Encyclopedia/1. The Cosmos & The Natural World/5. Life Sciences/05. Organismal Biology • Curated by Admin Timeline.sg
Endocrinology · Neuroethology
Chronological Storyline (30 Milestones)
1600 BCE
Edwin Smith Papyrus describes anatomy
An ancient Egyptian surgical papyrus contains systematic observations of the heart, vessels, and brain injuries, representing one of the earliest documented efforts to link organ structure to function. Source — Wikipedia:
The Edwin Smith papyrus, the world's oldest surviving surgical document. Written in hieratic script in ancient Egypt around 1600 B.C., the text describes anatomical observations and the examination, diagnosis, treatment, and prognosis of 48 types of medical problems in exquisite detail. Among the treatments described are closing wounds with sutures, preventing and curing infection with honey and moldy bread, stopping bleeding with raw meat, and immobilization of head and spinal cord injuries. Translated in 1930, the document reveals the sophistication and practicality of ancient Egyptian medicine. Recto Column 6 (right) and 7 (left) of the papyrus, pictured here, discuss facial trauma. (Cases 12-20) By Jeff Dahl - Edited version of Image:EdSmPaPlateVIandVIIPrintsx.jpg, Public domain, https://commons.wikimedia.org/w/index.php?curid=2854143
400 BCE
Hippocratic Corpus links body and environment
Greek medical texts attributed to the Hippocratic school proposed that health reflects a balance of four humors, an early framework for relating physiological function to diet, climate, and lifestyle. Source — Wikipedia:
Bust of Hippocrates By Unidentified engraver - 1881 Young Persons' Cyclopedia of Persons and Places Upload by RedWolf 05:45, Jan 10, 2005 (UTC), Public domain, https://commons.wikimedia.org/w/index.php?curid=164808
300 BCE
Charaka Samhita codifies Indian medicine
This foundational Ayurvedic text described digestion, metabolism, fetal development, and disease classification, establishing a systematic physiological framework that influenced South Asian medicine for centuries. Source — Wikipedia:
A section of the Carakasamhita - sutrasthana (Charaka) Asian Collection By Unknown author - https://wellcomeimages.org/indexplus/obf_images/ea/3a/3951eb729fdec6d8916e8d8be07e.jpg Gallery: https://wellcomeimages.org/indexplus/image/L0040423.html Wellcome Collection gallery (2018-03-22): https://wellcomecollection.org/works/f2kqft8j CC-BY-4.0, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=36096211
300 BCE
Huangdi Neijing systematizes Chinese medicine
The foundational text of Chinese medicine described circulation of qi and blood, organ networks, and pulse diagnosis, embedding physiological reasoning that influenced East Asian science for two millennia. Source — Wikipedia:
Huangdi Neijing (黄帝内経, kōteidaikei), Myōdō (明堂) By Unknown author - [1], Public domain, https://commons.wikimedia.org/w/index.php?curid=11662446
280 BCE
Herophilus and Erasistratus dissect living bodies
In Hellenistic Alexandria, these physicians conducted systematic dissection and possibly vivisection, distinguishing nerves from blood vessels and identifying the brain as the seat of intelligence. Source — Wikipedia:
Zaragoza - Antigua Facultad de Medicina - Medallón - Herófilo By Ecelan - Own work, CC BY-SA 3.0 es, https://commons.wikimedia.org/w/index.php?curid=16641053
250 BCE
Erasistratus reasons about organ function
Erasistratus of Ceos described heart valves and proposed that nerves carry 'pneuma' rather than blood, making early inferences about the functional specialization of organs. Source — Wikipedia:
Erasistratus reasons about organ function By Didier Descouens - Own work, Public domain, https://commons.wikimedia.org/w/index.php?curid=90209212
200 BCE
Sushruta Samhita details surgery and physiology
The Sushruta Samhita described surgical techniques, the pulse, wound healing, and the concept of bodily channels (srotas), representing an early Indian contribution to understanding organ function. Source — Wikipedia:
Nepal, Text- 12th-13th century; Images- 18th-19th century Books Ink and opaque watercolor on palm leaf Gift of Emeritus Professor and Mrs. Thomas O. Ballinger (M.87.271a-g) South and Southeast Asian Art By Unknown author - Image: http://collections.lacma.org/sites/default/files/remote_images/piction/ma-31972784-O3.jpg Gallery: http://collections.lacma.org/node/170472 archive copy at the Wayback Machine, Public domain, https://commons.wikimedia.org/w/index.php?curid=32452002
180 CE
Galen's physiological system dominates medicine
Claudius Galen conducted animal experiments and proposed that the liver produces blood, the heart vital spirits, and the brain animal spirits, creating a physiological framework that lasted over 1,300 years. Source — Wikipedia:
Portrait of Galen. By Georg Paul Busch (engraver) - The Lancet, Public domain, https://commons.wikimedia.org/w/index.php?curid=40855568
1025 CE
Ibn Sina's Canon of Medicine synthesizes physiology
