Embryo Project Encyclopedia

During the 1870s and early 1880s, the British morphologist Francis Maitland Balfour contributed in important ways to the budding field of evolutionary embryology, especially through his comparative embryological approach to uncovering ancestral relationships between groups. As developmental biologist and historian Brian Hall has observed, the field of evolutionary embryology in the nineteenth century was the historical ancestor of modern-day evolutionary developmental biology. Balfour's work was notably inspired by Charles Darwin's theory of evolution and Ernst Haeckel's account of the relationships between embryology and evolution. Only a decade after Balfour's program of research began, an alpine climbing accident robbed Britain of its most promising embryologist.

In 1962 the journal Acta Biotheoretica published the final work of the biologist Edward Stuart Russell, a full eight years after his death. Entitled The Diversity of Animals: an Evolutionary Study, this short, unfinished manuscript on evolution received little recognition in the scientific presses despite both its technical discussion of adaptations in decapods (crabs, shrimp, etc.) and its different approach to evolutionary theory. The precise reason for this neglect is unclear. This book is a continuation of Russell's philosophical perspective, organicism, an interpretation that focuses on the organism as the primary unit of analysis for the biological sciences. Russell first argued for this position in several of his earlier works, such as The Interpretation of Development and Heredity (1930) and The Directiveness of Organic Activities (1946). What was new in The Diversity of Animals lies in Russell's orthogenetic theory of evolution. By "orthogenetic" he means evolutionary change in definite directions. The overall thesis of this work is that transformations in evolution that occur in early ontogenesis, or development, are the best explanation for most diversity in nature. The consequence of Russell's argument is that an understanding of development is fundamental to an explanation of the major transformations in the evolutionary history of life.

Hans Peter Dietz and Judy Simpson published, “Levator Trauma is Associated with Pelvic Organ Prolapse,” in the journal BJOG: An International Journal of Obstetrics and Gynecology in 2008. In their article, Dietz and Simpson estimated the risk of pelvic organ prolapse in women who attained injuries to the pelvic levator muscles. The levator muscles, also known as the levator ani, are a major muscle group that comprise the pelvic floor. Along with other muscles, the pelvic floor supports organs in a woman’s pelvis, such as the bladder, uterus, and rectum. Vaginal childbirth can cause a weakening of the pelvic muscles. That can lead to pelvic organ prolapse, which results in the descent of the pelvic organs towards a woman’s vaginal opening. In, “Levator Trauma is Associated with Pelvic Organ Prolapse,” Dietz and Simpson found that women were more likely to have pelvic organ prolapse if they had levator trauma, and called for further research to understand the relationship between levator ani trauma and pelvic organ prolapse.

In 1997, physicians and researchers Ambre Olsen, Virginia Smith, John Bergstrom, Joyce Colling, and Amanda Clark published, “Epidemiology of Surgically Managed Pelvic Organ Prolapse and Urinary Incontinence,” in the journal Obstetrics and Gynecology. In their article, the authors retrospectively analyzed data from patients who underwent surgery for pelvic organ prolapse or urinary incontinence two years prior in 1995. Often due to a weakening of or damage to their pelvic muscles, women with pelvic organ prolapse can experience a descent of pelvic organs into the lower pelvis and vagina. People with urinary incontinence can experience bladder control issues and urinary leaks. According to the authors, an estimated fifty percent of women who have previously given birth have had a prolapse. In their article, Olsen and colleagues analyze factors such as race, age, and weight in women who had surgery to treat pelvic organ prolapse and ultimately advocate for a standard assessment for the severity of those conditions.

In 1996, a team of researchers associated with the International Continence Society published “The Standardization of Terminology of Female Pelvic Organ Prolapse and Pelvic Floor Dysfunction” in American Journal of Obstetrics and Gynecology. Pelvic organ prolapse is characterized by the descent of the pelvic organs into the lower portion of the pelvis and is often caused by a weakening of the muscles and ligaments that normally hold the organs in place. The authors concluded that physicians and researchers needed to develop a system of standardized terms to use to describe the anatomical position of pelvic organ prolapse in women. They propose using terms that emphasize the location of the prolapse rather than just the involved organ. They also suggest that the system utilizes a series of examinations and imaging to uniformly describe and quantify pelvic organ prolapse. The article by Bump and colleagues was one of the first to call for a standardized system using specific terms to communicate findings about pelvic organ prolapse systematically across clinical and academic research settings.

