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Background: The concept of allometry states that the relative rate of change of a system unit is a constant fraction of the relative rate of change of the entire system, or of another part of the system.This concept is stated as a nonlinear relationship and has been verified in a variety of natural systems.
Materials and Methods:The allometric relations in various phases of basin evolution in forms of static and dynamic models wasinvestigated.In order to study the dynamic allometry, a model consistingof two basins was developed.The evolution stages and the erosion changes caused by artificial rainfall and tectonic movements and also in static form (natural basins) were monitored.
Results: The existence of allometricrelations in drainage basins that are progressing toward the equilibrium (natural basins and basins affected by erosion) are significant and verifiable.This kind of relations do not exist in tectonic affected basins that were moving away from the equilibrium.
Conclusions:Allometric relations in drainage basins can define different states of system such as equilibrium. Moreover, any factor that causes the basin to move away from equilibrium needs to have an initial effect on basin relations to cause disorder in the system,and this change,in many cases,can be formulated or demonstrated by allometric model. Therefore the allometric equations could be considered an important tool in predicting the evolution of drainage basins and assessing their performance in the past and present.  

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The present study was conducted in Electric Blue Cichlid Sciaenochromis fryeri in early larval developmental stages from the fifth day post hatching (DPH) until 51 DPH to determine day of transforming from embryo to juvenile. Morphological characteristics were evaluated by using ImageJ software. Allometric growth patterns were calculated based on the formula Y=aX^b. Yolk sac depletion was occurred on day 9. Scales were developed on day 19 and finaly developed juvenile shape. allometric pattern of different body segments were calculated according to isometry, positive, and negative allometry. Positive allometry of head and tail prior to inflexion point and variation in allometric growth pattern in different body segment determine priorities of organogenesis for survival in fish early life history. The obtained results showed consistency between the larval morphological changes and development of organs related to sensory movements and larval behavior. Every morphological change in larvae displays the development and evolution of one of the organs involved in feeding, breathing, swimming and sensory organs.