 The study of population and community biology frequently involves the 
          use of "model systems" to learn the details of ecology and evolution. 
          Below we provide a link to the three-trophic-level goldenrod, gall-inducing insect herbivore, natural enemies model system. Work with such systems is contributing important 
          understanding of ecological and evolutionary principles or phenomena.
 The study of population and community biology frequently involves the 
          use of "model systems" to learn the details of ecology and evolution. 
          Below we provide a link to the three-trophic-level goldenrod, gall-inducing insect herbivore, natural enemies model system. Work with such systems is contributing important 
          understanding of ecological and evolutionary principles or phenomena. 
          
          Goldenrod 
          Ball Gall Model