Species and systematics
evolvingthoughts | May 19, 2009In addition to the "missing link" trope that is being dished out about the new primate fossil, is another one, more subtle and insidious: it's the ancestor of all primates. How do they know that? Consider a biologically realistic scenario: at the time there were probably hundreds of species of small bodied mammals with tails and feet like that. One of these species may be the ancestor of all primates, but what are the odds that a specimen from that species is the one that was preserved? Just as all primates now look remarkably similar overall, but one may be the common ancestor of a group in…
evolvingthoughts | May 18, 2009One of the problems that many people have with evolution is not religious, but philosophical. If evolution is true, they think, then we are at sea - nothing is fixed, nothing is determinate, all coherence is gone, as Donne famously lamented of the death of the two-sphere universe and physics. This is, I believe, a valid worry. But it is not new or due to evolution: Heraclitus worried about it, as did Parmenides, and the solutions given by Plato and Aristotle against the atomists were in effect ways to deny that what really counted was changing. They called change "degeneration" or "corruption…
evolvingthoughts | May 18, 2009The wonderful Project Gutenberg has just released a fully HTMLised version of R. C. Punnett's (he of the famous "square") 1911 book Mendelism, which shows how quickly the implications of Mendelian genetics, rediscovered 11 years earlier, were worked through. It's a wonderful read, and anyone with a slight knowledge of biology and the interest to work through the examples can understand it, something one cannot say of texts on science for very much longer after this. I was particularly interested in the following passage, from page 150:
One last question with regard to evolution. How far does…
evolvingthoughts | May 16, 2009Chris Nedin has another post of great interest (even if it is for a late period, the Pleistocene) which goes into my file of "the older naturalists were great observers", as he shows how modern chemistry supports Richard Owens' diagnosis of Thylacoleo as a carnivore, even though it is in a clade of herbivores.
evolvingthoughts | May 11, 2009Again, the press are talking about "the missing link". Let's get one thing clear. There is no missing link. Rather, there are an indefinite number of missing branches. To have a missing link, you need to visualise evolution as a chain. If there's a gap in the chain, then you have a missing link. But evolution, at least at the scale of animals and plants, is mostly a tree. And all we see are individual nodes of the tree, the extant species that form, in Darwin's metaphor, the leaves of the living tree, and the extinct species that form branching points deeper in the tree. But we do not have…
evolvingthoughts | May 10, 2009Before this text in 1686, the term species just meant some sort or kind of organism. It was a Latin word in ordinary use without much meaning in natural history, but then arguments began whether or not there were one or more species for this or that group, and so it became important to know what was meant by the term in natural history. That is, a distinctly biological concept of species was needed, and John Ray gave it here:
The translation is this:
In order that an inventory of plants may be begun and a classification (divisio) of them correctly established, we must try to discover…
evolvingthoughts | May 8, 2009As the science of order ("taxonomy"), Systematics is a pure science of relations, unconcerned with time, space, or cause. Unconcerned with time: systematics is non-historic and essentially static; it knows only a simple juxtaposition of different conditions of form. Unconcerned with space: geographical factors are not primary criteria in the definition of taxonomic units. Unconcerned with cause: systematics has no explanatory function as far as the origin of the system is concerned; it is merely comparing, determining, and classifying.
Borgmeier, Thomas. 1957. Basic Questions of Systematics.…
evolvingthoughts | May 8, 2009It's called Philosophy and Theory in Biology. This is based on some heavy hitters: Massimo Pigliucci, Jon Kaplan, Alan Love and Joan Roughgarden are the editors, and the editorial board looks like a Who's Who of philosophy of biology. No apparent page charges, and it's online only (I hope they take care of the enduring archiving), but it looks interesting. How it differs, apart from being virtualised, from Biology and Philosophy, Biological Theory and the several other more specialised journals I can't yet say.
evolvingthoughts | May 6, 2009My union is calling a strike next Tuesday. I'm not sure what to do. I don't teach, and have no administrative duties, so should I stop thinking from for 8 hours? I'm not sure the administration would notice...
Rob Skipper at hpb etc. has a series of podcasts from the series of lectures on Darwiniana that were held there recently. They include John Beatty, Roberta Millstein and Ken Waters, all serious folk in philosophy of biology (although Roberta, at least, is not serious all the time). From the sublime to the faintly absurd, you can also see my talk in Lisbon, one of them, anyway, at…
evolvingthoughts | May 1, 2009It is often stated in the literature that Linnaeus late in life turned to an evolutionary view based on hybridisation (e.g., Clausen, Keck and Hiesey 1939). I myself have repeated this, but as always it's worth looking at the actual text. Unfortunately I have so little Latin that I can't even use pig Latin, so it is great to find, yet again, that archive.org has it in an English edition published in 1783. I love archive.org. Deeply.
