Thoroughly updated, streamlined, and enhanced with pedagogical features, the twelfth edition of Barresi and Gilbert's Developmental Biology engages students and empowers instructors to effectively teach both the stable principles and the newest front-page research of this vast, complex, and multi-disciplinary field. This much loved, well-illustrated, and remarkably well written textbook invigorates the classical insights of embryology with cutting edge material, and makes the most complex topics understandable to a new generation of students. Designed with the undergraduate student in mind, this new, streamlined edition now contains studies of plant development, expanded coverage of regeneration, over a hundred new and revised illustrations, and deeply integrated active learning resources that build on the text's enthusiasm and accuracy. This is a text designed to make students become excited about how animals and plants develop their complex bodies from simple origins.

PART I: Patterns and Processes of Becoming: A Framework for Understanding Animal Development
1: The Making of a Body and a Field: Introduction to Developmental Biology
2: Specifying Identity: Mechanisms of Developmental Patterning
3: Differential Gene Expression: Mechanisms of Cell Differentiation
4: Cell-to-Cell Communication: Mechanisms of Morphogenesis

PART II: Gametogenesis and Fertilization: The Circle of Sex
5: Stem Cells: Their Potential and Their Niches
6: Sex Determination and Gametogenesis
7: Fertilization Beginning a New Organism

PART III: Early Development: Cleavage, Gastrulation, and Axis Formation
8: Snails, Flowers, and Nematodes: Different Mechanisms for Similar Patterns of Specification
9: The Genetics of Axis Specification in Drosophila
10: Sea Urchins and Tunicates: Deuterostome Invertebrates
11: Amphibians and Fish
12: Birds and Mammals

PART IV: Building with Ectoderm: The Vertebrate Nervous Systyem and Epidermis
13: Neural Tube Formation and Patterning
14: Brain Growth
15: Neural Crest Cells and Axonal Specificity
16: Ectodermal Placodes and the Epidermis

PART V: Building with Mesoderm and Endoderm: Organogenesis
17: Paraxial Mesoderm: The Somites and Their Derivatives
18: Intermediate and Lateral Plate Mesoderm: Heart, Blood, and Kidneys
19: Development of the Tetrapod Limb
20: The Endoderm: Tubes and Organs for Digestion and Respiration

PART VI: Postembryonic Development
21: Metamorphosis: The Hormonal Reactivation of Development
22: Regeneration: The Development of Rebuilding
23: Development in Health and Disease: Birth Defects, Endocrine Disruptors, and Cancer

PART VII: Development in Wider Contexts
24: Development and the Environment: Biotic, Abiotic, and Symbiotic Regulation of Development
25: Development and Evolution: Developmental Mechanisms of Evolutionary Change