2

Tropism, the change in movement or makeup due to an internal or external stimulus. The stimulus could be the sun, for example. Many plants will bend and move towards the sun light. They want to achieve just the right amount to UV input. Tropism due to an internal stimulus could be a virus or variance in genetic makeup. Viruses can cause cellular tropism which leads to transformation or mutation. Mutations can also occur when a gene randomly changes due to unusual environmental conditions or just for no reason at all. Due to this tropism in the plants, genetically strong and adaptable plants will like and the others will die. This is the basis of evolution and the exact process that lead to the initial notion that things change for a reason. Tropism in plants creates new and better varieties, this creation is nature's art.