Articles

Displaying 951 - 960 of 1144 items.

Ernst Heinrich Philipp August Haeckel (1834-1919)

By Karen Wellner

Ernst Heinrich Philipp August Haeckel was a prominent comparative anatomist and active lecturer in the late nineteenth and early twentieth centuries. He is most well known for his descriptions of phylogenetic trees, studies of radiolarians, and illustrations of vertebrate embryos to support his biogenetic law and Darwin's work with evolution. Haeckel aggressively argued that the development of an embryo repeats or recapitulates the progressive stages of lower life forms and that by studying embryonic development one could thus study the evolutionary history of life on earth.

Format: Articles

Subject: People

Ernest Everett Just (1883-1941)

By Karen Wellner

Ernest Everett Just was an early twentieth century American experimental embryologist involved in research at the Marine Biological Laboratory (MBL) at Woods Hole, Massachusetts, and the Stazione Zoologica in Naples, Italy. Just was known for simple but elegant experiments that supported the "fertilizing" theory of Frank R. Lillie and served as an antagonist to Jacques Loeb's work with artificial parthenogenesis.

Format: Articles

Subject: People

Ziegler Wax Embryo Models

By Karen Wellner

Three-dimensional anatomical models have long been essential to the learning of science and lend a sense of "control" to those practicing in the field. As the development of embryology grew in importance during the late 1800s, so did the need for models to show intricate details of embryos.

Format: Articles

Subject: Technologies, Reproduction

José Pedro Balmaceda (1948- )

By Hilary Gilson

José Pedro Balmaceda was born 22 August 1948 in Santiago, Chile. His mother Juanita owned a women's boutique in the city and his father José was a successful owner of several timber mills. He grew up with five sisters who remained in Santiago all their lives. Balmaceda attended the college preparatory school San Ignatius where he met Sergio Stone, his future partner at the Center for Reproductive Health fertility clinic in the University of California Irvine Medical Center.

Format: Articles

Subject: People, Reproduction

The Mechanistic Conception of Life (1912), by Jacques Loeb

By Steve Elliott

Jacques Loeb published The Mechanistic Conception of Life in 1912. Loeb's goal for the book was to further disseminate his explanations of organic processes, such as embryonic development and organisms orientations to their environments, which relied on physics and chemistry. Loeb also wanted to provide an alternative explanatory framework to vitalism and what he called romantic evolutionism, then both widespread.

Format: Articles

Subject: Publications

Hans Spemann (1869-1941)

By Karen Wellner

Hans Spemann was an experimental embryologist best known for his transplantation studies and as the originator of the "organizer" concept. One of his earliest experiments involved constricting the blastomeres of a fertilized salamander egg with a noose of fine baby hair, resulting in a partially double embryo with two heads and one tail.

Format: Articles

Subject: People

Artificial Parthenogenesis and Fertilization (1913), by Jacques Loeb

By Karen Wellner

Jacques Loeb is best known for his embryological work investigating parthenogenesis in invertebrates. Artificial Parthenogenesis and Fertilization is a revised and English-translated work from his earlier book, Die chemische Entwicklungserregung des tierischen Eies (1900). Artificial Parthenogenesis describes Loeb's many and varied methodical experiments to initiate egg development without fertilization by sperm. As is true with much of science, some of Loeb's experiments were successful and many were not.

Format: Articles

Subject: Publications

Stem Cell Tourism

By Christina Raup

When James Thomson of the University of Wisconsin announced in 1998 that he had derived and cultured human embryonic stem cells(hESCs), Americans widely believed-and accepted-that stem cells would one day be the basis of a multitude of regenerative medical techniques. Researchers promised that they would soon be able to cure a variety of diseases and injuries such as cancer, diabetes, Parkinson's, spinal cord injuries, severe burns, and many others. But it wasn't until January 2009 that the Food and Drug Administration approved the first human clinical trials using hESCs.

Format: Articles

Subject: Theories, Ethics

John von Neumann's Cellular Automata

Cellular automata (CA) are mathematical models used to simulate complex systems or processes. In several fields, including biology, physics, and chemistry, CA are employed to analyze phenomena such as the growth of plants, DNA evolution, and embryogenesis. In the 1940s John von Neumann formalized the idea of cellular automata in order to create a theoretical model for a self-reproducing machine. Von Neumann's work was motivated by his attempt to understand biological evolution and self-reproduction.

Format: Articles

Subject: Theories

Pope Pius XII (1876-1958)

By Katherine Brind'Amour

Pope Pius XII was born Eugenio Maria Giuseppi Giovanni Pacelli on 2 March 1876 in Rome, Italy, to Virginia and Filippo Pacelli. Known for his oft-disputed role in the Roman Catholic Church's approach to the Nazis and World War II, Pope Pius XII also contributed a number of important documents regarding conception, fertility, abortion, and reproductive control to the Vatican's collection of writings and doctrine on procreation.

Format: Articles

Subject: People, Religion, Reproduction