Biology 2483A Lecture : "The Physical Environment"
25 Aug 2013
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Document Summary
Certain earth regions have organisms that have adapted for survival for millions of years. The physical environment ultimately determines where organisms can live, and the resources that are available. Thus, understanding the physical environment is the key to understanding all ecological phenomena. The life of a salmon is quite an adventure from the moment they are born in small streams they journey to the ocean, only to return to their freshwater birthplace. They are a very economically important species in our society. The potential causes of salmon declines in the north pacific ocean include: dam construction, sediment from logging operations, water pollution, and overharvesting. But the conditions of oceans, where salmon spend most time as adults, have also been implicated. Hare and francis (1994) studied fish harvest records and showed alternating periods of high and low production associated with climatic variation in the north pacific. The trends in salmon populations are intimately connected to climate changes.
