| 1. Domain | 1.1 Scope of the Domain | Boundaries | The range of phenomena the science includes and excludes. | Focuses on evolutionary processes operating above the population level: speciation, extinction, diversification, macroevolutionary trends, adaptive radiations, long-term morphological change, and lineage-splitting dynamics. Includes mechanisms of species formation, tempo and mode of evolution, and large-scale biodiversity patterns. Excludes short-term microevolutionary allele-frequency shifts unless they scale up to macroevolutionary consequences. |
| | Scale | The spatial, temporal, or organizational level at which the science operates (e.g., quantum, cellular, social, cosmic). | Operates at species, clade, and higher taxonomic levels; temporal scales range from thousands to hundreds of millions of years; spatial scales span local radiations to global biogeographic patterns. |
| 1.2 Ontological Commitments | Entities | The kinds of things assumed to exist within the domain (particles, organisms, agents, fields, etc.). | Species, lineages, clades, reproductive barriers, geographic ranges, ecological niches, diversification events, extinction events, macroevolutionary trends, speciation modes, phylogenies. |
| | Properties | The fundamental attributes these entities possess (mass, charge, genotype, preference, etc.). | Speciation rate, extinction rate, diversification rate, morphological disparity, ecological opportunity, reproductive isolation strength, biogeographic range structure, tempo (gradual vs punctuated), mode (anagenesis vs cladogenesis). |
| | Categories | The basic ontological types used to classify domain elements (substances, processes, relations, structures). | Speciation types (allopatric, sympatric, parapatric, peripatric), isolation types (prezygotic, postzygotic), macroevolutionary models (adaptive radiation, stasis, gradualism, punctuated equilibrium), lineage categories (sister clades, stem vs crown groups). |
| 1.3 State-Variables | Variables | The measurable or definable properties that describe system conditions. | Speciation/extinction rates, lineage diversity, morphological disparity scores, range size, isolation-barrier strength, ecological niche metrics, diversification parameters (λ, μ), transition probabilities among speciation modes. |
| | Parameterization | How variables encode and represent the system’s state. | System encoded through branching-time distributions, diversification rate matrices, lineage-through-time plots, morphological or ecological trait distances, biogeographic ranges, and probabilistic speciation/extinction models (e.g., birth–death models). |
| 1.4 Admissible Idealizations | Simplifications | Conceptual reductions used to make the domain tractable (point masses, rational agents, perfect gases). | Treating species as discrete, non-overlapping units; assuming constant diversification rates; ignoring hybridization or reticulation; reducing speciation to binary splits; treating morphological change as uniform; assuming ecological niches are stable through time. |
| | Validity Conditions | The limits and contexts in which idealizations hold or break down. | Idealizations fail under variable diversification dynamics, reticulate evolution, hybrid speciation, rapid environmental turnover, incomplete lineage sorting, cryptic species diversity, or high morphological convergence. |
| 1.5 Domain Assumptions | Structural Assumptions | Background ontological stances such as determinism, continuity, randomness, discreteness. | Speciation and extinction shape long-term diversity; evolutionary lineages can be modeled as branching processes; reproductive isolation evolves through definable mechanisms; macroevolutionary patterns reflect accumulations of microevolutionary processes under broad-scale contingencies. |
| | Implicit Commitments | Unstated but necessary assumptions that shape the field’s conceptual structure. | Assumes species boundaries are definable, macroevolutionary signals are preserved in fossil/phylogenetic data, diversification parameters are estimable, and long-term trends are not overwhelmed by noise or data incompleteness. |
| 1.6 Internal Coherence Requirements | Consistency | The demand that domain concepts do not contradict one another. | Speciation mechanisms, diversification patterns, reproductive isolation concepts, and macroevolutionary models must not contradict one another; interpretations of clade histories must align with phylogenetic and fossil evidence. |
