Liveblogging the conference: Jon Seger 14 Mar 2008 Jon is a Utah biologist. His talk is on population genetics. He is talking about an unusually clean evolutionary experiment that leaves natural populations just as messy as they were before. Real populations are so complicated they frustrate basic models and general principles of population genetics. The whale lice of right whales are the case study used. The speciated about 5 million years ago and have distinct habitats.[Coalescent theory has completely changed how we do this work.] Okay: species are communities of genes, he says. Various problems – ring species, clines, yadda yadda. [Very pragmatic about species, as a good biologist should be.] Whale lice are crustaceans that form a white carpet on the surface of right whales. They have no free swimming stage so transmission is initially from mother to child. But some cross transfer from associates. There are three kinds of lice and three separate populations of right whales (Argentina, South Africa, Australia), and because we know the whale population and the number of lice per whale, we can a priori estimate the lice population. Almost no differentiation of lice between whales – they move so fast they are extremely well mixed. Drift is slow, as the population is large. But across the equator, isolation has made their mtDNA different, dating to the closing of the Isthmus of Panama. About one million years ago a southern whale moved across the equator introducing the southern lice to the northern Pacific population. The mtDNA is reciprocally monophyletic for that group – not so the nuclear genes. They have a coalescence date way back in the past – tens of millions of years. The mtDNA is recently coalescent. [I wish I could show you his figures.] Conclusions: marine lifestyles can “ablosh space”; given a large N drift is glacially slow; do they still belong to the “same” population if not gene flow for one million years? and genes and genomes coalesce at different rates; and probably no distinctive signatures in speciation events. Ecology and Biodiversity Evolution Species and systematics
Ecology and Biodiversity Rudd does too little on climate change 14 Dec 2008 I received this from GetUp today. I wonder if the politicians recognise that no amount of economic manoeuvring or political RealPolitik will avoid the laws of nature? If we do too little, then our children – not even our grandchildren but the very next generation – will suffer and badly…. Read More
Evolution Trashcan: chaotic remnants 7 Dec 2008 Siris has an interesting piece on the nature of the liberal arts. I loves me some 13th century, I does. Bora objects to Obama’s choices being characterised as “elites” and therefore bad. On the other hand, the term “groupthink” was coined to characterise the elite advisors of the first American… Read More
Epistemology Notes on novelty 2: Historical considerations – before and after evolution 18 Dec 201122 Jun 2018 Notes on Novelty series:1. Introduction2. Historical considerations – before and after evolution3: The meaning of evolutionary novelty4: Examples – the beetle’s horns and the turtle’s shell5: Evolutionary radiations and individuation6: Levels of description7: Surprise! 8: Conclusion – Post evo-devo The roots of novelty in biology are very deep. They go back at least to Aristotle’s book… Read More