Convergence; another example (Introduction)

by dhw, Saturday, May 24, 2014, 20:25 (3836 days ago) @ David Turell

DAVID: Comb jellies have nerves, apparently developed separately from other evolved organisms.-http://www.genomeweb.com//blog/more-once-"The researchers also argue that, since the comb jelly is missing many of the usual pieces of the nervous system — the Pacific sea gooseberry uses one or two neurotransmitters rather than all 10 of the primary ones seen in other animals, Nature News notes — it may have evolved independently.-"Everyone thinks this kind of complexity cannot be done twice," first author Leonid Moroz from UF tells Nature News. "But this organism suggests that it happens.'"-As always, I'd like to thank you for the flow of information. You are providing us with an on-going education! So I hope you won't think I'm ungrateful if I use your material to pursue certain arguments.-I agree that this an example of convergence. It also seems to me to be an example of evolution "spraying inventions in every direction" (your own expression) in an evolutionary free-for-all, rather than of "antedating need" and "pre-planning" (again your own expressions). See under "Innovation and Speciation: pre-planning".