Introduction There are adverse ecological effects of genetically engineered organisms in the environment. However, they have varying effects on the environment. Nonetheless, both natural plants and animals are affected by these side effects. However, apart from the side effects on animals and plants, there are general degradation of the ecosystem that results from the associated activities of genetically engineered organisms. The potential gains of these organisms are usually offset by their negative ecological effects. Therefore, this paper covers ecological effects of genetically engineered organisms stressing specific effects of organisms on natural plants and animals in their respective ecosystems. Ecological Effects of Genetically Engineered on Natural Plants’ Ecosystems Globally, genetically engineered plants have drastically increased in terms of their vegetative cover, thus covering a substantial global area. However, according to Conner and Nap (2003), there are several concerns that genetically engineered crops have adverse negative ecological effects. Nonetheless, there are several reasons that have contributed to their widespread adoption by several countries. Some of these reasons include insect resistance characteristics and the herbicides tolerance that the crops have. Another common reason for adoption of these crops are their high yielding features. Thus, it is hoped that through them, the world can be able to solve food shortage problems that usually characterize developing countries. On the other hand, there are several adverse ecological effects that are associated with these plants which surpass the highlighted benefits. To begin with, genetically engineered plants have been established to have negative effects on biodiversity. According to Robinson and Sutherland (2002), concerns have been raised that genetically engineered plants have negative impacts on the soil organisms. Beneficial soil organisms such as earthworms, mites, nematodes, woodlice among others are some of the soil living organisms that are adversely affected by introduction of genetically engineered organisms in the ecosystem since they introduce toxins that are lethal to the survival of these organisms. Moreover, with application of genetically engineered plants in the ecosystems, it has been established that there is a potential flow of genes from genetically engineered crops to the natural wild crops. Therefore, spontaneous mating of these two crops categories posses threats of extinction of natural wild plants in these ecosystems. This is likely to lead to formation of transgenic plants that will replace the entire wild plants in the ecosystem hence resulting in clear extinction of natural species. Nonetheless, in respect to this, there are also risks of genes’ imbalance to crops that results from transgenic plants (Huang et al., 2003). Therefore, with the widespread adoption of genetically engineered plants, the world is likely to witness genetic alteration of the vegetative covers. This is likely to result to irreversible state of vegetative genetic makeup hence having drastic ecological impacts in future. Furthermore, according to Robinson and Suthe