I am going to take advantage of figures I prepared for a talk I gave recently, where I had to explain a diagnostic characteristic of ants during the introduction. As I have mentioned before, ants are peculiar among wasps and bees in that their mouthparts are directed forward, rather than downward, in a condition known as prognathy (pro-, anterior, projecting; -gnathus, jaw).
Forget the Friday winter break parties at the workplace, I’m stuck at home preparing slides for a short talk I’ll be giving on Monday. I’m not complaining though. This is the Portuguese meeting on evolutionary biology I mentioned earlier. The odd date (the 21st of December for the past four years) is to accommodate all the nationals pursuing Ph.D.s and postdocs abroad that come home during the holidays.
The meeting is organized by young researches, and this year will be specially interesting because there will be a discussion about creating a national society of evolutionary biologists.
I will be talking about the evolution of mouthparts within ants, covering some fascinating new discoveries that I haven’t share here yet but will blog about some time in the near future. In the mean time, here are a couple of my slides.
Here is a hidden treasure in the web.
Robert E. Snodgrass was an American entomologist who published extensively on arthropod anatomy and evolution during the first half of the twentieth century. He was as knowledgeable about arthropod morphology as he was a superb artist– you can see some of his illustrations decorating the banner of this blog. His name is synonymous with insect morphology: his 1935 textbook on the subject (reedited by Cornell University Press in 1993) is still the main reference for any modern course in entomology.
Snodgrass was a lecturer in the University of Maryland for most of his academic life. In 1960, two years before his death, he gave a series of three lectures that were recorded in audio tape. Fortunately for us Jeffrey W. Shultz, professor of entomology at Maryland, has digitized and made these lectures available through a nicely designed page called The Snodgrass Tapes. › Continue reading
Up until resuming posting a couple of weeks ago you may had thought I was dead. Well, fear not (nor rejoice just yet). I am now happy to report that those previous months of blogging slowness paid off: I got funding for the project I wrote during the summer.
Starting next year I will be working as a postdoc in the laboratory of Patrícia Beldade at the Instituto Gulbenkian de Ciência in Portugal. This is an evolutionary developmental biology lab, an area of research fondly know as EvoDevo.
EvoDevo ask questions that are of a different nature than the classical Neo-Darwinian ones. For example, in the latter you always presuppose that variation exists in populations and that there is a link between what you see at the level of an organism’s morphology (its phenotype) and the underlying genetics (its genotype), and you study how natural selection then goes to mess things around. In EvoDevo you don’t give these things for granted. Rather, you ask how do new features (novelties and innovations) arise in the first place and exactly how does the link between genotype and phenotype comes about through the developmental process. From there, what you seek is to understand evolution as a process of modification of development.
Familiar to many, you can know how old a tree is and how fast it has grown by counting the number of rings in a cross section. Well, you can do the same with the long bones of vertebrates.
Now Gregory M. Erickson and co-workers published a paper in which they did just that to a specimen of one of the most famous fossil forms around: Archaeopterix. Watch Mark Norell, paleontologist from the American Museum of Natural History and co-author of the paper, explain the results:
The Department of Entomology at Cornell University saw a time of great research and teaching in insect morphology at the end of the Twentieth Century, most of which came from the efforts by two extraordinary systematists: William L. Brown Jr. and George Campbell Eickwort.
The lateral eyes of adult insects (and most Arthropods) known as compound eyes, are like no other visual organs found in animals. You can think of our vertebrate eye as a simplified, one-lens photographic camera with a sensor composed of millions of light sensitive cells (and a blind spot, mind you). Well, that’s nothing. Each insects eye is composed of several small photographic cameras, each with its own lens and light sensitive cells (albeit, commonly only six of these). These units are called ommatidia (sing. ommatidium), and the image if formed by the combined information from all of them.1
- To be honest, I have never know if this visual organ is called compound eye because it is composed of several ommatidia or because each ommatidium is composed of several elements. This has never disturb my sleep though. ↩
Last August, before taking a break from blogging, I posted an impossible-to-answer trivia. It consisted of the image above depicting an unidentified mysterious skeletal piece (sclerite) in the shape of a hook, together with two key pieces of information: a) it is entirely internal; b) it comes in pairs. › Continue reading
Archetype is about to get even quieter.
Grant proposals have been dealt with (more or less), and next week I will be in Turin, Italy, for the congress of the European Society for Evolutionary Biology. I just don’t want to won’t have time to blog during the congress, unfortunately.
But do not fear, for I leave you with a very tough quiz. Let see if someone knows what’s depicted below. A couple of tips:
- It is one of the few sclerites (skeletal pieces) in adult workers that is completely internal.
- It comes in pairs (left one pictured).
The answer will be revealed upon my return.
I have Google Alerts set for the term “cladistics” so I will receive a feed every time Google indexes that word. Now, in the last couple of days those feeds have catch a story circulating in the news media regarding a recently published study looking at the appendix from a comparative and phylogenetic perspective, pretty cool if you ask me.
I can only access the abstract of the original publication unfortunately, but it does seems to be a well done and thorough study. The problem is the way the report gets increasingly hyped by the news media. I first got this: Evolution of the appendix: A biological ‘remnant’ no more. OK, that’s not bad. I then got this: Appendix redux. Yeah, sure, succinct and clever. But today I got this: Darwin wrongly called the appendix a biological ‘remnant’, say researchers:
- Tom Waits