|Page Back||Unit Up: Science||Page Next|
|Unit Back: Science||References||Unit Next Timeline|
Waddington, Conrad Hal: (1905-1975), British zoologist, developmental biologist, paleontologist, geneticist, embryologist and philosopher who laid the foundations for systems biology. He had wide interests that included poetry and painting, as well as left-wing political leanings.
Waddington's epigenetic landscape is a metaphor for how gene regulation modulates development. One is asked to imagine a number of marbles rolling down a hill towards a wall. The marbles will compete for the grooves on the slope, and come to rest at the lowest points. These points represent the eventual cell fates, that is, tissue types. Waddington coined the term Chreode to represent this cellular developmental process. This idea was actually based on experiment: Waddington found that one effect of mutation (which could modulate the epigenetic landscape) was to affect how cells differentiated. He also showed how mutation could affect the landscape and used this metaphor in his discussions on evolution; he was the first person to emphasise that evolution mainly occurred through mutations that affected developmental anatomy. (Wikipedia)
Alfred Russel Wallace (1823–1913) British naturalist, explorer, geographer, anthropologist and biologist. He is best known for independently proposing a theory of evolution due to natural selection that prompted Charles Darwin to publish his own theory. Wallace did extensive fieldwork, first in the Amazon River basin and then in the Malay Archipelago, where he identified the Wallace Line that divides the Indonesian archipelago into two distinct parts, one in which animals closely related to those of Australia are common, and one in which the species are largely of Asian origin. He was considered the 19th century's leading expert on the geographical distribution of animal species and is sometimes called the "father of biogeography".
He believed qualitative novelties could arise through the process of evolution, in particular the phenomena of life and mind, in a vitalistic manner. His advocacy of Spiritualism and his belief in a non-material origin for the higher mental faculties of humans strained his relationship with the scientific establishment, especially with other early proponents of evolution. In addition to his scientific work, he was a social activist who was critical of what he considered to be an unjust social and economic system in 19th-century Britain. (Wikipedia)
Ward, Peter Douglas: Professor of geological sciences at the University of Washington in Seattle, where he is also adjunct professor of zoology and of astronomy. Author of several books on biodiversity and the fossil record, including Rivers in Time: The Search for Clues to Earth's Mass Extinctions and Rare Earth: Why Complex Life is Uncommon in the Universe (with Donald Brownlee). He is the principal investigator for the University of Washington's portion of the NASA Astrobiology Institute. (PBS evolution Glossary)
Wegener, Alfred: A German climatologist and geophysicist whose book, The Origins of Continents and Oceans, was the first to propose the concept of continental drift (the forerunner to the theory of plate tectonics), as well as to suggest a supercontinent called Pangaea, which Wegener suggested had fragmented into the continents as we know them today. His ideas remained controversial until the 1960s, when they became widely accepted as new evidence led to the development of the concept of plate tectonics. (PBS evolution Glossary)
Weismann, August (1834-1914), German zoologist, cytologist and evolutionary theorist, considered by Ernst Mayr the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Developed germ plasm theory, according to which inheritance only takes place by means of the germ cells (the gametes such as egg cells and sperm cells). Sexual reproduction (recombination) creates in every generation a new, variable population of individuals, which then acts on this variation and determines the course of evolutionary change. Genetic information cannot pass from soma (the rest of the cells) to germ plasm (the Weismann barrier). This refutes out Lamarck's theory of inheritance of acquired characteristics. The idea of the Weismann barrier is central to Neo-Darwinism and the Modern evolutionary synthesis (Wikipedia, Kutschera & Niklas 2004, p.260)
Wilson, Edward Osborne: (b. 1929) American biologist and professor at Harvard University, researcher (sociobiology, biodiversity), theorist (consilience, biophilia), naturalist, conservationist, and author. His biological specialty is myrmecology, the study of ants. Wilson has won two Pulitzer Prizes for his books On Human Nature and The Ants, and has received numerous honors for his research and conservation efforts. (Wikipedia; (PBS evolution Glossary))
Woese, Carl Richard : (b. 1928) American microbiologist and physicist who brought about a paradigm revolution in our understanding of the tree of life. In 1977, Carl Woese proposed that Archaea are different from normal bacteria and constitute a new super-kingdom Archaebacteria. His three-domain system, based upon genetic relationships rather than obvious morphological similarities, divided life into 23 main divisions, all incorporated within three domains: Bacteria, Archaea, and Eucarya. This was based on phylogenetic taxonomy of 16S ribosomal RNA, a technique pioneered by Woese and which is now standard practice. Despite being published in a top scientific journal (PNAS), his publication was not read widely. Furthermore, it was not greeted with enthusiasm by the scientific community, especially by Salvador Luria, Nobel Prize winner in Medicine, and later by others. As a consequence, he was not invited to conferences to speak about his work or defend it. His three domain model was not rejected because of the data, but because it violated the central dogma of prokaryote-eukaryote dichotomy. In contrast to the Darwinian idea of a Common Descent of all life, Woese argued that there is not a single ancestor or root of the tree of life, but a network of organisms life forms that horizontally exchanged genetic material. Even evolutionary biologist Ernst Mayr (1904-2005), an icon of evolutionary biology, was one of a number of scientists who vigorously opposed Woese's (and Norman Pace's) suggestion that the catch-all term prokaryote be rejected. In 1990 Woese adopted the term 'domain' for the three branches of life and shortened the name Archaebacteria to Archaea. Textbooks teach the third domain now as a matter of fact, but omit the initial hostile reaction to Woese's ideas.
Woese's work is also significant in terms of its implications for the search for life on other planets. Prior to Woese, Archaea were thought to be extreme organisms that had evolved from the organisms that are more familiar to us. Many scientists now believe they are ancient, and may have robust evolutionary connections to the first organisms to live on Earth. Organisms similar to those Archaea that exist in extreme environments may have found a foothold on other planets, some of which are known to harbor conditions conducive to extremophile life. Woese was also the originator of the RNA world hypothesis, although not by that name. (Carl Woese: from scientific dissident to textbook orthodoxy ,Wikipedia)
Wright, Sewall: (1889–1988) American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. With R. A. Fisher and J.B.S. Haldane, he was a founder of theoretical population genetics. (Wikipedia)
new page MAK111204