Wednesday, May 18, 2005

Megalodon and the Great White Sharks: Conclusion

I had originally planned the first post in this series as a companion piece to the Cheetah post for the Friday Ark. One of the points I wanted to address was the issue of great whites preying on juvenile Megalodon. Since cheetahs have extremely high infant mortality I thought the two would complement each other nicely. Unfortunately, I got extraordinarily busy and didn't have time to do it then.
At any rate, I ended up somewhere else from where I intended. Originally, I was going to recount the evidence favoring the relationship with mako sharks, mention the predation on juvenile Megalodon and pretty much end it there. However this raised the broader question of what caused the extinction of Megalodon and I ended up talking about reproductive isolation between two populations of killer whales. Although I didn't perform any experiments or do any paleontological fieldwork, this is a good example of how science works. Start with a simple observation or question (Megalodon looks like a Great White - are they related?) find evidence (the characteristics of all those teeth as well as their position in the fossil record)then take stock of the implications of that evidence for your hypothesis (nope - not related). The evidence raised new questions (well then, if Megalodon didn't evolve into Great White sharks, then what happened to them (my answer: they were outcompeted by killer whales). At this point we could frame a new hypothesis and ask ourselves what kind of evidence would confirm or deny the theory (noticible absence of megalodon in areas with a lot of killer whale fossils or maybe a statistical analysis of the incidence of Megalodon in areas with great whites, bite marks on what few parts of Megalodon would fossilize, demonstration that the territories and niches of either great whites or killer whales overlapped with that of Megalodon - there are other, better types of evidence that would support or refute the idea, but you get the picture). then the process would start over, but at a higher, more general level. Whatever questions we asked of the data and whatever answers we received would apply at a wider, more generalized level till we ended up with...? (Hint: Something of great explanatory power that unites a wide variety of phenomena.) Note, though, that in this example, we did not work in a lab -we worked out in the field. Nor were we trying to explan something we personally witnessed (kind of like the resurection - no one saw that either - just saw an empty tomb and made assumptions - yes I'm feeling snarky) yet we are still able to make predictions and test our hypothesis.