| | Compatibility | The requirement that entities, variables, and assumptions fit together into a unified descriptive framework. | Species concepts, reproductive-isolation theory, phylogenetic patterns, morphological trends, and diversification parameters must integrate into a unified framework explaining lineage splitting and large-scale evolutionary change. |
| 2. Evidence Layer | 2.1 Observable Phenomena | Observables | The aspects of the domain that can produce detectable signals accessible to measurement. | Fossil lineage splitting and extinction patterns, morphological transitions, biogeographic range shifts, diversification bursts or slowdowns, reproductive isolation markers, hybrid zones, sister-clade asymmetry, lineage-through-time curves, and trait divergence across species. |
| | Detection Limits | The boundaries of what can be resolved or sensed by current instruments or methods. | Limited by fossil incompleteness, temporal resolution of geologic strata, poor preservation of soft tissues, difficulty detecting cryptic species, uncertainty in divergence-time estimates, and limited power to detect rapid or ancient speciation events. |
| 2.2 Measurement Systems | Units | Standardized quantifications (meters, seconds, volts, decibels, dollars, etc.) necessary for consistent comparison. | Speciation/extinction rate parameters (λ, μ), divergence time (Mya), morphological disparity units, range size metrics, reproductive isolation indices, branch-length units, diversification-rate shifts, geographic distance measures. |
| | Instruments | Devices and tools (microscopes, spectrometers, sensors, surveys, detectors) used to produce measurements. | Fossil excavation and dating systems, stratigraphic tools, radiometric dating, phylogenetic software, biogeographic modeling platforms, morphological measurement systems, genomic sequencing for species delimitation, reproductive-isolation assays. |
| 2.3 Operational Definitions | Definitions | Terms defined by specific measurement procedures, ensuring empirical clarity. | Speciation defined by formation of independently evolving lineages; reproductive isolation defined by barriers preventing gene flow; diversification rate defined as λ–μ; morphological disparity defined as variance in multivariate trait space; species defined per chosen species concept. |
| | Procedures | The explicit steps required to perform a measurement in a reproducible way. | Fossil coding, stratigraphic correlation, divergence-time calibration, range mapping, lineage-through-time reconstruction, reproductive-barrier testing, phylogenetic inference, trait quantification, species-delimitation analysis. |
| 2.4 Data Acquisition | Protocols | Formal processes for gathering data under controlled or standardized conditions. | Standardized fossil-collection strategies, consistent morphological coding, validated molecular sampling for species boundaries, replicated measurements, stratigraphic context control, rigorous biogeographic sampling across ranges. |
| | Sampling | Rules determining which subset of the domain is measured and how representative it is. | Sampling across clades, geographic regions, and time intervals; avoiding geographic bias; including fossil and extant taxa; ensuring adequate representation of rapidly radiating groups; collecting multiple individuals per species when possible. |
| 2.5 Data Character & Format | Data Types | The form raw evidence takes (time series, spectra, images, counts, qualitative records). | Fossil occurrence datasets, morphological character matrices, divergence-time estimates, dated phylogenetic trees, lineage-through-time plots, species-distribution maps, reproductive isolation matrices, macroevolutionary rate tables. |
| | Resolution | The granularity or precision with which data is captured. | Determined by fossil preservation quality, dating precision, phylogenetic signal strength, sampling density across lineages, trait-measurement precision, and the temporal spacing of biogeographic or morphological data. |
| 2.6 Reliability & Calibration | Calibration | Adjustment procedures ensuring instruments produce accurate results. | Calibration of divergence times with fossil constraints, radiometric dating checks, phylogenetic model-fit evaluation, stratigraphic alignment, trait-measurement validation, cross-checking species boundaries with independent datasets. |
| | Error Characterization | Identification and quantification of noise, uncertainty, bias, and measurement error. | Identification of fossil misassignments, dating uncertainty, sampling bias, phylogenetic error, model misfit in diversification-rate estimation, incomplete species boundaries, biogeographic uncertainty, and quantification of random vs systematic error sources. |
