Adaptability and Adaptive Potential: A Law of Living Systems

Introduction

Adaptability is one of the most widely shared principles of life: organisms persist because they can maintain their functions despite variations in their environment, or modify them when those variations require it. Life, after all, unfolds under changing conditions. Temperature, resource availability, mechanical loads, interactions with other organisms, and reproductive conditions all vary over time.

This general capacity is thus often referred to as adaptability. However, the word covers several distinct phenomena. For example, a cell can change its metabolism within minutes, an organism can adjust its physiology over its lifetime, a population can evolve over generations, and an ecosystem can reorganize after a disturbance. These processes are certainly linked by the same question — how can a system maintain some functionality in the face of change? — but they do not rely on the same mechanisms.

Adaptability, Adaptation, and Plasticity

It is also important to distinguish adaptability from adaptation. First, adaptability refers to a capacity or a functional property. By contrast, adaptation, in its evolutionary sense, refers to the outcome of heritable changes selected within a population. Plasticity, for its part, allows an individual to change its phenotype during its lifetime without requiring a genetic change [2, 4].

Five Concepts Not to Confuse

Five concepts, often confused, structure this entire article:

However, plasticity and robustness are not simply opposites. Indeed, an organism can change some characteristics while keeping other functions stable. Research on biological robustness also shows that robustness, plasticity, and evolvability can sometimes reinforce one another [1–3].

Purpose of This Article

The purpose of this article is to offer an integrated view of adaptability across several levels of organization, from molecular networks to ecosystems, and then to show how this view sheds light on a specific case: the human body in a seated position. Here, the term “adaptive potential” refers to a system’s latent capacity to produce different responses, maintain its functions, or generate new solutions when faced with a disturbance. For the seated body, the SBNFA™ framework distinguishes two expressions of it — postural adaptability and tissue adaptability — presented in section 8.

1. Defining Adaptability

Before discussing potential, we need to clarify what adaptability is — and what it is not.

A Functional Property, Not a Single Mechanism

Indeed, adaptability is not a single mechanism. Rather, it results from the interaction of several properties: plasticity, robustness, redundancy, modularity, repair capacity, memory, learning, and genetic variability.

Thus, an adaptable system can respond in several ways. It can change how it functions, maintain its configuration despite the disturbance, activate an alternative pathway, or change state when conditions become incompatible with its original organization.

This diversity therefore explains why it is difficult to give a single definition of adaptability. In evolutionary biology, it may be associated with a population’s capacity to produce variants and respond to selection. In physiology, it refers more to an organism’s regulation and plasticity. In ecology, it concerns the capacity of a population or ecosystem to absorb a disturbance and reorganize.

Adaptation, Plasticity, and Acclimatization

Natural selection acts on heritable variation between individuals. It can favor certain traits when they increase survival or reproductive success in a given environment. In this framework, adaptation is therefore a property of populations, not an intentional transformation of an individual over its lifetime [6–8].

Phenotypic plasticity is the capacity of a single genotype to produce different characteristics depending on environmental conditions. This plasticity can involve morphology, physiology, development, or behavior, among others [2, 4, 5].

Acclimatization refers more specifically to a reversible adjustment in an individual exposed to natural or experimental conditions. Increased ventilatory capacity during exposure to altitude, seasonal changes in metabolism, and certain changes in thermal tolerance are general examples.

This distinction is essential to avoid attributing to evolution changes that actually stem from plasticity or physiological regulation.

2. Adaptive Potential

Adaptive potential does not refer to a single measurable reserve. Rather, it can be defined as the full set of options a system has for producing a functional response when subjected to a variation or disturbance.

This potential depends in particular on the diversity of accessible states, the redundancy of functions, the modularity of the organization, and the capacity to generate variation without immediately losing the main function. It is latent: it exists before the disturbance, regardless of how it will be used, and this is what distinguishes it from adaptability itself, which is a capacity expressed in a given situation.

Robustness and Plasticity

Robustness is the capacity of a trait or function to remain relatively stable despite a genetic or environmental disturbance. Plasticity, by contrast, is the capacity to change the phenotype according to conditions [1, 2].

These two properties may seem opposed. Yet an organism can be robust for some functions and plastic for others. It can thus maintain a relatively stable internal temperature while changing its behavior, metabolism, or blood circulation.

Theoretical and experimental work also suggests that robustness can promote evolvability. By tolerating certain genetic variations without losing its function, a system can accumulate a diversity of configurations and later produce phenotypic innovations under certain conditions [1, 3, 11].

Redundancy and Modularity

Redundancy first refers to the presence of several elements that can contribute to the same function. It can thus provide compensatory capacity when one element is impaired. Modularity, for its part, makes it possible to confine the effects of a disturbance to one part of the system.

