Developmental Mechanisms of Evolutionary Change Course

Lesson 1 • Core Concepts and Terminology

Defines homology, analogy, pleiotropy, and modularity as used in developmental evolution. Precise terminology prevents conceptual errors throughout the course.

Lesson 2 • History and Scope of Evo-Devo

Traces the field from classical embryology through the modern synthesis to evo-devo. Provides historical context that anchors all subsequent mechanistic concepts.

Lesson 3 • Genotype-Phenotype Mapping

Explains how genetic variation translates into morphological outcomes via developmental processes. Connects molecular genetics to macroscopic evolutionary change.

Lesson 1 • Transcription Factor Networks

Analyzes gene regulatory networks (GRNs) built from transcription factors that control cell fate. Demonstrates how network topology constrains and enables evolutionary change.

Lesson 2 • Toolkit Gene Conservation Across Phyla

Compares toolkit gene usage in vertebrates, insects, and echinoderms to reveal deep homology. Reinforces the concept that morphological diversity arises from regulatory, not structural, gene change.

Lesson 3 • Signaling Pathways in Patterning

Examines Wnt, Hedgehog, Notch, and BMP pathways as reused developmental signals. Shows how pathway redeployment underlies morphological novelty.

Lesson 4 • Hox Genes and Axial Patterning

Covers Hox gene organization, collinearity, and roles in anterior-posterior axis specification. Establishes the paradigm of conserved developmental regulators driving body plan diversity.

Lesson 1 • Detecting Regulatory Changes in Genomes

Introduces comparative genomics, ATAC-seq, and ChIP-seq approaches for identifying functional regulatory elements. Equips students to evaluate empirical evidence for cis-regulatory evolution.

Lesson 2 • Pleiotropy, Modularity, and Evolvability

Connects modular enhancer architecture to reduced pleiotropy and increased evolvability. Shows how regulatory modularity allows trait-specific evolution without systemic disruption.

Lesson 3 • Case Studies in Regulatory Evolution

Examines pigmentation, limb, and skeletal evolution as documented cis-regulatory case studies. Grounds abstract principles in empirically validated examples students can reference.

Lesson 1 • Types of Developmental Constraints

Classifies physical, genetic, and epigenetic constraints that restrict phenotypic variation. Establishes a taxonomy students apply when analyzing evolutionary patterns.

Lesson 2 • Canalization and Genetic Assimilation

Covers Waddington's canalization model and the mechanism of genetic assimilation of plastic responses. Links developmental buffering to evolutionary innovation under environmental stress.

Lesson 3 • Developmental Bias and Variation

Explains how developmental processes generate non-random phenotypic variation, biasing evolution. Distinguishes developmental bias from natural selection as an evolutionary force.

Lesson 4 • Phylogenetic Patterns of Constraint

Uses comparative phylogenetic methods to detect constraint signatures in morphological data. Connects developmental mechanism to macroevolutionary pattern analysis.

Lesson 1 • Allometry and Growth Scaling

Covers isometric and allometric growth, scaling laws, and their developmental bases. Connects growth regulation to the evolution of body proportions and organ size.

Lesson 2 • Heterochrony: Concepts and Classification

Defines heterochrony and presents the clock-and-offset model with paedomorphosis and peramorphosis categories. Provides the analytical framework for timing-based evolutionary comparisons.

Lesson 3 • Life History Evolution and Development

Links developmental timing changes to life history trade-offs including maturation rate and reproductive timing. Integrates ecological context into developmental evolutionary analysis.

Lesson 4 • Heterotopy and Spatial Redeployment

Defines heterotopy as spatial shifts in developmental process location and distinguishes it from heterochrony. Illustrates how ectopic expression drives morphological novelty.

Lesson 1 • Epigenetic Mechanisms in Development

Covers DNA methylation, histone modification, and chromatin remodeling as developmental regulators. Establishes the molecular toolkit for understanding epigenetic contributions to evolution.

Lesson 2 • Niche Construction and Developmental Feedback

Introduces niche construction theory and how organisms modify environments that feed back on development. Connects developmental plasticity to eco-evolutionary dynamics.

Lesson 3 • Phenotypic Plasticity Mechanisms

Analyzes reaction norms, developmental switches, and polyphenism as forms of adaptive plasticity. Shows how plasticity can precede and facilitate genetic evolutionary change.

Lesson 1 • Co-option and Developmental Repurposing

Examines how existing developmental programs are recruited to build new structures. Provides a mechanistic alternative to de novo origin for most evolutionary novelties.

Lesson 2 • Gene Duplication and Subfunctionalization

Covers paralog evolution through neofunctionalization, subfunctionalization, and dosage models. Explains how gene family expansion generates raw material for developmental innovation.

Lesson 3 • Body Plan Origins and Cambrian Explosion

Evaluates developmental hypotheses for the rapid diversification of animal body plans. Integrates fossil, genomic, and developmental data to assess competing explanations.

Lesson 4 • Origin of New Cell Types

Analyzes transcription factor combinations and GRN rewiring that produce novel cell identities. Connects cell type evolution to organ and body plan innovation.

Lesson 1 • Modern Synthesis and Its Limits

Reviews the Modern Synthesis assumptions and identifies phenomena it inadequately explains. Sets the stage for understanding why an extended framework is needed.

Lesson 2 • Current Debates and Future Directions

Surveys active controversies including the scope of EES, the role of drift, and the status of developmental constraints. Prepares students to engage with primary literature critically.

Lesson 3 • Macroevolution Through a Developmental Lens

Applies developmental mechanisms to explain macroevolutionary patterns including stasis, disparity, and key innovations. Bridges micro- and macroevolutionary scales using developmental data.

Lesson 4 • Integrating Ecology and Development

Examines eco-evo-devo as the integration of ecological context into developmental evolutionary analysis. Shows how environmental signals shape developmental programs and evolutionary trajectories.