Natural Resources And RecyclingThe Earth is a closed system. For our examples, we need to think that nothing comes in (except energy) and nothing goes out (except energy). Even the amount of energy that moves in and out of the Earth is equal. If more came in than was released, we would heat up. If the Earth gave off more energy than it received, we would cool down. The smarties in the crowd are saying "What about meteorites?" Yes. There are small amounts of matter hitting the Earth from space. On the other hand, we are sending more satellites and spacecraft into orbit. A little is being lost too.
The big point of this section is to look at the idea that humans have a finite amount of material on this planet. We call these materials natural resources. Not only are humans using these materials, but nature is using them too. The difference between humans and nature is that nature doesn't waste. Materials are cycled through the ecosystems of the Earth and reused whenever possible. There have been points in time where nature runs out of things and it adjusts, changing ecosystems or the types of organisms that survive. Think about water for a second. Many places used to have large freshwater lakes with thriving communities. Over thousands of years, those lakes dried up and some even became deserts. Nature didn't just give up, with the change in environment, new organisms began to thrive and the ecosystem changed.
Humans may be doing that as we speak. We use natural resources, but don't return them to the system. They may wind up in landfills or at the bottom of the ocean. If we have a finite amount of resources, there is always the possibility that we will run out. Nature will continue. The organisms that survive will change. But we might not be one of them. Don't worry about it this afternoon. We have plenty of stuff for a long time.
The big point of this section is to look at the idea that humans have a finite amount of material on this planet. We call these materials natural resources. Not only are humans using these materials, but nature is using them too. The difference between humans and nature is that nature doesn't waste. Materials are cycled through the ecosystems of the Earth and reused whenever possible. There have been points in time where nature runs out of things and it adjusts, changing ecosystems or the types of organisms that survive. Think about water for a second. Many places used to have large freshwater lakes with thriving communities. Over thousands of years, those lakes dried up and some even became deserts. Nature didn't just give up, with the change in environment, new organisms began to thrive and the ecosystem changed.
Humans may be doing that as we speak. We use natural resources, but don't return them to the system. They may wind up in landfills or at the bottom of the ocean. If we have a finite amount of resources, there is always the possibility that we will run out. Nature will continue. The organisms that survive will change. But we might not be one of them. Don't worry about it this afternoon. We have plenty of stuff for a long time.