Biomaterial Database

[Evolution of the circadian organization (author's transl)]. 1978

E Bünning

The evolution of cicadian rhythmicity was possible by selection and mutation. Rhythms which strongly deviate from the circadian rhythms are still existent in case no selective pressure has occurred. An evoluution regressive to those strongly deviating rhythmus can be observed in case the selective pressure has disappeared. The circadian rhythmicity in the various cells and organs of multicellular organisms has not got lost during the evolution. But certain organs have grown important for maintaining the circadian organization within the body and for allowing the synchronization with the light-dark cycles. In addition, contrary to lower organisms, certain processes, e. e. photoreception, are coupled to the circadian rhythm only in specially differentiated organs. The high precision in the clock's running within higher organisms becomes possible by mutual synchronization within the multioscillator system.

UI	MeSH Term	Description	Entries
D002940	Circadian Rhythm	The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs or environmental and physiological stimuli.	Diurnal Rhythm,Nyctohemeral Rhythm,Twenty-Four Hour Rhythm,Nycthemeral Rhythm,Circadian Rhythms,Diurnal Rhythms,Nycthemeral Rhythms,Nyctohemeral Rhythms,Rhythm, Circadian,Rhythm, Diurnal,Rhythm, Nycthemeral,Rhythm, Nyctohemeral,Rhythm, Twenty-Four Hour,Rhythms, Circadian,Rhythms, Diurnal,Rhythms, Nycthemeral,Rhythms, Nyctohemeral,Rhythms, Twenty-Four Hour,Twenty Four Hour Rhythm,Twenty-Four Hour Rhythms
D005075	Biological Evolution	The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.	Evolution, Biological
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001683	Biological Clocks	The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.	Biological Oscillators,Oscillators, Endogenous,Pacemakers, Biological,Biologic Clock,Biologic Oscillator,Biological Pacemakers,Clock, Biologic,Clocks, Biological,Oscillator, Biologic,Oscillators, Biological,Pacemaker, Biologic,Pacemakers, Biologic,Biologic Clocks,Biologic Oscillators,Biologic Pacemaker,Biologic Pacemakers,Biological Clock,Biological Oscillator,Biological Pacemaker,Clock, Biological,Clocks, Biologic,Endogenous Oscillator,Endogenous Oscillators,Oscillator, Biological,Oscillator, Endogenous,Oscillators, Biologic,Pacemaker, Biological