It's in the context of what he bases his system on, the "fructification" of the plants; i.e., the reproductive organs:
26. The PRINCIPLE of Fructification, the…
evolvingthoughts | May 1, 2009... says Linnaeus:
False BOTANISTS proclaim the Laws of the Art before they have learned them:
Extol absurd Authors, and are jealous of the excellent ones:
Steal from others, producing nothing of their own:
Boast much of a little knowledge:
Pretend they have discovered a natural Method:
Assert the Genera to be arbitrary. [System Vegetabilis 1774, §27]
I wonder who he is talking about.
evolvingthoughts | April 29, 2009As I investigate the use of tree diagrams in the nineteenth century, I keep running across things that shouldn't be there. One of them was this book:
Herdman, William Abbott. 1885. A Phylogenetic Classification of Animals (For the Use of Students). London; Liverpool: Macmillan & Co.; Adam Holden.
It's on Archive.org, but they didn't properly scan the figure on the foldout (a real problem of the electronic versions of old books is that they don't scan the foldout figures. Imagine the Origin without the one figure). So I bought a copy. It's a real revelation - he correctly uses "…
evolvingthoughts | April 23, 2009"Few topics have engaged biologists and philosophers more than the concept of species, and arguably no idea is more important for evolutionary science. John S. Wilkins' book combines meticulous historical and philosophical analysis and thus provides new insights on the development of this most enduring of subjects."—Joel Cracraft, American Museum of Natural History
"This is not the potted history that one usually finds in texts and review articles. It is a fresh look at the history of a field central to biology, but one whose centrality has changed in scope over the centuries. Wilkins' book…
evolvingthoughts | April 17, 2009Pam Ayers once noted that in car and hedgehog fights, the hedgehog comes off worse, but what about in python and human fights? It seems they reached a standoff in Kenya recently. He bit the snake on the tail while it tried to eat him. He held off by using a shirt to blog its mouth, and a mobile phone to call for help. It managed to take him into the trees, which is unheard of, Disney animated movies notwithstanding.
evolvingthoughts | April 9, 2009Older histories of biology are often full of useful and interesting facts. One of my all-time favourites is Eric Nordenskiöld's history, but I came across an earlier one by Louis Compton Miall in which I found this text:
Bonnet in 1745 traced the scale of nature in fuller detail than had been attempted before. He made Hydra a link between plants and animals, the snails and slugs a link between mollusca and serpents, flying fishes a link between ordinary fishes and land vertebrates, the ostrich, bat, and flying fox links between birds and mammals. Man, endowed with reason, occupies the highest…
evolvingthoughts | April 2, 2009Well yes it was a joke. But it was based on the inappropriate manner in which the well-known work on lateral transfer was reported by New Scientist as showing that Darwin was wrong. That genes occasionally cross over taxonomic borders among single celled organisms by transduction (viral exchange), conjugation (sharing plasmid DNA) and transformation (reuptake of naked DNA in a medium) has been known for a while. What this showed was that gene trees and taxa trees don't exactly coincide. But for the animals and plants Darwin mentioned, evolution still runs in trees.
The other thing I was…
evolvingthoughts | March 31, 2009A new study into the transfer of genetic material laterally, or across taxonomic divisions, has shown that evolution does not proceed as Darwin thought, and that in fact the present theory of evolution is entirely false. Instead, it transpires that lateral genetic transfer makes new species much more like Empedocles' "random monster" theory over 2000 years ago had predicted.
Publishing in the Journal of Evolutionary Diversions, the major journal in the field, Professor Augustus P. Rillful and his colleagues of the paragenetics laboratory at the University of Münchhausen in Germany have shown…
evolvingthoughts | March 26, 2009It's true! Dinosaurs still exist. John Conway dissected a Rhamphorhyncus, and drew what he saw, here.
I had "dinosaur" in the title but as Chris points out, that's a bad error, like calling a mammal a turtle.
Damn, I'm not having much luck. Not a pteranodon then...
evolvingthoughts | March 24, 2009Anthony Grayling, who does a really interesting review column in the Barnes and Noble Review, entitled "A Thinking Read", has a piece on Jerry Coyne's book Why Evolution is True. This saves me having to read it and review it for you myself.
The column title is a pun on Blaise Pascal's statement that "Man is but a reed, the most feeble thing in nature, but he is a thinking reed". A pun which I wish I had come up with.