Avicenna's encyclopedic Canon of Medicine integrated Galenic physiology with original observations on anatomy, disease, and drug action, becoming the standard medical text in Europe and the Islamic world for centuries. Source — Wikipedia:
The Persian manuscript copy of The Canon of Medicine in Museum and Mausoleum of Avicenna, Hamedan, Iran. By Coffeetalkh - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11906621
1242 CE
Ibn al-Nafis discovers pulmonary circulation
The Arab physician Ibn al-Nafis described the circulation of blood through the lungs, correctly refuting Galen's invisible pores in the heart septum centuries before Harvey. Source — Wikipedia:
Photograph of statue of Ibn Al Nafis By Unknown author - Arabic book on ibn al Nafis Takrouri M.S. M & Khalaf M 2003, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4759221
1543 CE
Vesalius publishes corrected human anatomy
Andreas Vesalius's De humani corporis fabrica corrected numerous Galenic errors through direct dissection, providing the anatomical foundation upon which modern physiology would be built. Source — Wikipedia:
Vesalius publishes corrected human anatomy By Unknown author, Public domain, https://commons.wikimedia.org/w/index.php?curid=457251The fabric of the human body: Vesalius' illustrated anatomy | Christie's
1628 CE
Harvey demonstrates blood circulation
William Harvey's De Motu Cordis used quantitative arguments and vivisection to prove that blood circulates continuously through a closed system pumped by the heart, founding modern cardiovascular physiology. Source — Wikipedia:
Harvey demonstrates blood circulation By After Daniël Mijtens - National Portrait Gallery: NPG 5115, Public domain, https://commons.wikimedia.org/w/index.php?curid=5975113Ceaseless motion: William Harvey's experiments in circulation
1665 CE
Malpighi observes capillaries under microscope
Marcello Malpighi discovered capillaries in frog lungs, completing Harvey's circulatory model by showing the physical connection between arteries and veins. Source — Wikipedia:
Marcello Malpighi, oil on canvas By Carlo Cignani - http://www.gettyimages.co.uk/detail/news-photo/portrait-of-marcello-malpighi-by-carlo-cignani-17th-century-news-photo/450079329, Public domain, https://commons.wikimedia.org/w/index.php?curid=41278580
1780 CE
Galvani discovers bioelectricity in frog legs
Luigi Galvani showed that frog muscles twitch when stimulated by electricity, launching the field of electrophysiology and the study of nerve-muscle function in animals. Source — Wikipedia:
Portrait of Luigi Galvani (1737-1798), Italian physicist By Unidentified painter - http://www.museopalazzopoggi.unibo.it//poggi_eng/palazzo/foto/prot http://biografieonline.it/foto-di.htm?n=Luigi+Galvani, Public domain, https://commons.wikimedia.org/w/index.php?curid=2707375How Luigi Galvani's Frog Leg Experiment Made a Dead Frog Jump & Invented the Battery
1807 CE
Cuvier establishes comparative anatomy framework
Georges Cuvier's Leçons d'anatomie comparée systematized the comparison of organ structures across animal groups, providing the structural basis for later comparative physiological studies. Source — Wikipedia:
description: Georges Cuvier *source: http://www.lib.utexas.edu/ *license: public domain By Georges_Cuvier.jpg: Unknown derivative work: Beao - Georges_Cuvier.jpg, Public domain, https://commons.wikimedia.org/w/index.php?curid=9710381
1849 CE
Berthold proves glands secrete into blood
Arnold Berthold transplanted testes in castrated roosters and showed that secondary sexual characteristics were maintained, providing the first experimental proof of endocrine function via the bloodstream. Source — Wikipedia:
Arnold Adolph Berthold or Arnold Adolf Berthold (1803 - 1861) By Unknown author - http://ihm.nlm.nih.gov/images/B01484, Public domain, https://commons.wikimedia.org/w/index.php?curid=18623988
1851 CE
Bernard discovers glycogenic liver function
Claude Bernard demonstrated that the liver produces glucose from glycogen, establishing the concept of internal secretion and homeostasis that became central to comparative endocrinology. Source — Wikipedia:
Claude Bernard. By Unknown author - [1], Public domain, https://commons.wikimedia.org/w/index.php?curid=11647284
1878 CE
Bert pioneers comparative and aviation physiology
Paul Bert's La Pression barométrique studied physiological effects of altitude and pressure across species, founding both aviation physiology and the rigorous experimental comparison of animal functions. Source — Wikipedia:
Paul Bert (17 October 1833 – 11 November 1886) By Théodore Truchelut / Félix Théodore Valkman - [1] [2], Public domain, https://commons.wikimedia.org/w/index.php?curid=16480093
1902 CE
Bayliss and Starling discover secretin
William Bayliss and Ernest Starling discovered that the intestinal hormone secretin is released into the blood to stimulate pancreatic secretion, coining the term 'hormone' and launching endocrinology. Source — Wikipedia:
