William Harvey (April 1, 1578) was an English physician who was the first to study and provide experimental evidence for animal blood circulation. His book “Anatomical Exercise on the Motion of Heart and Blood in animals” was his key contribution to science. Harvey showed that the blood flows through the entire body by a single system of arteries and veins. It was thought that the blood used two circulation paths, one for red (oxygenated) blood using the arteries and one for the purple (non-oxygenated) blood running along the veins. His many experiments showed not only how blood circulate but also demonstrate other anatomical details such as vein valves and hearth structure.
Jane Goodall (April 3, 1934) was an English ethologist interested in animal behavior. Her long interest in animal behaviors and specially chimpanzees, led her to Africa were she immersed herself in their habitat as a companion rather that an observer. She showed that chimpanzees make use of tools and that they posses a complex society with long-term bonds and emotions. Goodall has written many books for adults and children, among the most influential are; Through a Window: My Thirty Years with the Chimpanzees of Gombe (1990), Africa In My Blood (2000), and Seeds of Hope: Wisdom and Wonder from the World of Plants (2014). The Jane Goodall institute is an organization set to study, protect, and conserve the species.
James D. Watson (April 6, 1928) was an American Geneticist and Biophysicist that in conjunction with Francis Crick, and Rosalind Franklin data was influential in determining the three dimensional structure of DNA. This great achievement has been critical for our understanding of how the double helix structure and hydrogen pairing between bases allows for replication of the DNA message. His many books include Molecular Biology of the Gene (1965), The Double Helix (1968), and The DNA Story (1981).
Melvin Calvin (April 8, 1911) was an American chemist that won the novel Prize in 1961 for his work on photosynthesis, and the elucidation of the Calvin Cycle. Calvin started his work as a chemist later expanding his interests into biochemistry specially the study of photosynthesis. Using isotopic tracing techniques and chromatography he identified the several chemical components of the biochemical pathway that convert CO2 into sugars or as is called the Calvin Cycle. He was a prolific writer of articles and books and founded an interdisciplinary research laboratory called the Calvin laboratory.
Max Planck (April 23, 1858) was a German theoretical physicist. He won the Nobel Prize in 1918 for his work on developing the quantum theory. His work shed light into the atomic and subatomic world. This led him to discover the Planck radiation Law and its famous constant that explain black body radiation. The Planck constant is a fundamental physical constant important in quantum mechanics because describes the behavior of particles and waves on the atomic level.