Dinosaur was simply lucky!!!
Natural selection proposed by Charles Darwin’s was challenged by many in the past and things in the future also might not change.I don’t think we need any more evidence for Natural selection, as we have already huge data confirming its role in evolution.>
This week’s Science contains a paper by Brusatt et al. (2008) discussing the evolution of dinosaurs. They found no evidence that the dinosaurs were evolving more quickly or were becoming better adapted when compared to other vertebrates of that time and the reason for them surviving the test of time was just luck.
Unfortunately being a developmental biology student i never got so much time and chance to read original book ” origin of species” completely (which i might in future for sure) ,so i am not in a situation to say what exactly Darwin said about on the role played by chance and luck or accident in evolution of species. I believe that even though natural selection is the major driving force of evolution ,but the scope for chance, luck, and accident in evolution cannot be ruled out.The work of Brusatt et.al could be an example of luck and chance.
Dinosaurs illustrates a perfect example of both success and failure.Success in terms of them dominating terrestrial ecosystems for well over 100 million years and failure because of their extinction 65 million years ago.Most popular belief among scientists for Dinosaurs becoming a force to reckon with during the Jurassic era is due to the presence of some characteristics that helped them out-compete other vertebrate groups.
Brusatte et al. measured evolution rates, speciations, and morphological disparity for the two groups (crurotarsans and dinosaurs) before the Triassic-Jurassic extinction event.Unlike today’s crocodiles, Triassic crurotarsans were amazingly diverse. There were enormous quadrupedal predators, slender bipedal predators, swift bipedal omnivores, fish-eaters, root-grubbers, and low-to-mid-browsing herbivores. Many of these crurotarsans look nothing like crocodiles.They found no difference in the rates at which dinosaurs and crurotarsans were evolving.
This was surprising as, if dinosaurs were truly ‘superior’ or ‘out-competing’ crurotarsans in the Triassic, they should be expected to evolve faster. Instead, crurotarsans were keeping pace.
“Why did crurotarsans go extinct and not dinosaurs? the authors don’t know the answer to that, but suspect that it was nothing more than luck, plain and simple.”
Larry Moran nicely summarize the important aspect of the work on his blog sandwalk :
“if you rewind and rerun the tape of life it will not turn out the same. A lot of the history is due to chance, luck, and accident.”
The original press release can be read on science daily
Brusatte, S.L., Benton, M.J., Ruta, M. and Lloyd, G.T. (2008) Superiority, Competition, and Opportunism in the Evolutionary Radiation of Dinosaurs. Science 321:1485-1488.