![]() With the aid of complex statistical techniques, they were able to identify the optimal evolutionary model, given the nature of the available data, and correct for systematic errors. In their new study, published today in Proceedings of the National Academy of Sciences ( PNAS), Dr Pisani and colleagues used more powerful and sophisticated methods to analyse the genomic data presented in the earlier studies. Yet, one should be careful because complexity does not come out of nowhere either." "Granted, advocates of the view that ctenophores evolved first point out that evolution is not stepwise, and that is true. Even assuming the first animal was not a predator, how do we explain the evolutionary jump necessary to evolve a complex animal with brain and muscle from the single celled and colonial condition observed in our more distant eukaryotic relatives? For example, what was this ancestral predator predating upon? If it was the first animal, surely it did not have many targets on which to prey. If comb jellies came first, then the last common ancestor of all the animals might have had a nervous system, and as all comb jellies are predators this ancestor might have even been a predator. ![]() It is what makes us human, so is pretty important! Depending on whether sponges or comb jellies came first underpins entirely different evolutionary histories for this organ system. Take the nervous system for example this is the fundamental organ system that mediates our own perception of self. Recent genomic studies have suggested that comb jellies, members of the phylum Ctenophora, are the sister group to all animals but now new research, led by the University of Bristol, reaffirms the traditional view – that sponges (Porifera) are the oldest animal phylum.ĭr Davide Pisani of Bristol's Schools of Biological Sciences & Earth Sciences led a study, involving colleagues from Ludwig Maximilian University, Munich (LMU) and other institutes around the world, which reanalysed genomic data sets from three studies supporting the Ctenophora-sister hypothesis.ĭr Pisani said: "Knowing whether sponges or comb jellies came first is fundamental to our understanding of evolution.
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