Original figure description: This photograph shows a newborn baby.
A single fertilized egg develops over the span of nine months into an infant consisting of trillions of cells and capable of surviving outside the womb. (credit: “Seattleye”/flickr.com)
In approximately nine months, a single cell—a fertilized egg—develops into a fully formed infant consisting of trillions of cells with myriad specialized functions. The dramatic changes of fertilization, embryonic development, and fetal development are followed by remarkable adaptations of the newborn to life outside the womb. An offspring’s normal development depends upon the appropriate synthesis of structural and functional proteins. This, in turn, is governed by the genetic material inherited from the egg and sperm, as well as environmental factors.
Attribution. Anatomy and Physiology 2e, OpenStax, Rice University, and the original contributing authors credited in the preface. Licensed under Creative Commons Attribution 4.0 International. CC BY 4.0. Original book at OpenStax ↗. EvidenceHelix text edition adapted from the pinned OpenStax source: CNXML converted to HTML; original prose, learning objectives, tables, exercises, glossary and captions retained. Images are not reproduced; external figure links and descriptions replace them. This is not the original full illustrated edition. No new scientific content was added. Source edition content may differ from current OpenStax revisions.