Theory

phyloseminar.org – February 24th, 1pm (PST)

Tuesday, February 23rd, 2010 | Cladistics, Education, Science, Theory | Comments Off on phyloseminar.org – February 24th, 1pm (PST)

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Do not forget to tune in to tomorrow’s phyloseminar where Noah Rosenberg will be speaking about consistency properties of species tree inference algorithms under the multispecies coalescent. February 24th at 1pm PST.

You can watch him live from the comfort of your computer, but you may want to take some minutes before the seminar to set up your computer and microwave some popcorn.

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Phylogenetics through videoconferencing

Tuesday, December 8th, 2009 | Cladistics, Education, Theory | 4 Comments

phyloseminar1Last night I attended a talk in Lisbon given by Ward Wheeler at the AMNH in New York City and moderated by Frederick Matsen from his home institution in Berkeley, California. The talk was the second on a series of talks in phylogenetics held via videoconferencing.

The idea behind phyloseminar.org is to hold regular live online seminars in phylogenetic methodology open to anyone around the globe. This is a challenge given the time zone differences of the possible participants, but it does makes the whole event fun: I watched it after dinner at 9:00pm; the presenter gave it at his 4:00pm; while the moderator was there after lunch at his 1:00pm. I saw at least one person among the audience that watched it from the future after breakfast in New Zealand the next day at 10:00am. › Continue reading

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Evolution and development of castes in ants

Thursday, November 12th, 2009 | Ants, Comparative Anatomy, Morphology, Theory | 6 Comments

Manica - castesUp 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.

› Continue reading

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Counterintuition in Biology

Thursday, October 1st, 2009 | Metablogging, Philosophy, Theory | 2 Comments

haeckel RotatoriaOver at Evolving Thoughts, the mighty white gorilla from the Antipodes (that sometimes goes under the nom de plume John Wilkins) has paused from his grand World Tour 2009 to write a nice and succinct reflection on the nature of concepts and definitions in Biology. He writes:

We ought not to think that a conception or definition or hypothesis that works in one part of biology must work in all others, and yet biologists themselves often behave as if this were true. That is another challenge: why is this? The answer, I believe, is that biology is both highly diverse, and also massive.

Read the rest in his post: Counterintuition: Bdelloid Rotifers « Evolving Thoughts.

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WTF?

Friday, September 4th, 2009 | Ontogeny, Phylogeny, Theory | 5 Comments

Can someone please tell me if August 28th is the equivalent of “April’s fool day” somewhere in the world? This paper just published online in the Proceedings of the National Academy of Sciences (USA) reads like something coming out straight from The Onion:

Published online before print August 28, 2009, doi: 10.1073/pnas.0908357106

Caterpillars evolved from onychophorans by hybridogenesis

Donald I. Williamson
Marine Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom

Abstract:
I reject the Darwinian assumption that larvae and their adults evolved from a single common ancestor. Rather I posit that, in animals that metamorphose, the basic types of larvae originated as adults of different lineages, i.e., larvae were transferred when, through hybridization, their genomes were acquired by distantly related animals. “Caterpillars,” the name for eruciforms with thoracic and abdominal legs, are larvae of lepidopterans, hymenopterans, and mecopterans (scorpionflies). Grubs and maggots, including the larvae of beetles, bees, and flies, evolved from caterpillars by loss of legs. Caterpillar larval organs are dismantled and reconstructed in the pupal phase. Such indirect developmental patterns (metamorphoses) did not originate solely by accumulation of random mutations followed by natural selection; rather they are fully consistent with my concept of evolution by hybridogenesis. Members of the phylum Onychophora (velvet worms) are proposed as the evolutionary source of caterpillars and their grub or maggot descendants. I present a molecular biological research proposal to test my thesis. By my hypothesis 2 recognizable sets of genes are detectable in the genomes of all insects with caterpillar grub- or maggot-like larvae: (i) onychophoran genes that code for proteins determining larval morphology/physiology and (ii) sequentially expressed insect genes that code for adult proteins. The genomes of insects and other animals that, by contrast, entirely lack larvae comprise recognizable sets of genes from single animal common ancestors.

I think Lynn Margulis went too far this time…

Minelli on morphological homology

Thursday, June 11th, 2009 | Comparative Anatomy, Theory | Comments Off on Minelli on morphological homology

In the absence of specific arguments to the contrary, shared patterns of gene expression should not lead us, per se, to homologise organs that a comparative morphologist would never try to compare.[p.23]

Alessandro Minelli 2003. The Development of Animal Form: Ontogeny, Morphology, and Evolution. Cambridge University Press. Cambridge.

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Evolution today and tomorrow – Lisbon’s conference

Sunday, April 26th, 2009 | History of Science, Personalities, Theory, Web | Comments Off on Evolution today and tomorrow – Lisbon’s conference

I spend last Thursday and Friday attending a conference held at the University of Lisbon: Evolution today and tomorrow: Darwin evaluated by contemporary evolutionary and philosophical theories. 23 – 24 April 2009. Don’t let the event’s webpage design fool you, the conference was well organized and brought together a diverse array of interesting speakers, both Portuguese and from abroad. › Continue reading

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Pre-Darwinian Homology

Thursday, January 22nd, 2009 | Theory | Comments Off on Pre-Darwinian Homology

In a recent post Anastasia Thanukos for bringing up the concept of common ancestry into the definition of homology. Their criticism seems a little harsh to me since, as they noted, the paper is aimed at Science teachers and it is therefore written on a “text-book” tone. This issue aside, however, I find their complain somewhat out of touch. › Continue reading

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