Wednesday, October 13, 2010

Factors Affecting the Extinction of Species

Ecosystems rely on every aspect of that ecosystem. This includes the different kinds of species that inhabit those ecosystems. If a species becomes extinct, it could result in many different ways that are possibly detrimental to that ecosystem along with the biodiversity of that ecosystem and in turn affect humans. Human activity has a major impact on all different kinds of species. The species of the Earth are affected in so many ways, such as global warming, destruction of habitats and the overexploitation of the ecosystems that the species dwell in. The study conducted at the University of Auckland in New Zealand, along with the University of Dalhousie in Nova Scotia simulates just how these affect a certain species. Humans are a huge threat to the biodiversity of the world’s ecosystems. We are a main cause of rapid global warming because we emit such large amounts of carbon dioxide and other pollutants. Also, humans cause habitat fragmentation, or the destruction of habitat, for reasons such as land development and agriculture. Another reason that follows is due to overexploiting the lands resources, which means that we harvest a resource to the point where it is destroyed. Camilo Mora displays with multiple simulations of how the effects of human beings can be terrible for the different species of the Earth.

This study was conducted in a way that simulated real life. The specimen that was chosen was Brachionus plicatilis, which is a rotifer species (also known as a ‘wheel animals’) because they are easy to culture in a man-made environment. Also, this species is able to thrive easily in a changing environment, so this species will demonstrate very convincing data because it should show that not even a species such as this can thrive under these conditions. Simulating a natural environment with twelve hour intervals of light and at an average temperature of 25 degree Celsius provided ideal conditions for the growth of this species.

The three suspect reasons of species extinction were all measured individually and in all possible combinations. Warming was simulated by the increase of temperature and was accurate to 0.1 of a degree. The habitat fragmentation was controlled by the amount of immigration of other species. The logic here is that when a habitat is destroyed, the distance between the neighboring habitats has been increased, and therefore there is less migration. Immigration increases the amount of variation in diversity and therefore the species are not able to thrive as easy. Thirdly, the overexploitation was controlled by removing a certain amount of this species. This is because when one takes away all the resources, one also takes away many individuals of that species and in turn, the species loses diversity in itself and therefore are less likely to thrive. Instead of taking away the species indirectly, it has been done directly.

It turns out that all the variables of this study had a negative effect on the populations of the future generations, although certain combinations had an effect that was not just adding the two together. For example, for both individual effects of warming and deprivation of immigration there were about 15 percent decline. One would expect a decline of 30 percent. Although, the results show that there was an approximate 50 percent decline. This was also true for warming and overexploitation there was a 50 percent decline in the populations of future generations. However this was not true for the combination of overexploitation and deprivation of immigration. This only had an additive result, in other words, the two 15 percent declines were added together to make about a 30 percent decline. When all three variables were applied to the populations, there were not any significant declines, even though it was the most dramatic decline of about 70 percent.

It is concluded by these researchers that warming was the greatest factor in the extinction of species. However, all of the variables had a significant impact on the population of this certain species. These variables are very real conditions in today’s environment. Global warming is only increasing, along with overexploitation and land clearing. Pollution is increasing drastically, and humans are only using more and more resources and clearing more and more land. These are perfect conditions for the extinction of many species, and these are partly the reasons for recent extinctions. To prevent the extinction of further species, human’s as a whole must cut down on the emission of pollution, and things such as deforestation, land clearing and development.

Work Cited

Mora, C., Metzger, R., Rollo, A., Myers, R.A. 2007. Experimental simulations about the effects of overexploitation and habitat fragmentation on populations facing environmental warming. Proceedings of the Royal Society B, 247: 1023-1028.

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