Title: Thomas Hunt Morgan
Content:  Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in  1933 for discoveries elucidating the role that the chromosome plays in heredity. Morgan received his Ph.D. from Johns Hopkins University in zoology in 1890 and researched embryology during his tenure at Bryn Mawr. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly Drosophila melanogaster. In his famous Fly Room at Columbia University's Schermerhorn Hall, Morgan demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. During his distinguished career, Morgan wrote 22 books and 370 scientific papers. As a result of his work, Drosophila became a major model organism in contemporary genetics. The Division of Biology which he established at the California Institute of Technology has produced seven Nobel Prize winners.
Title: Thomas Hunt Morgan Medal
Content:  The Thomas Hunt Morgan Medal is awarded by the Genetics Society of America (GSA) for lifetime contributions to the field of genetics. The medal is named after Thomas Hunt Morgan, the 1933 Nobel Prize winner, who received this award for his work with Drosophila and his "discoveries concerning the role played by the chromosome in heredity." Morgan recognized that Drosophila, which could be bred quickly and inexpensively, had large quantities of offspring and a short life cycle, would make an excellent organism for genetic studies. His studies of the white-eye mutation and discovery of sex-linked inheritance provided the first experimental evidence that chromosomes are the carriers of genetic information. Subsequent studies in his laboratory led to the discovery of recombination and the first genetic maps. In 1981 the GSA established the Thomas Hunt Morgan Medal for lifetime achievement to honor this classical geneticist who was among those who laid the foundation for modern genetics.
Title: Thomas Hunt Morgan
Content: Johns Hopkins awarded Morgan an honorary LL.D. and the University of Kentucky awarded him an honorary Ph.D. ; He was elected Member of the National Academy of Sciences in 1909. ; He was elected a Foreign Member of the Royal Society (ForMemRS) in 1919 ; In 1924 Morgan received the Darwin Medal. ; The Thomas Hunt Morgan School of Biological Sciences at the University of Kentucky is named for him. ; The Genetics Society of America annually awards the Thomas Hunt Morgan Medal, named in his honor, to one of its members who has made a significant contribution to the science of genetics. ; Thomas Hunt Morgan's discovery was illustrated on 
Title: Thomas Hunt Morgan
Content:  race of those mutations that are beneficial to the life and reproduction of the organism". Injurious mutations have practically no chance of becoming established. Far from rejecting evolution, as the title of his 1916 book may suggest, Morgan laid the foundation of the science of genetics. He also laid the theoretical foundation for the mechanism of evolution: natural selection. Heredity was a central plank of Darwin's theory of natural selection, but Darwin could not provide a working theory of heredity. Darwinism could not progress without a correct theory of genetics. By creating that foundation, Morgan contributed to the neo-Darwinian synthesis, despite his criticism of Darwin at the beginning of his career. Much work on the Evolutionary Synthesis remained to be done.
Title: Thomas Hunt Morgan
Content:  1989 stamp issued in Sweden, showing the discoveries of eight Nobel Prize-winning geneticists. ; A junior high school in Shoreline, Washington was named in Morgan's honor for the latter half of the 20th century. Morgan left an important legacy in genetics. Some of Morgan's students from Columbia and Caltech went on to win their own Nobel Prizes, including George Wells Beadle and Hermann Joseph Muller. Nobel prize winner Eric Kandel has written of Morgan, "Much as Darwin's insights into the evolution of animal species first gave coherence to nineteenth-century biology as a descriptive science, Morgan's findings about genes and their location on chromosomes helped transform biology into an experimental science." 
Title: Thomas Hunt Morgan
Content:  carrying out their own experiments. He returned to embryology and worked to encourage the spread of genetics research to other organisms and the spread of the mechanistic experimental approach (Enwicklungsmechanik) to all biological fields. After 1915, he also became a strong critic of the growing eugenics movement, which adopted genetic approaches in support of racist views of "improving" humanity. Morgan's fly-room at Columbia became world-famous, and he found it easy to attract funding and visiting academics. In 1927 after 25 years at Columbia, and nearing the age of retirement, he received an offer from George Ellery Hale to establish a school of biology in California.
Title: Eugenics
Content:  The first major challenge to conventional eugenics based on genetic inheritance was made in 1915 by Thomas Hunt Morgan. He demonstrated the event of genetic mutation occurring outside of inheritance involving the discovery of the hatching of a fruit fly (Drosophila melanogaster) with white eyes from a family with red eyes, demonstrating that major genetic changes occurred outside of inheritance. Additionally, Morgan criticized the view that certain traits, such as intelligence and criminality, were hereditary because these traits were subjective. Despite Morgan's public rejection of eugenics, much of his genetic research was adopted by proponents of eugenics. The heterozygote test is 
Title: Modern synthesis (20th century)
Content:  Thomas Hunt Morgan began his career in genetics as a saltationist and started out trying to demonstrate that mutations could produce new species in fruit flies. However, the experimental work at his lab with the fruit fly, Drosophila melanogaster demonstrated that rather than creating new species in a single step, mutations increased the supply of genetic variation in the population. By 1912, after years of work on the genetics of fruit flies, Morgan showed that these insects had many small Mendelian factors (discovered as mutant flies) on which Darwinian evolution could work as if the variation was fully continuous. The way was open for geneticists to conclude that Mendelism supported Darwinism.
Title: Thomas Hunt Morgan
Content:  mutation theory with his experimental heredity work. He was initially skeptical of Mendel's laws of heredity (as well as the related chromosomal theory of sex determination), which were being considered as a possible basis for natural selection. Following C. W. Woodworth and William E. Castle, around 1908 Morgan started working on the fruit fly Drosophila melanogaster, and encouraging students to do so as well. With Fernandus Payne, he mutated Drosophila through physical, chemical, and radiational means. He began cross-breeding experiments to find heritable mutations, but they had no significant success for two years. Castle had also had difficulty identifying mutations in Drosophila, which were tiny. Finally 
Title: Thomas Hunt Morgan
Content:  to distinguish internal and external causes to shed light on the Roux-Driesch debate. He wrote his first book, The Development of the Frog's Egg (1897). He began a series of studies on different organisms' ability to regenerate. He looked at grafting and regeneration in tadpoles, fish and earthworms; in 1901 he published his research as Regeneration. Beginning in 1900, Morgan started working on the problem of sex determination, which he had previously dismissed when Nettie Stevens discovered the impact of the Y chromosome on sex. He also continued to study the evolutionary problems that had been the focus of his earliest work.

Question: which of the following was a contribution thomas hunt morgan made to genetics?
Answer: Chromosome.