Archives containing the RDF files for *all* our books can be downloaded at https://book.klll.cc/wiki/Gutenberg:Feeds#The_Complete_Project_Gutenberg_Catalog Project Gutenberg 2018-07-07 Public domain in the USA. 191 Morgan, Thomas Hunt 1866 1945 Morgan, T. H. (Thomas Hunt) 19014430 The genetic and the operative evidence relating to secondary sexual characters Carnegie Institution of Washington publication no. 285 Produced by Larry B. Harrison, Bryan Ness, Chuck Greif and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was produced from images generously made available by The Internet Archive/American Libraries.) "The Genetic and the Operative Evidence Relating to Secondary Sexual Characters" by T.H. Morgan is a scientific publication written in the early 20th century. This work delves into the genetic and physiological aspects of secondary sexual characteristics in birds, particularly focusing on the Sebright bantam and other fowl as subjects for analysis. It covers various experiments and findings related to plumage differences between hen-feathered and cock-feathered males, exploring how these traits are influenced by factors such as heredity and endocrine signaling. The opening of the book sets the stage for an in-depth study of the genetic mechanisms at play in determining secondary sexual characteristics. It begins with a discussion of the existence of two male types within certain poultry breeds and introduces the author's experimentation with castrating hen-feathered Sebrights to observe changes in plumage. Morgan recounts his observations regarding the physical alterations in feathering post-operation, revealing insights into the relationship between the gonads and plumage expression. This portion establishes not only the methodology and initial findings but also hints at the broader implications for understanding sexual differentiation in birds. (This is an automatically generated summary.) Reading ease score: 57.3 (10th to 12th grade). Somewhat difficult to read. en Poultry Sex (Biology) Genetics QH Text Category: Science - Biology 394947 2025-09-23T04:38:56.184637 text/html 390806 2021-01-24T14:44:46 text/html 1429642 2025-09-23T04:39:02.877661 application/epub+zip 1428437 2025-09-23T04:38:57.465652 application/epub+zip 178179 2025-09-23T04:38:56.781643 application/epub+zip 1537676 2025-09-23T04:39:06.868620 application/x-mobipocket-ebook 1506466 2025-09-23T04:39:01.911663 application/x-mobipocket-ebook 270661 2022-08-25T18:53:55.408078 application/x-mobipocket-ebook 353541 2025-09-23T04:38:55.364649 text/plain; charset=us-ascii 353391 2018-07-07T13:07:58 text/plain; charset=us-ascii 18849 2025-09-23T04:39:07.034626 application/rdf+xml 12902 2025-09-23T04:38:56.871675 image/jpeg 2327 2025-09-23T04:38:56.827641 image/jpeg 120420 2018-07-07T13:08:00 application/octet-stream application/zip 1353239 2021-01-24T14:44:46 application/octet-stream application/zip 1368965 2025-09-23T04:38:56.267677 application/octet-stream application/zip en.wikipedia