Bioindicators at different levels of biological organization
Biological responses towards environmental stress could be induced at molecular, cellular, tissue, biochemical, physiological, behavioral, genetic, and even population and community levels. Environmental stresses could change enzyme levels or cellular activities. Such changes can induce behavioral, structural or functional responses (e.g. hormonal regulation, metabolism and immune responses), and may eventually alter the individual organism’s ability to grow, reproduce or survive. These changes could act as an indication on the status of our biological community, allowing us to predict if a particular group of organisms or the biological community as a whole is healthy or stressed.
In general, molecular, biochemical and physiological responses are more specific and sensitive to a particular environmental stress, while population and community responses are indicative of the general ecosystem health.