1. Read through the report titled "Ecosystem Services: Benefits Supplied to Human Societies by Natural Ecosystems" published by the Ecological Society of America.
   
   Summarize the various ecosystem services that benefit humans. What are some of the threats to ecosystem services? What does the report state on the value of ecosystem services to humans?
   
   
2. Read an excerpt from the 1993 book "Valuing the Earth: Economics, Ecology, Ethics" by Herman Daly and Kenneth Townsend.
   
   How does the excerpt differentiate between "sustainable growth" and "sustainable development"? What policy does the excerpt suggest for maintaining throughput levels? Why should both "optimists" and "pessimists" welcome this policy? According to the excerpt, how should renewable and non-renewable resources be used?