In 2007, physicians John Jelovsek, Christopher Maher, and Matthew Barber published, “Pelvic Organ Prolapse,” in The Lancet. In their article, Jelovsek and colleagues provided an overview of pelvic organ prolapse in women and described the epidemiology, risk factors, symptoms, and management of the condition. Pelvic organ prolapse occurs when a woman’s pelvic floor is weakened or damaged from stress or trauma such as vaginal childbirth. The pelvic floor is a group of muscles that provides support to organs within the lower abdominal region of the body, including the bladder, uterus, and rectum. Disorders of the pelvic floor disrupt its normal function, often causing a feeling of uncomfortable pressure or pain, and incontinence, which is involuntary leakage of urine or feces. In their article, Jelovsek and colleagues reviewed the known information about pelvic organ prolapse as of 2007 and research teams who further studied the causes and management of pelvic organ prolapse in women later used the article as a reference.

Pelvic organ prolapse is a common condition in women that causes the pelvic organs to descend, often resulting from a weakened pelvic floor. Pelvic organs supported by the pelvic floor, such as the bladder, bowel, or uterus, can descend to such a degree that they project out from a woman’s body typically via the vagina. Pelvic floor stress or trauma, like vaginal childbirth, can cause pelvic organ prolapse. Women with pelvic organ prolapse also often experience other conditions, such as incontinence or the involuntary leakage of urine or fecal matter. As a result, while many women experience pressure or fullness from the prolapse itself, other common symptoms of pelvic organ prolapse are those involving the bladder or the bowel. Treatments for prolapse depend on the woman’s symptoms, and include pessaries, surgery, and pelvic floor exercises. As of 2021, researchers and physicians continue to study pelvic organ prolapse to determine how different treatments can be tailored to specific causes or symptoms.

Of Sir D'Arcy Thompson's nearly 300 publications, the theoretical treatise On Growth and Form, first published in 1917, remains the principal work for which he is remembered. This substantial book is still in print today, and merited an editorial review and introductory essays by two important twentieth century biologists, John Tyler Bonner and Stephen Jay Gould. Growth and Form was immediately well-received for both its literary style and its scientific significance, as discussed by the biologist Sir Peter Medawar. Despite being almost continuously in print since its first publication, the exact influence of Growth and Form on the biological sciences, although widely acknowledged, is yet difficult to characterize. In this work Thompson aimed to unite physics and biology through an analysis of the physical limitations to the growth and structure of organisms. For developmental biologists in particular, Thompson's theory on the transformation of biological forms, presented in the final chapter of Growth and Form, was thought provoking.

Edward Stuart Russell was born 23 March 1887 to Helen Cockburn Young and the Reverend John N. Russell in Port Glasgow, Scotland. Friends and co-workers alike knew Russell as a quiet and focused, though always kind and helpful person. Trained in classics and biology, Russell's interests drew him to the study of historical and philosophical issues in the biological sciences, particularly morphology and animal behavior. According to Nils Roll-Hansen, Russell was one of the most influential philosophers of biology in the second third of the twentieth century. It was through history and philosophy, rather than his equally important work as a fisheries biologist, Russell argued that developmental and embryological studies deserve a central role in the biological sciences.

In 2011, Cristian Persu, Christopher Chapple, Victor Cauni, Stefan Gutue, and Petrisor Geavlete published “Pelvic Organ Prolapse Quantification System (POP-Q) – A New Era in Pelvic Prolapse Staging,” in the Journal of Medicine and Life. In their article, the authors explain the need for a reliable diagnostic method for describing the state of a pelvic organ prolapse, or a condition that can result from weakness or damage to the muscles that support the pelvic organs, sometimes leading to bladder, bowel, and sexual dysfunction. Persu and colleagues describe a previous diagnostic method, the Baden-Walker Halfway Scoring System, comparing it to the newer system, the Pelvic Organ Prolapse Quantification System, referred to also as POP-Q. By examining the benefits and drawbacks of each pelvic organ prolapse measurement and diagnostic system, the authors proposed a universal acceptance of the POP-Q system, based on its accuracy and reliability.