| 3. Structural Layer | 3.1 Patterns & Regularities | Laws / Relations | Stable, repeatable patterns governing how observables behave across conditions. | Speciation and extinction follow measurable rate patterns; diversification dynamics produce predictable lineage-through-time curves; morphological evolution often shows bursts (rapid change) followed by stasis; geographic isolation consistently precedes many speciation events; adaptive radiations produce rapid early diversification followed by slowdowns. |
| | Invariants | Quantities or properties that remain constant under transformations (symmetries, conservation laws). | Monophyly as the fundamental grouping principle; consistent association between reproductive isolation and lineage independence; stable mathematical forms of birth–death diversification models; recurrent macroevolutionary patterns such as adaptive radiation, convergence, and stasis. |
| 3.2 Causal Architecture | Mechanisms | Underlying processes or structures that produce the observed regularities. | Geographic isolation creates reproductive barriers; ecological divergence drives niche specialization; genetic incompatibilities accumulate through drift and selection; environmental change triggers extinction or speciation pulses; key innovations enable new adaptive zones and diversification. |
| | Pathways | Organized sequences of interactions forming a causal chain or network. | Isolation → divergence → reproductive isolation → speciation; ecological opportunity → niche expansion → adaptive radiation; environmental disruption → diversification shift; mutation → incompatibility → hybrid dysfunction → lineage splitting. |
| 3.3 Theoretical Vocabulary | Concepts | Core terms that encode the domain’s structure (force, gene, equilibrium, field). | Speciation, extinction, diversification rate, reproductive isolation, adaptive radiation, key innovation, punctuated equilibrium, gradualism, stasis, morphological disparity, lineage-through-time curves, biogeographic structuring. |
| | Classifications | Taxonomies, categories, or typologies that organize entities and relations. | Speciation modes (allopatric, sympatric, parapatric, peripatric), isolation mechanisms (prezygotic, postzygotic), macroevolutionary models (gradualism, punctuated equilibrium, adaptive radiation), clade types (crown vs stem), diversification regimes (constant-rate vs variable-rate). |
| 3.4 Formal Representations | Equations | Mathematical constructs expressing laws, relations, or mechanisms. | Birth–death diversification equations (λ, μ), models for net diversification (r = λ − μ), macroevolutionary rate-shift models, trait-evolution models (Brownian motion, OU), probability models for speciation modes, biogeographic transition matrices. |
| | Models | Structured representations—mathematical, computational, or conceptual—used to predict and explain phenomena. | Birth–death models, state-dependent speciation/extinction (SSE) models, adaptive landscape models, morphological evolution models (BM, OU), geographic speciation models, punctuated-equilibrium models, multi-rate diversification models. |
| 3.5 Idealized Structures | Simplified Models | Purposeful abstractions that capture essential dynamics while omitting irrelevant detail. | Treating speciation as instantaneous; treating species as discrete non-overlapping units; assuming constant diversification rates; ignoring hybridization or reticulation; reducing complex ecological niches to single variables; modeling geographic ranges as static. |
| | Limit Conditions | Regimes where specific models or approximations hold (classical vs. quantum, linear vs. nonlinear). | Fail in systems with hybrid speciation, strong reticulation, rapid environmental turnover, cryptic species, highly variable mutation or extinction rates, underestimated fossil bias, or non-tree-like evolutionary histories. |
| 3.6 Integrative Frameworks | Unifying Theories | Higher-order structures that connect disparate laws or mechanisms under a coherent whole. | Macroevolution viewed as emergent from microevolutionary processes interacting with large-scale ecological and geological forces; speciation theory unifies reproductive isolation, ecological divergence, and geographic structure; diversification models connect speciation, extinction, and morphological evolution into a single evolutionary narrative. |
