Invasive

An invasive species is an alien species whose introduction does or is likely to cause economic or environmental harm to Human health. An introduced species, plant or animal that out competes native species for space and resources. The first definition caught me off guard since I have never thought of it that way. The second definition is the one I am more familiar with. With this in mind I’ve always thought Humans are the most successful invasive species ever. We colonize new areas pushing out native species and we have spread throughout the world. We destroy natural ecosystems wherever we spread our cancerous roots and have devastated Earths Geo systems.
After the most recent ice age Humans were almost wiped. The drop in world temperature caused drought and food supplies to diminish; in turn Humans suffered famine and drought. At about 10,000 BC Human population was in the range of 1,000- 2,000 and now our population is at about 6.75 billion. In just around 12,000 years this is a huge population growth. At the peak of population growth the human population was growing at a rate of 2.2% a year. Currently human population growth is at 1.2% a year. The human population is now so emence our actions are having a huge impact on the world, natural habitats and geo systems. Because of the pollution we produce the earth is changing at an alarming rate. The polar ice caps that took thousands of years to make will be completely gone within the next hundred years.
Many scientists believe that human population has grown beyond Earths limit to support life. This is true and at this point humans are using earths natural resources two times as fast as these resources are being naturally replenished. We have destroyed natural habitats and have been decimating earths natural resources for thousands of years but this will end. Human life is dependant on certain global conditions and without the right conditions human life can easily be snuffed out. Humans are one of the most effective invasive species to roam the earth but human life will not last but the earth and simple organisms will.

References
-http://en.wikipedia.org/wiki/World_population
-http://math.berkeley.edu/~galen/popclk.html
-Geology 101 lecture by Mike Folley