These concepts are particularly important in biological networks. For example, a metabolic or regulatory network can sometimes use several pathways to reach a comparable result. This organization does not eliminate the limits of adaptation, but it can increase the number of available responses [3].

Nevertheless, redundancy should not be presented as an absolute advantage. It can carry an energy cost, produce complex interactions, or become useless if several elements are affected by the same disturbance.

3. Biological Mechanisms

Adaptability draws on several families of mechanisms, which operate on different time scales and combine in most real-life situations.

Phenotypic Plasticity

Phenotypic plasticity allows a single genotype to produce different phenotypes depending on the environment. It can appear during development, for example, or result from a reversible change in physiological activity [4, 5].

For example, in plants, light availability can change leaf shape, resource allocation, or stem growth. Similarly, in animals, temperature, nutrition, population density, or social interactions can influence growth, morphology, or behavior.

However, plasticity is not always beneficial. A response can be incomplete, too slow, energetically costly, or ill-suited when the environment changes faster than the capacity for regulation. Plasticity should therefore be understood as a possible response, not as a guarantee of successful adaptation [4].

Gene and Epigenetic Regulation

Cells adapt their activity by modulating the expression of their genes. This regulation depends in particular on internal and external signals, transcription factors, chromatin organization, and signaling networks. The classic example is the lactose operon in the bacterium Escherichia coli: the genes needed to use lactose are expressed only when this sugar is available [21].

The term “epigenetics” was introduced by Conrad Waddington to describe the interactions between development, the genome, and the environment that lead to the expression of the phenotype. His concept of the epigenetic landscape thus illustrated how developmental trajectories can be stabilized or modified [9].

In contemporary biology, epigenetics refers in particular to mechanisms such as DNA methylation, histone modifications, and certain chromatin regulation processes. These mechanisms can contribute to cellular plasticity, but we should avoid concluding that individual experiences are systematically passed on to offspring.

Indeed, the reversibility of certain epigenetic marks and their possible transmission depend on the mechanism, the tissue, the species, and the context. Epigenetics therefore does not constitute general proof of the inheritance of acquired characteristics; the extent of epigenetic inheritance remains a matter of debate [10].

Genetic Variation and Evolvability

Evolutionary adaptation relies on the existence of heritable variation and on differences in reproduction among individuals in a population. Mutation, recombination, gene flow, and drift also contribute to the structure of this variation [6, 7].

Natural selection therefore does not directly produce a response because an organism needs it. Rather, it changes the frequency of variants that are already present or that arise through mutation and recombination. The direction of evolution thus depends on the available variation, the environment, and the population’s history [8].

Finally, evolvability refers to a system’s capacity to produce heritable variation that can lead to adaptation. It depends in particular on genome organization, developmental networks, the robustness of phenotypes, and the way genetic variations are translated into observable traits [1, 3, 11].

Behavior, Learning, and Memory

Behavior offers a fast route to adaptation, because it can change the interaction with the environment without waiting for a morphological or genetic transformation. Learning, in particular, makes it possible to select responses based on their consequences.

However, it is better not to reduce learning to operant conditioning theory alone. Adaptive behaviors also draw on memory, exploration, imitation, anticipation, and decision-making. In many species, behavioral flexibility thus makes it possible to exploit new resources or avoid risks [13, 14].

As early as the late 19th century, Baldwin proposed that learning and behavior could influence the evolutionary trajectory of a lineage — an idea since known as the Baldwin effect [12].

This flexibility, however, comes at a cost. It requires time, cognitive capacity, reliable information, and sometimes a long learning period. A behavior can also be adaptive in one environment and harmful in another.

4. From Organism to Ecosystem

The mechanisms above come together at the level of populations, then ecosystems, where adaptability takes collective forms.

Adaptation of Populations

At the population level, adaptation therefore results from changes in the frequency of heritable variants. Natural selection can favor certain traits, while genetic drift changes frequencies randomly, especially in small populations. Finally, gene flow introduces or redistributes variants between populations [6, 7].

Two examples illustrate how fast these processes can be. First, in experimental evolution studies on Escherichia coli populations over 10,000 generations, the lineages increased their fitness in a constant environment while diversifying [22]. Second, in disease-carrying mosquitoes, insecticide resistance emerged under strong selection pressure [15].

These mechanisms do not always produce better adaptation, however. A population can lose diversity through drift, suffer inbreeding depression, or receive variants poorly suited to its local environment.

A population’s adaptability therefore depends on its genetic diversity, effective size, reproductive rate, habitat structure, and the speed of environmental change.

Ecosystem Resilience

At the ecosystem level, resilience generally refers to the capacity to absorb a disturbance and retain part of its functioning, or to reorganize after a major change. Holling distinguished stability around an equilibrium state from resilience, which concerns the persistence of functional organization despite a disturbance [17]. This approach was later extended to social-ecological systems, where adaptive capacity plays a central role [18].

