocine algae are isogamous (such as Chlamydomonas), some are oogamous (such as Volvox), and some (such as Pleodorina) are anisogamous (‘unequal gametes’), meaning that the gametes come in two sizes but both can swim. In spite of not having sexes per seChlamydomonas, like a lot of isogamous organisms, comes in two ‘mating types’, which are arbitrarily called ‘plus’ and ‘minus.’ The mating types are self-incompatible, in other words plus can only mate with minus and vice versa.

All this variation in mating systems makes the volvocine algae a great model system for understanding the evolution of sex and the sexes (see ‘Volvox 2015: all about sex‘). We know from previous work that males evolved from the minus mating type and females from the plus in this lineage. But males and females have evolved from isogamous ancestors many times, and to my knowledge we don’t know which came from which for any other group.

Takashi Hamaji and colleagues have just published an analysis of the genomic region that determines mating type in Gonium pectorale, an isogamous alga more closely related to Volvox than to Chlamydomonas.

Figure 1 from Hamaji et al 2016. A schematic diagram for phylogenetic relationships of selected volvocine species based on Nozaki et al. (2000); Herron and Michod (2008). The top row illustrates gamete type and structure. Tubular mating structures in isogamous gametes are indicated with red bars at the flagellar base. The possession of a MID gene is shown next to the minus mating type or male gametes. The lower row of cartoons depicts vegetative morphology (not to scale) for the indicated species.

Figure 1 from Hamaji et al 2016. A schematic diagram for phylogenetic relationships of selected volvocine species based on Nozaki et al. (2000); Herron and Michod (2008). The top row illustrates gamete type and structure. Tubular mating structures in isogamous gametes are indicated with red bars at the flagellar base. The possession of a MID gene is shown next to the minus mating type or male gametes. The lower row of cartoons depicts vegetative morphology (not to scale) for the indicated species.

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