Introduction to Ecosystems 



All organisms depend directly and indirectly on the activities 

 of other organisms for their survival and growth. The 

 relationships between diverse, and often seemingly unrelated, 

 organisms have evolved over millions of years to higher-order 

 complexes, called ecosystems. Ecology is the study of such 

 ecosystems. The goal of ecology is to understand and 

 quantitatively describe the fluxes of materials and energy between 

 functional groups of organisms, how the functions of these groups 

 affect the chemical and physical environment, and how the 

 environment, in turn, affects the function and structure of the 

 ecosystem. 



The Role of Molecular Biology in Ecology 



Because biological processes modify the chemical and physical 

 environment, understanding how ecosystems function is crucial in 

 predicting the effects of potential change on the future 

 environment. Fundamental insights into how organisms function, 

 respond to short-term change, and ultimately evolve, lie in their 

 genetic material. A thorough understanding of ecosystems requires 

 a knowledge of molecular biology, the study of the function and 

 regulation of genes and their products. When integrated into 

 higher levels of ecological research, molecular biology can provide 

 basic information on the regulation and mechanisms of key ecosystem 

 processes. Such information is crucial in developing predictive 

 models of how ecosystems will respond to energy-related activities 

 on global and local scales. 



The Scaling Problem 



Darwin's theory of evolution by natural selection, developed 

 in the mid 19th century, provided the conceptual basis for 

 ecosystem research. The elucidation of the structure and function 

 of DNA by Watson and Crick in the late 1950s was a watershed for 

 modern molecular biology. While biologists basically understand 

 that gene function and regulation are ultimately related to how 

 ecosystems evolve and function, integration of that information 

 into ecological understanding has been slow, primarily due to 

 compartmentalization and specialization within biological 

 subdisciplines . 



