1 homeostasis 118 - environment as constant as possible a...

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Biology 118 1. ORGANIZATION AND HOMEOSTASIS THE POWER OF TEAMWORK : consider how form affects function at every organizational level. Chemical – atoms join to form molecules. Cellular – molecules join to form organelles and other parts of cells. Tissue – cells join to perform specific functions. Organ – tissues join to work together. Organ system – a number of organs work together. Organism – many organ systems work together to keep an individual alive. INSIDE, OUTSIDE, HOMEOSTASIS : Any organism has two environments to cope with: the external, and the internal. For the organism to survive, there must be a constant exchange between these two environments. The external environment is prone to wide fluctuations, or changes, while the organism wants to maintain its internal
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Unformatted text preview: environment as constant as possible a steady state called homeostasis. This is why changes in the external environment are often challenges or stimuli for organisms. Organisms have homeostatic mechanisms to cope with these challenges. Negative feedback is employed to minimize flux in the internal environment: A stimulus (fluctuation) starts a chain of communication between a sensor, a control center and an effector. The effector will try to counteract, or correct for, the initial stimulus. There are also positive feedback loops. This is where the initial stimulus triggers a response that reinforces or intensifies the stimulus....
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This note was uploaded on 11/02/2011 for the course BIO 118 taught by Professor Bilgen during the Winter '08 term at University of Washington.

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