Go to Sweden. Learn about multicellularity. Taste dank saké.
I am hiring a PhD student to study the evolutionary origins of multicellularity. Apply here https://t.co/Ef77E4WbQX
— Eric Libby (@SFI_elibby) December 11, 2018
Eric Libby is looking for a Ph.D. student to model the evolution of multicellularity at Umeå University in Sweden. Here’s the project description:
The evolution of multicellularity is considered a major transition for the evolution of life on earth that made possible significant increases in organismal complexity. Somehow single-celled organisms, who were successful in their own right, evolved to form new kinds of individuals composed of many cells, multicellular organisms. While multicellularity has evolved on dozens of independent occasions, these events occurred millions of years ago and are absent from the fossil record. Recent experiments, however, have made it possible to study this pivotal event in the lab by using microorganisms to evolve primitive multicellularity de novo. Such experimental systems provide excellent opportunities to test hypotheses about the conditions that govern major transitions and facilitate the evolution of additional forms of complexity.
The goal of this project is to develop mathematical models that marry theory with empirical results to uncover general principles of how life evolves to be complex. Useful modeling techniques include differential equations, network approaches, agent-based simulations, evolutionary analyses, and probabilistic models.
Dr. Libby is a smart guy (and, full disclosure, an occasional collaborator), and this is an exciting opportunity for someone who wants to study the evolution of multicellularity. The application deadline is February 7, 2019. Information and application instructions are here.
If you’ll excuse an ignorant question… How do scientists know that multicellularity has evolved on multiple different occasions? I’m guessing it might be that they’ve found fossils of very early life forms in multiple parts of the earth, but I have no idea, and this sounds interesting.
That is a very not ignorant question. The short answer is the pattern of evolutionary relationships (phylogeny). Most multicellular groups are deeply nested within otherwise unicellular groups; in other words, their closest relatives are unicellular, their next-closest relatives are unicellular, and so on. When we talk about this or that multicellular ‘group’, we almost always mean a group of close relatives, or clade. These multicellular clades are scattered haphazardly throughout the tree of life, which is dominated by unicellular organisms. This tells us that the most recent unicellular ancestor of animals was different from the most recent unicellular ancestor of land plants, and from that of brown algae, and so on. If there were only one origin of multicellularity, we would expect a different pattern, namely that all multicellular organisms were more closely related to each other than to unicellular organisms.
Thanks! How do you tell which groups are related – I’m guessing by DNA analysis?
Is it known whether multicellularity has evolved via more than one mechanism?
These days it is mostly DNA, although things like comparative cell structure still play a role. There are at least two mechanisms, what Corina Tarnita and colleagues call “coming together” (aggregation, like slime molds) and “staying together” (clonal development, like plants and animals). If we get down to a finer scale, say what particular genes are involved, probably every multicellular group is unique.