J. S. Huxley part 2: Volvox

Last time, I wrote about Julian Huxley’s 1912 book, The Individual in the Animal Kingdom, and his use of the volvocine algae as an example. I liked most of what he had to say, though I took issue with his assertion that

…all the other members of the family except Volvox…are colonies and nothing more—their members have united together because of certain benefits resulting from mere aggregation, but are not in any way interdependent, so that the wholes are scarcely more than the sum of their parts.

This is, of course, a matter of how we define a multicellular organism, but I think any definition that excludes, for example, Eudorina, is not a very useful one.

This time, I’ll look at the rest of what Huxley had to say about the volvocine algae, most of which is about Volvox:

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J. S. Huxley part 1: Gonium

Julian Huxley was one of the biologists responsible for the merging of Mendelian genetics and Darwinian evolution in the early 20th century, the modern synthesis. His most influential work was Evolution: The Modern Synthesis, published in 1942. Thirty years earlier, though, he published a book on biological individuality, The Individual in the Animal Kingdom. Thankfully, the copyright on this book has expired, so it is now part of the public domain, and a scanned version is available for free in pdf and epub versions from Google.

Huxley Cover

Any book with Volvox on the cover can’t be all bad!

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The Volvox 2017 website is live

volvoxwebheader_3_orig

The website for the Volvox 2017 conference is up at www.volvox2017.org. Registration isn’t open yet, but there’s some information about the venue, the Donald Danforth Plant Science Center in St. Louis. The meeting is set for August 16-19, 2017.

The goal of the International Volvox Conference is to bring together international scientists working with Volvox and its relatives (aka Volvocales or volvocine algae). We cordially invite experimentalists and theorists interested in these fascinating organisms.

I’ll keep you posted!

Evolution of microRNAs in the volvocine algae

The following guest post was kindly provided by Dr. Kimberly Chen. I have edited only for formatting.

MicroRNAs (miRNAs) are a class of non-coding small RNAs that regulate numerous developmental processes in plants and animals and are generally associated with the evolution of multicellularity and cellular differentiation. They are processed from long hairpin precursors to mature forms and subsequently loaded into a multi-protein complex, of which the Argonaute (AGO) family protein is the core component. The small RNAs then guide the protein complex to recognize complementary mRNA transcripts and conduct post-transcriptional gene silencing.

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Origins of the sexes: isogamy and anisogamy

Sex didn’t always involve males and females. I know it still isn’t always between males and females, but that’s not what I mean. I mean that there was a time when sex was happening, but there were no males and females. Sex existed before males and females, and many species are still doing it without them.

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What is a (Volvox) species?

Hisayoshi Nozaki and colleagues have just described some Volvox samples from two lakes and a pond in Japan.

Figure 1A from Nozaki et al. 2016. Volvox sp. Sagami asexual spheroid with daughter colonies (d).

Figure 1A from Nozaki et al. 2016. Volvox sp. Sagami asexual spheroid with daughter colonies (d).

The newly collected strains have a lot in common with another recently described species, Volvox ferrisii, but there are some important differences as well:

…it could be clearly distinguished from all previously described monoecious species of Volvox sect. Volvox by its small number of eggs or zygotes (5–25) in sexual spheroids, with short acute spines (up to 3 μm long) on the zygote walls and elongated anterior somatic cells in asexual spheroids.

In spite of these differences, Nozaki and colleagues stop short of calling the newly collected strains a new species. Why?

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It’s not evolution, just adaptation

…”evolve” is not the correct term. The microbes adapted. – Cornelius Hunter

We heard several accusations during the recent Presidential campaign that one or the other candidate, or an interviewer, had taken a quote out of context. Of course, every quote is taken out of context. That’s what a quote is; otherwise it’s just the whole speech, or interview, or whatever. The important question is whether or not it’s taken out of context in a way that changes its meaning.

One thing I don’t do, and never have done, on this blog is intentionally misrepresent other people’s positions.  The quote above, from a recent post by Cornelius Hunter on Evolution News and Views, means just what it says. He really is arguing that microbial adaptation observed in Lenski-style experiments is not evolution.

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