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Hugo de Vries is born in Haarlem, The Netherlands.
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-Hugo De Vries first pursued a degree in botany from Leiden University in Leiden, The Netherlands. (Grad. 1870)
-Then he attented Heidelberg University (Heidelberg, Baden-Württemberg, Germany) to study Chemistry and Physics. (One semester.)
-Then De Vries went to Wurzberg to study plant growth periodically between his teachings. -
Thomas Morgan was born in Lexington, Kentucky, U.S.A.
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De Vries taught geology, bootany, and zoology at various schools in Amsterdam throughout this period.
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This period of time was known as "The Eclipse of Darwinism". Scientists all over the world were rejecting Darwin's ideas about evolution (Natural Selection), and were trying to come up with their own ideas.
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De Vries helped in researching osmosis in plant physiology. He came up with a relationship between osmotic pressure and the molecular weight of substances in plant cells.
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De Vries was a professor at the University of Amsterdam for this time period. He did various research (Pangenes, mutations, heredity).
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De Vries moved to Germany where he met, then married Elisabeth Louise Egeling in 1879.
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The first Boer War took place during the lives of both Morgan and De Vries. Morgan was very young.
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Thomas Morgan completed a Bachelor of Science Degree at the University of Kentucky, U.S.A.
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De Vries took nine evening primroses and began a long term experiment to try and identify individuals with new traits. Out of 15,000 offspring between these nine primroses he found two new types and five plants of each type. This became the basis of his work in genes and mutations.
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After Graduating with his Bachelor of Science degree, Thomas Morgan went to Johns Hopkins University, Baltimore, Maryland, U.S.A, to complete graduate studies in Zoology.
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Thomas Morgan examined the embryology of Sea Spiders at Josh Hopkins University. This work inspired him to focus his research largely on experimental embryology during his time at Bryn Mawr College.
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De Vries hypothesized that his plants had pangenes that were passed from one generation to the next. These are now known to be called genes. This theory was published in his book, "Intracellular Pangenesis" in 1889.
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Thomas Morgan recieved his PhD in Zoology from Josh Hopkins University, Baltimore, Maryland, U.S.A.
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Thomas Morgan worked as an associate professor of Biology at Bryn Mawr College for Women, Pennyslvania, U.S.A.
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De Vries claimed he discovered Mendel's Laws without actually knowing that they had been discovered. That was highly disputed. When De Vries published a paper in 1900 he gave credit to Mendel.
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De Vries performed experiments in the late 1890's and was later given credit on re-discovering Mendel's three-to-one ratio for a recessive trait.
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The second Boer War took place during the lives of both Morgan and De Vries.
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De Vries publishes his book: "The Mututation Theory (Die Mutationstheorie)". This book included his theory that there could be mutations from the original line of species.
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De Vries made a lecture tour across the United States. He explained all of his theories on it.
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De Vries gave the opening speech for the Station for Experimental Study of Evolution at Cold Spring Harbor, Long Island, U.S.A.
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Thomas Morgan married one of his graduate students at Bryn Mawr University. Her name was Lillian V. Sampson; a cytologist and embryologist.
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Thomas Morgan then became a professor of experimental Zoology at Columbia University, New York, U.S.A.
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De Vries publishes his book: "Species and Varieties: Their Origin by Mutation".
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Thomas Morgan found a male Fruit fly with white eyes instead of red. A mutation. He crossed it with a female red eyed, fruit fly and all of the offspring were red eyed. They kept crossing the offspring and ended up with the Mendelian 3:1 ratio for a recessive trait. (Only males usually had white eyes.)
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One of Morgan's papers was published, in which he outlined three of his major findings: 1. Genes must be on chromosomes. 2. Genes must be on a particular chromosome. 3. The gene for eye color in fruit fly's must be on the sex chromosome.
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Morgan said that, to cause mutations, linked genes could separate. He implied the process of "chromosome recombination". (Pairs of chromosomes could exchange or crossover between one another.) He also later came up with the idea that this was directly related to the distance the genes were on a chromosome.
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While at Columbia, Morgan created a room for research on fruit flys. With the help of his students he developed ideas with proof, for chromosomal theory of heredity, genetic linkage, chromosomal crossing over and non-disjunction.
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World War I occured during the life of Hugo de Vries and Thomas Morgan.
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De Vries retired in 1918 from teaching at the University of Amsterdam.
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Thomas Morgan was appointed a professor of Biology and a director of the G. Kerckhoff Laboratories at the California Institute of Technology, in Pasadena, California, U.S.A.
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The Great Depression occured during the lives of both Morgan and De Vries.
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Thomas Morgan recieved the Nobel Prize in Physiology or Medicine, for his work in establishing the chromosomal theory of inheritance.
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World War II went on in the life of Thomas Morgan. However, Thomas Morgan was an old man and for the majority of the war, was retired.
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Thomas Morgan retired from his position at the California Instution of Technology.
