BIOA02H3 Chapter : BGYA02 - Lec2 (text+lec combined notes)

• School: UTSC
• Department: Biological Sciences
• Course: BIOA02H3
• Professor: Mary Olaveson

Document Summary

All animals need nutrients and oxygen and must eliminate carbon dioxide and other waste products of metabolism. Under suitable circumstances, cells are protected from changes or harsh conditions in the external environment. Cells became specialized for maintaining specific aspects of the internal environment which enabled these specializations. Some cells evolved to be the interface between the internal and external environments and to provide the necessary transport functions to get nutrients in, move wastes out, and maintain appropriate ion concentrations in the internal environment. Other cells became specialized to provide internal functions (e. g. energy storage, movement). The evolution of physiological systems made it possible for multicellular animals to become larger, thicker and more complex and more adaptable to external environments. The maintenance of stable conditions (within a narrow range) in internal environment is called homeostasis. If a physiological system fails to function, homeostasis is compromised and as a result cells are damaged and can die.