The document discusses the costs, benefits, and consequences of interactions between species and with the environment. It explains that most symbiotic relationships exist in a stable balance, but that this balance can be impacted by the health of the host organism or environmental conditions. It provides examples of how factors like overcrowding or humidity can negatively impact hosts like seedlings or raspberries. The document also discusses how humans manage these relationships through improving environments, using drugs, pesticides, and herbicides.

1. The Costs, Benefits and Consequences of Interactions - Interaction between species - Interactions with the environment We have studied various types of biotic interaction that exist between species in an ecosystem. Now we are going to look at these interactions again, but this time we are going to concentrate on the COSTS , BENEFITS and CONSEQUENCES that these interactions have to the different species

2. Interactions between species: SUMMARY

15. Response curve Although organisms can tolerate a range of external environmental changes, they function most efficiently at certain optimum environmental conditions. An organism's responses to a changing environmental factor can be studied in the laboratory and a tolerance, or performance, curve can be produced