CONSERVATION OF MASS AND ENERGY (BIOLOGICAL SYSTEMS)
Living systems obey physical conservation laws; energy and matter must be obtained from the environment.

THERMODYNAMIC DEPENDENCE
Organisms must increase total entropy; local order requires external energy input.

CARRYING CAPACITY
Population size is limited by available resources and environmental constraints.

FINITE LIFESPAN
All organisms experience biological aging and eventual death.

METABOLIC RATE CONSTRAINT (ALLOMETRIC SCALING)
Metabolic rate scales with body mass (approximately to the 3/4 power).

GENETIC FIDELITY LIMIT
DNA replication has a non-zero error rate; mutation cannot be eliminated.

SELECTION CONSTRAINT
Evolution operates only on existing variation; it cannot select traits that do not arise.

TRADE-OFF CONSTRAINT
Biological systems face resource allocation trade-offs (e.g., growth vs reproduction vs maintenance).

REPRODUCTIVE RATE LIMIT
Reproduction is bounded by gestation time, developmental time, and physiological capacity.

DIFFUSION LIMIT
Transport of molecules within cells and tissues is constrained by diffusion rates and surface-area-to-volume ratios.

OXYGEN AND NUTRIENT DEPENDENCE
Multicellular life requires continuous resource input; deprivation leads to system failure.

ECOLOGICAL INTERDEPENDENCE
Species survival depends on ecosystem stability and trophic relationships.