Final answer:
A biological rhythm that aligns with an environmental rhythm is termed 'entrained'. Environmental cues like light and temperature help synchronize these internal circadian rhythms with the world outside to coordinate physiological functions effectively.
Step-by-step explanation:
A biological rhythm that is synchronized with an environmental rhythm is said to be entrained. These rhythms, often circadian, align with the daily cycle of the environment, ensuring that an organism's internal processes are coordinated with the external world. For instance, human sleep-wake cycles, body temperature, blood pressure, and various other physiological processes exhibit circadian rhythmicity. The circadian clock, a structure located at the base of the brain, plays a crucial role in maintaining these rhythms, with environmental factors like light serving as important cues for entrainment.
Circadian rhythms are important for maintaining the timing and coordination of various physiological events, which involve the regulation of processes to ensure efficiency and balance in the body's systems. When these rhythms are entrained, organisms can optimize functions such as sleep, feeding, and hormone production corresponding to the appropriate time of day or night.
In contrast, endogenous rhythms are those that are generated within an organism without external cues, and free-running circadian rhythms occur in the absence of external time cues. A zeitgeber is an external cue like light or temperature that can synchronize internal clocks, while the term "phasing" refers to the alignment stage of a rhythm. However, the final answer to the question posed is that a biological rhythm brought into phase with an environmental rhythm is known as entrained.