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Updated: Oct 7, 2026

Measurement of Lifespan in Drosophila melanogaster
Published on: January 7, 2013
Abstract:
Life is defined as a "condition" that distinguishes animals and plants from inorganic materials and dead organisms. Life is comprised of processes and is a maintained state. The most sophisticated form of life is man and our though focuses upon the nature of the life and death of man. Man demonstrates three lives or aspects of life: Life of the body--the physical, life of the mind and life of the spirit. Physical life is basic existence; the mind contributes effectiveness and scope; the spiritual entity contributes maximum living. Physiology: The existence of life physical is demonstrated by the presence of functions. Living tissues and organisms exhibit: Irritability: the ability to be excited or detect stimuli and to respond thereto; Growth and reproduction: this consists of the power of multiplication and duplication, regeneration and differentiation; Adaptability: permitting both change and maintenance of balances (homeostasis); and finally and most characteristic of all is Metabolism: the transformation of energy and the use of materials. These properties, however, can be retained for a while by tissues after death of the organism so there is another mystery of life which we understand only in part. Life consists of structure and processes operating under integrative control. This integrative power is the secret we do not understand--we know it confers all the life properties, the continuous flow of processes related to the organism's need for survival. Death is failure not so much of process but of integrative drive and coordination--but, of course, structure and process can fail too, destroying integrated activity. The total organism is under integrative control by brain and mind, the autonomic nervous system and by the neuroendocrine-endocrine complex, all acting in unison. These physical processes contribute to the existence of the life of the mind and spirit and are in turn powerfully affected by intellect and morale. However, we do not understand the driving force which converts inorganic matter, organizes it and then propels it into life. Life seems to be only a continuation of a heritage--life creating life. Philosophy: The life of the mind requires acquisition of knowledge, curiosity, cultivation of the power to reason, use of thought and contemplation, all under discipline. True life of the mind may not exist and may cease to be even though physical existence may be present. Somewhat the same can be said of the life of the spirit; it also is not automatically genetically granted in completed form.(ABSTRACT TRUNCATED AT 400 WORDS)
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