| | Interdisciplinary Links | Points where the theory connects to adjacent sciences or larger explanatory systems. | Connects to geology (stratigraphy, mass extinctions), ecology (niche dynamics, community structure), genetics (incompatibility accumulation), paleontology (fossil patterns), systematics (phylogenetic structure), and biogeography (range evolution). |
| 4. Method Layer | 4.1 Inquiry Design | Experimental Design | Structured plans for manipulating variables to test causal claims. | Manipulating ecological or geographic conditions in controlled systems (e.g., experimental islands, mesocosms), altering population structure, introducing or removing barriers, adjusting selection pressures, or simulating founder events to test causal hypotheses about speciation or diversification. |
| | Observational Design | Systematic approaches for gathering non-manipulated data (surveys, field studies, natural experiments). | Documenting natural speciation events, tracking diversification patterns across clades, observing hybrid zones, measuring geographic isolation in situ, analyzing morphological transitions, and studying natural radiations without intervention. |
| 4.2 Testing & Validation | Hypothesis Testing | Procedures for evaluating whether evidence supports or contradicts specific claims. | Testing alternative speciation modes (allopatric vs sympatric), comparing diversification models, testing rate shifts, validating reproductive isolation mechanisms, evaluating adaptive radiation hypotheses, and comparing predicted vs observed lineage-through-time patterns. |
| | Replication | The requirement that results be independently reproducible under similar conditions. | Repeating phylogenetic analyses, re-estimating diversification rates across different datasets, replicating species-delimitation analyses, reassessing barrier strength in multiple populations, and verifying morphological or ecological divergence with new samples. |
| 4.3 Inference & Evaluation | Statistical Inference | Rules for drawing conclusions from noisy or incomplete data. | Estimating speciation/extinction rates, inferring rate-shift locations, modeling trait evolution, quantifying reproductive isolation strength, estimating divergence times, and using likelihood/Bayesian methods to infer macroevolutionary processes. |
| | Model Comparison | Criteria (fit, simplicity, predictive accuracy, robustness) used to evaluate competing models. | Comparing constant-rate vs variable-rate diversification models, SSE models vs null models, geographic speciation models, trait-dependent diversification models, and competing biogeographic or morphological evolution models. |
| 4.4 Error Management | Error Analysis | Identification and quantification of random and systematic errors. | Identifying fossil incompleteness, dating uncertainty, phylogenetic error, model misfit, sampling bias in clade selection, misleading rate estimates from poor tree resolution, and quantifying random vs systematic error in diversification inference. |
| | Bias Control | Methods for minimizing subjective, instrumental, or procedural biases. | Improving taxon sampling, balancing fossil and extant representation, controlling for geographic bias, validating species boundaries, using multiple markers or trait datasets, and applying model-adequacy checks. |
| 4.5 Adjudication & Revision | Peer Scrutiny | Collective evaluation of claims through critique, review, and debate. | Reanalyzing diversification or speciation models, reviewing taxonomic assignments, comparing independent phylogenetic datasets, integrating fossil and molecular evidence, and revising interpretations when conflicts arise across lines of evidence. |
| | Theory Revision | Procedures for modifying, replacing, or discarding models based on new evidence. | Updating speciation mechanisms when new data indicate hybrid or reticulate origins, revising diversification-rate models when clade-specific dynamics differ, incorporating ecological or geological events into macroevolutionary theory when required. |
| 4.6 Integrity Conditions | Transparency | Requirements to disclose methods, data, assumptions, and limitations. | Full disclosure of fossil sampling procedures, dating methods, model assumptions, phylogenetic inference settings, diversification-model parameters, and sources of uncertainty; clear articulation of alternative evolutionary interpretations. |
| | Ethical Standards | Norms ensuring responsible conduct in experimentation, data handling, and publication. | Responsible handling of paleontological material, ethical collection of extant species, accurate reporting of phylogenetic and macroevolutionary results, proper attribution of datasets, and avoidance of selective reporting of diversification outcomes. |