This was my definition:
"An environmentalist is a person who is dedicated to their cause, is education and is motivated to change the world and it's environment for the better".
(For those who don't know who Tim Treadwell is, this wikipedia article should explain the basics.  )
Here is the essay I wrote.
Tim Treadwell: Environmentalist or Nutcase?
Is Tim Treadwell an environmentalist? My definition of an environmentalist is "A person who is dedicated to their cause, is educated and is motivated to change the world and it's environment for the better." Even though Treadwell is very dedicated to the grizzly bears, and he is educated, he is not trying to change the world for the better. He seems to be out in the wilderness mainly for personal gain, having the experience of living with the creatures he loves. He also is causing more harm to the bears than he caused good. Also, he is not promoting environmentalism, it seems he is just promoting his adventures with bears. For these three main reasons, I believe Tim Treadwell was not an environmentalist, but a nutcase.
In the documentary made about his life titled "Grizzly Man", it was hinted at multiple times that Tim seemed to be trying to find himself and personally gain knowlage about his self. He took multiple takes of many scenes, as shown in the documentary, almost as if he was trying to make a movie out of his recordings . It looked like he was more concerned with making it look good rather than making it look real. It was also assumed that Tim actually wanted to become a bear himself, an impossible feat for a human being. He treats the bears lke members of his family, even giving each individual bear their own names. His friends and family supported him on his trek to live with the bears, but Tim took it much farther than anyone could have ever imagined, and in that journey I feel he lost the objective of teaching the world about the grizzly bears and started caring too much about finding himself.
During his time out in the wilderness, Treadwell caught a lot of attention from the citizens of Alaska as well as the authorities. He even went on a few popular television shows like The Dave Letterman Show. All this popularity he aquired proved to be a large negative when it came to helping the bears, if that is what he intended to do. As shown in the documentary, people actually adventured out into the wilderness where Tim stayed, and started harming the bears trying to trick Treadwell to confront them. Along with hassling the bears, they also defaced wildlife by carving messages and creepy smile faces into logs. If Tim had not brought all this attention to the bears, the poachers would have much less motivation to come out and look for him. Not only did the attention bring harm to the bears, Tim himself invading the bear's territory also caused harm to the bears. He prevented some of the bears from being agressive with him, possibly disallowing them to gather food or claim territory. This is not a good thing to do with bears, considering they are very territorial and need a lot of food to keep running. If that wasn't enough, Tim didn't even have legal permission to be out there living with the bears. Since he was partially living in a part of a National Park, he would be required to report to the park managers. Of course the managers would have denied to let him live with the bears, but for a good reason. They knew a man living out with the bears would cause more harm than good. This is just one of the many reasons I believe Tim Treadwell is not an environmentalist.
The biggest reason I believe that Tim Treadwell is not an environmentalist though, is because he is not really helping the environment in my eyes. Yes, he is going to schools and teaching the kids about the grizzly bears, but simply teaching kids about an animal is not being an environmentalist. If this was the case, you could say almost every teacher who teaches about animals, science or any other subject that has things to do with the environment is an environmentalist. This is simply not the case. My definition of an Environmentalist clearly states, "... is motivated to change the world and it's environment for the better." Teaching is not changing the world/environment, it is simply providing knowlage to those who choose to listen. Along with that, Tim doesn't really seem to want to improve the world/environment aside from educating the kids. He seems like the kind of person who has a few screws loose in his head and wants attention because he does something that is not normal in the world.
After all this research and studying, I do not believe Tim Treadwell is an environmentalist. He seems to be living with the bears for his personal gain rather than to help them, and is causing more harm than good to the grizzly bear community. He is not promoting environmentalism, only knowlage of bears, and he does not fit my defintition of an environmentalist. He may be dedicated, and he may be educated but he is simply not trying to change the world for the better. Treadwell is simply a man who thinks he is doing something important for the environment, yet all he is doing is making people like me think he is a nutcase.