A resilient ecosystem therefore does not necessarily return to its initial state. Instead, it can adopt a new configuration, with other dominant species, other flows of matter, and other relationships between organisms.

Diversity, functional redundancy, connectivity, and the presence of several energy transfer pathways can also contribute to resilience. However, they do not guarantee recovery when the disturbance exceeds a critical threshold.

Climate Change and the Limits of Adaptation

In the face of climate change, organisms and populations can thus change their distribution, behavior, physiology, or breeding calendar. For example, some species move toward more favorable areas; others adjust their flowering, breeding, or activity periods. The migration of monarch butterflies, which relies on complex sensory and physiological mechanisms, thus illustrates the scale of such seasonal responses [16].

Yet these responses are limited by the speed of change, habitat fragmentation, the availability of ecological corridors, interactions between species, and physiological limits. The Intergovernmental Panel on Climate Change (IPCC) emphasizes that adaptation options decrease as climate risks increase and ecological thresholds are crossed [19].

Coral bleaching illustrates this limit in particular. A rise in temperature can trigger a physiological response, but prolonged or overly intense exposure can exceed the compensatory capacities of the organism and its associated ecosystem [20].

5. Adaptability as a Cross-Cutting Property

Adaptability appears at different levels, but it does not work through the same mechanisms everywhere.

Comparisons between these levels should therefore remain cautious. A cell does not “adapt” in the same way as a population. A population does not learn in the individual sense, and an ecosystem does not necessarily have an intention or a purpose.

Rather, the common thread is the capacity to change a state, maintain a function, or explore another organization when conditions change. It is in this sense, and in this sense only, that adaptability can be called a general principle of life.

6. The Limits and Costs of Adaptability

Every adaptation has limits. An adaptive response can require energy, reduce another function, or become ineffective when the disturbance exceeds a certain threshold.

Life-history theories have thus shown that organisms must make trade-offs between growth, survival, and reproduction. Investing in defense, repair, or stress tolerance, for example, can reduce the resources available for other functions [23].

These trade-offs therefore explain why an organism cannot maximize all its capacities at once. A plant that invests more in defense may grow more slowly. Similarly, an animal that maintains a high level of vigilance may reduce its feeding or reproduction. A population that adapts quickly to one condition may become more vulnerable when the environment changes again.

7. A Look Toward Artificial Systems

Artificial systems draw on several properties of living systems: learning, selection, real-time adaptation, modularity, and fault tolerance. Evolutionary algorithms and neural networks, in particular, use certain analogies with selection, learning, and biological networks [24].

However, these analogies remain partial. An algorithm does not necessarily have a metabolism, biological reproduction, or physiological self-regulation. It is better to speak of formal inspiration rather than complete similarity with living systems.

The value of these comparisons lies in the search for systems capable of changing their behavior based on data, maintaining certain functions despite disturbances, and producing new solutions within a given space of constraints. The same logic of careful transposition guides the next section, devoted to the seated human body.

8. From Living Systems to Human Posture: The Four SBNFA™ Laws of Living Systems

Blue Portance’s SBNFA™ — Systemic Biological Neuro-fascial Adaptive Framework — applies the principle of adaptability to a specific case: the human body in a seated position. It does not claim to prove that adaptability is a “law” in the physical sense. Rather, it identifies four operating principles of living systems, called “laws of living systems,” and derives from them what a seat must allow the body to do [28].

The Four SBNFA™ Laws of Living Systems

From Variability to Natural Posture

Here we find, applied to sitting, the concepts from the previous sections. The first law extends the question of variability: Bernstein showed that movement coordination does not consist of repeating an identical gesture, but of solving a motor problem anew each time [25]. Research in neurologic physical therapy has also proposed that variability that is neither too low nor excessive characterizes a healthy system, while variability that is too reduced or disordered would be associated with a lower capacity for adaptation [26]. This hypothesis concerns movement in general: it has not been established specifically for sitting.

Human rest, moreover, is not synonymous with immobility: among the Hadza of Tanzania, adults spend a notable share of their non-ambulatory rest time squatting, a posture in which muscle activity remains higher than that observed in a chair [27]. The framework thus defines a natural posture as a configuration in which the body retains a capacity for adjustment, load redistribution, and active regulation [28].

Adaptability and Adaptive Potential While Sitting

Transposed to the seated human, the “adaptive potential” of section 2 — the space of responses that can still be mobilized — takes a precise form. The Blue Portance glossary distinguishes three related concepts:

In this reading, adaptive potential therefore results from the interaction between the person, the task, and the environment, which includes the seat. It is analyzed in particular through freedom of movement, dynamic stability, the capacity to adjust and redistribute loads, and variation in points of support [28]. The “accessible states” of biology thus become, here, the stabilizable balance configurations and the degrees of freedom that can actually be used.