Ideogram of human chromosome. Chromosome 11 highlighted. G-band, 850 bphs (bands per haploid set). Black and gray: Giemsa positive. Red: Centromere. Light blue: Variable region. Dark blue: Stalk. By National Center for Biotechnology Information, U.S. National Library of Medicine - NCBI's Genome Decoration Page., Public domain, https://commons.wikimedia.org/w/index.php?curid=61368958
1913 CE
Krogh wins Nobel for capillary physiology
August Krogh's work on capillary regulation of blood flow in different tissues across species earned him the Nobel Prize and established key principles of comparative cardiovascular physiology. Source — Wikipedia:
The Danish scientist August Krogh. By Bain News Service - This image is available from the United States Library of Congress's Prints and Photographs division under the digital ID ggbain.32006.This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing., Public domain, https://commons.wikimedia.org/w/index.php?curid=6054454
1921 CE
Banting and Best isolate insulin
Frederick Banting and Charles Best extracted insulin from dog pancreas, demonstrating that an endocrine hormone could treat diabetes and opening the modern era of endocrine therapy. Source — Wikipedia:
Photograph of F. G. Banting By Louis Schmidt - University of Toronto, Libraries, Public domain, https://commons.wikimedia.org/w/index.php?curid=44331721Heritage Minutes: The Discovery of Insulin
1949 CE
Tinbergen formalizes ethology's four questions
Nikolaas Tinbergen published 'The Study of Instinct,' framing animal behavior through causation, survival value, evolution, and ontogeny, providing the conceptual foundation for neuroethology. Source — Wikipedia:
Nikolaas Tinbergen (right), Konrad Lorenz (left) By Lorenz_and_Tinbergen2.jpg: Max Planck Gesellschaft derivative work: Materialscientist - This file was derived from: Lorenz and Tinbergen2.jpg:, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20425349
1952 CE
Hodgkin and Huxley model nerve action potential
Alan Hodgkin and Andrew Huxley used the squid giant axon to derive the ionic basis of action potentials, a cornerstone of neurophysiology that underpins all later neuroethological work. Source — Wikipedia:
Schematic of the basic Hodgkin-Huxley model of a neuron. By Krishnavedala - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=21725464
1961 CE
von Frisch decodes the honeybee waggle dance
Karl von Frisch demonstrated that honeybees communicate food location through a waggle dance, a landmark in neuroethology showing how neural mechanisms produce complex adaptive behavior. Source — Wikipedia:
Bee dance By Own work - File:Bee dance.png File:Sun01.svg File:Abeille-bee.svg by Emmanuel Boutet File:RosendeutschschweizerBlatt.svg by Kilom691, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=15242410The Waggle Dance of the Honeybee
1965 CE
Scharrer founds neuroendocrinology
Berta and Ernst Scharrer established the concept of neurosecretion, showing that neurons can release hormones, bridging neuroscience and endocrinology into the new field of neuroendocrinology. Source — Wikipedia:
1971 CE
O'Keefe discovers place cells in hippocampus
John O'Keefe discovered that specific hippocampal neurons fire when a rat occupies a particular location, founding the study of the neural basis of spatial navigation in animals. Source — Wikipedia:
An example of the spiking activity of neurons in the CA1 subregion of the hippocampus, commonly referred to as place cells. By Stuartlayton - I personally created this image using data I collected during my graduate studies., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=43746578
1977 CE
Guillemin and Schally isolate hypothalamic hormones
Roger Guillemin and Andrew Schally isolated and characterized hypothalamic releasing hormones, revealing how the brain controls the pituitary endocrine axis and earning the Nobel Prize. Source — Wikipedia:
1975 Award Winner - Roger C.L. Guillemin By Unknown author - http://resource.nlm.nih.gov/101441443, Public domain, https://commons.wikimedia.org/w/index.php?curid=71024445
1992 CE
Prosser publishes Comparative Animal Physiology
C. Ladd Prosser's textbook, refined across multiple editions, codified comparative physiology as a discipline, integrating endocrinology, neurobiology, and environmental adaptation across the animal kingdom. Source — Wikipedia:
2014 CE
Moser and Moser win Nobel for grid cells
May-Britt and Edvard Moser discovered grid cells in the entorhinal cortex that create a spatial coordinate system, extending comparative neuroethology of navigation to its cellular mechanism. Source — Wikipedia:
Trajectory of a rat through a square environment is shown in black. Red dots indicate locations at which a particular entorhinal grid cell fired. By Khardcastle - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=59507352
2023 CE
Comparative endocrinology meets climate change
Researchers increasingly apply comparative endocrine tools to study how hormonal systems in diverse species respond to climate-driven stressors, linking organismal physiology to global environmental change. Source — Wikipedia:
