Ethan A. Huff writes in Natural News:
Most vegetarians believe that by not eating animals, they are preserving life. Everyone knows that plants are alive but they are not viewed with the same level of intelligence as animals are. As science continues to uncover the complex nature of plants, it is becoming more apparent that plants are actively intelligent life that pursue their continued existence in similar ways as do animals.
Research on the subject naturally flies in the face of strict vegetarianism which often insists that eating animals is murder but eating plants is just fine. Yet the facts illustrate that the characteristics of animals used to argue that eating them is murder also apply to plants. In other words, in order for strict vegetarians to be consistent in their beliefs, they would also have to stop eating fruits and vegetables.
Plants are very sensitive to environmental changes and they have many built-in mechanisms to ward off attackers.