Ok I saw this movie once years ago and i friggin hated it, it was stupid. It was recently on tv and I got sucked into watching it again. I had forgotten how much I hated the movie and I feel the overwhelming urge to rant, yet again. C'mon, you know me I gotta let this shit out.

The reason for my hatred of this movie isn't so much the acting or the visual effects or anything like that, it's the blatant smack in the face of lack of biology. I mean this movie's cast of characters consists of marine biologists and scientists and other supposedly smart people but I guess they didn't think to consult any real ones before making this garbage. I usually don't have too much of a problem suspending my disbelief for movies, I'm a fantasy fan and you can't get much further from reality than that. When it comes to some movies that try to look educated and scientific but make very large mistakes in simple Physics or other areas of science, I can't ignore those kinds of gaping plot holes and enjoy the movie.

The basic plot is that apparently a shark's brain contains a chemical which can cure Alzheimer's disease, so they make the shark's brain bigger so they can mine more of the chemical. As a side effect the sharks got smarter. Well, DUH! What, they increase the creature's brain mass and they didn't expect any side effects? That's some pretty crappy science work there. Rule number 1 is always map out any possible side effects. Best case scenario: nothing happens, worst case: shark dies. I guess they didn't think of the grey area in between?

Besides the tremendous DUH moment there which had me rolling my eyes the worst part was yet to come. At one point later they show a shark swimming backwards. Yes, you read me right, it swam BACKWARDS! My eyes flew open in disbelief when I saw that. I sat there saying "Tell me I didn't just see what I thought I saw." Then one of the characters says "I didn't know sharks could swim backwards" and I shouted "That's because they CAN'T!!!" It is physically impossible for a shark to swim backwards and no amount of boosted intelligence will change that. You could clone Einstein's brain and transplant it into a shark and it still wouln't change the fact that they are physically incapable of backwards locomotion. The same way a fish can't ride a bicycle or an elephant can't climb a ladder a shark CANNOT swim backwards. Their tail, their only source of propulsion, swishes side to side, driving a shark forward and only forward. A shark cannot make it's tail move in any other direction which would enable it to move backward. To prove my point you can try this simple experiment at home (and I hope I can explain this part properly). Make a fan out of a piece of paper (or if you have a hand fan already you can use that) and fan yourself with it. See how it blows the air directly towards you. Now, with the fan still facing you, make the fan blow the air in the opposite direction, away from you. It can't be done. You'd have to change the position of the fan so that it was facing away from you. The same is with a shark, for it to be able to swim backwards it would have to remove it's tail and attach it to it's nose. It would of course suffocate quickly because the water would be flowing over it's gills backwards and it wouldn't be able to breathe. If this movie's writers had bothered to do any actual science other than what would look cool they would have figured that out. Plot holes like that one ruin a movie for me. /sigh

The worst part of this is that there are many other movies out there that have a huge hole in the basic science. There are other things that a movie can do to be more exciting and shocking without changing the laws of physics.