In addition, different species can differ in the width of the range for some factor that they can tolerate. Now let's consider different ways in which animals deal physiologically with abiotic factors. One important distinction is between conformers , which allow their body conditions to change with environmental conditions, and regulators , which maintain constant body conditions over different environmental conditions. Consider costs and benefits to these two strategies. If body conditions are allowed to change, under some conditions enzymes will not be functioning optimally.
Regulators maintain constant conditions, which maintain high enzyme function.
The following graph shows regulation in three species of amphipod. Note that if they were conforming, values would fall along the straight line with slope 1 that runs through the graph. The amphipod body salinities do not fall on this line for the most part, so they are regulating. Note that when environmental salinity reaches the line, they do conform some. Many animals regulate over some range of conditions but may conform for extreme conditions.