Postural Adaptability, Tissue Adaptability, and the Sensory Loop

In the framework, adaptability is the integrating concept: the body’s capacity to adjust its postural organization and tissue responses in the face of loads, while preserving balance, mobility, and load distribution. It has two expressions to distinguish: postural adaptability, the adjustment of the body’s organization, and tissue adaptability, the response of tissues to mechanical loading. Immediate postural adjustment and longer-term tissue adaptation should not be confused [28].

A sensory, informational, and proprioceptive loop contributes to the process that enables adaptation: body movement, mechanical information transmitted to the seat, the seat’s response, sensory feedback to the body, sensorimotor adjustment. The seat does not produce proprioception: it handles the mechanical information the body gives it, including micro-movements, and may or may not respond to it without delay. This dimension is therefore not a third adaptability: it is a cross-cutting mechanism of adjustment, which the fourth law of living systems — autonomous regulation — sums up as follows: the body constantly adjusts its posture based on sensory feedback [28].

Three Cross-Cutting Dimensions of Analysis

Three dimensions of analysis make it possible to read the framework’s seven functions without replacing or redistributing them: the postural or biomechanical dimension (body organization, degrees of freedom, accessible balance states), the sensory, informational, and proprioceptive dimension, and the tissue dimension (loads, variation and redistribution, tissue responses). A single function can involve several of them: the first cuts across all three, since adaptive potential concerns postural organization, balance, and the variation of loads on the tissues alike.

These levels of analysis do not add, remove, or redistribute any function or variable, and they are not scored: they serve as an explanatory grid for the framework.

9. How Aporia® Makes Adaptive Potential Possible While Sitting

In the SBNFA™, the first of the seven functions evaluated is “preservation of the subject’s adaptive potential.” It rests on a simple idea: the subject must remain the initiator of change, with the seat responding to their mechanical demand without imposing its own trajectory [28]. This function is cross-cutting: adaptive potential concerns postural organization, balance, and the variation of loads on the tissues alike.

First Function: Two Variables

Two variables are distinguished. The first concerns the governance of movement: who initiates it, chooses its direction, and controls its amplitude, speed, and stopping point. The second, for its part, concerns the mechanical resolution of the interface: does it respond to very small adjustments, without an excessive threshold, dead zone, notch, or dominant return force? [28]

The Aporia® ExoBase Architecture

The Aporia® ExoBase thus combines a curved, mobile base with four articulated, mechanically independent pads, each with its own foam and its own cover. The framework also describes a continuous space of balanced oscillations up to ±45°, within which the person can move from one stabilized position to another without having to maintain an imbalance imposed by the seat [29, 30]. It is in this sense that Aporia® makes adaptive potential possible while sitting: not by setting the posture on the subject’s behalf, but by opposing them with no threshold, no notch, and no imposed zero point.

What the Evaluation Shows

Limitations and Upcoming Measurements

However, this evaluation is expert-based, not instrumented: it covers the capacities offered by the architecture, not how a given person uses them, and it concerns a prototype that is not yet commercially available. The framework also documents limitations: horizontal displacements and spine–pelvis pivoting are bounded by the geometry of the assembly, pressure distribution depends on body type, and firmness cannot be adjusted separately on each pad [29, 30]. In addition, instrumented measurements are scheduled with the GIBOC laboratory of the Institute of Movement Sciences in the first half of 2027.

The full benchmark is presented in the article Boréal–Aporia vs. Dynamic Seats.

10. Conclusion

Adaptability is a cross-cutting property of living systems, but it is not a universal law in the sense of a single mechanism working identically at every level. Rather, it refers to a family of capacities that allow a system to maintain a function, change its state, or produce a new organization in the face of variation. It is as an organizing principle that it can be called a “law of living systems.”

In the organism, it relies first on physiological regulation, plasticity, behavior, and learning. In populations, it then depends on heritable variation and evolution. In ecosystems, finally, it takes the form of resistance, resilience, and reorganization.

Adaptive potential can then be understood as the combination of several properties: diversity of responses, robustness of functions, modularity of organization, repair capacity, and the ability to produce usable variation. This potential, however, is not unlimited. It depends on resources, the time available, the speed of change, and the system’s own thresholds.

From Principle to Seating

Applied to sitting, this principle therefore leads to one criterion: not “does the seat move?” but “what space of responses does it leave the body?” This criterion is read through two expressions of adaptability: postural, where the person reorganizes their posture, and tissue, where the weight-bearing tissues respond to loads. Aporia® is designed to meet this criterion; its effects, however, remain to be measured.