Groups A-C are physiologically similar; S. sonnei (group D) can be differentiated on the basis of biochemical metabolism assays.

C. milleri and C. holmii are physiologically similar, but DNA testing established them as distinct.

The most primitive order of flying insects, the mayflies (Ephemeroptera), are also those who are most morphologically and physiologically similar to these wingless insects.

The EC value is useful for comparing the potency of drugs with similar efficacies producing physiologically similar effects.

The team concluded that running on the blades appears to be physiologically similar but mechanically different from running with biological legs.

They have a four-chambered heart, although modified for their ectothermic nature due to an elongated cardiac septum, physiologically similar to the heart of a bird, which is especially efficient at oxygenating their blood.

The elephantine Ytram was in some ways physiologically similar to Brist in that he had extensive control of certain internal body fluid systems.

The authors found a surprising amount of correlated adaptation to "moderate" temperatures surrounding 37 C, suggesting that selection at this temperature had favored mutations that also improved performance at (presumably) physiologically similar temperatures.

The Thermoanaerobacteriales as previously mentioned are polyphyletic, and consists of over six morphologically and physiologically similar clades:

It is physiologically similar to some species of the genus, particularly the magnificent tree frog (L. splendida) and the giant tree frog (L. infrafrenata).