(May 28, 1807 – December 14, 1873) Swiss-born American zoologist, geologist, and paleontologist, with a special expertise in ichthyology. Founder and director of Harvard's Museum of Comparative Zoology, he was one of the most famous scientists of his day. His study of glacial erratics and other traces of past glaciation led Agassiz to propose the occurrence of past ice ages. he asserted that all of central Europe had once been buried beneath a massive sheet of ice.  He was the first scientist to realize that the immense prehistoric North American lake now known as Lake Agassiz, was created by glacial dams)1.

(11 September, 1522 — 4 May, 1605). Italian naturalist and physician, also known as Ulysses Aldrovandi, or simply as Aldrovandus. Together with Conrad Gesner, he led the Renaissance movement that placed a renewed emphasis on the study of the nature. The great naturalist Ulisse Aldrovandi taught for many years at the University of Bologna during the latter half of the sixteenth century. He also brought about the creation of the university's botanical gardens, in 1568, one of the first in Europe. Aldrovandi was nicknamed both the "Bolognese Aristotle" and the "Second Pliny." Aldrovandi'sNatural History was many thousands of pages long. It filled 14 folio volumes (10 published posthumously between 1606 and 1668). It had fine illustrations, and to a large extent, the descriptions were based on direct observation, unlike those of so many of his predecessors.

(1799-1847), Mary Anning, the great fossil hunter, lived throughout her life in the little seaside town of Lyme Regis in West Dorset on the south coast of England. The serendipity of this place of birth, and the gift of a penetrating eye, would bring Anning lasting fame. When she was 10 years old, her father, Richard Anning, died of the combined effects of tuberculosis and a serious fall. It was he who taught Mary how to find and clean fossils. After her father's death, Mary Anning went down one day to look for curiosities, the circumstances of the family not being good. She found an ammonite.Her age was about ten. A lady in the street, seeing the fossil in her hand, offered her half-a-crown for it, which she accepted, and from that moment fully determined to go down 'upon beach' again. In 1811, in a block of fallen shale, her brother Joseph found a massive skull (see figure right) that he mistook for a giant crocodile's. It lay mostly hidden beneath the sand. Mary went back to investigate, and over a period of months slowly picked away the rock to expose the remains. She eventually revealed an entire ichthyosaur — the first complete specimen ever discovered. She was just twelve years old at the time. In 1828, she found the first specimen of the pterosaur Dimorphodon macryonx (see figure right), a strange winged creature with a huge head like a toucan's. The next year she discovered a fossil fish, Squaloraja ,a weird thing halfway between shark and ray. Then, in 1830, she found a new, large-headed plesiosaur. This she managed to sell for 200 guineas (£210) — more than a year's income for many people. She was visited and consulted by many eminent scientists of the era. She was the acknowledged expert in many aspects of paleontology.

(1929-) Swiss microbiologist and geneticist. Shared the 1978 Nobel Prize in Physiology or Medicine with Hamilton Smith and Daniel Nathans for the discovery of restriction endonucleases, which led to the development of recombinant DNA technology

(384-322 B.C.) Greek philosopher and early scientist. Often called the "father of biology." he was able to describe plant and animal specimens received from all parts of the far-flung Alexandrian empire. Aristotle wrote about 400 treatises, of which some 30 survive.  He explicitly stated that different types of organisms would be expected to differ in their ability to survive, depending on the traits they possessed. Therefore, there could be natural selection among forms.

(1792-1876): German biologist and scientific explorer. One of the founders of embryology, von Baer discovered the notochord and the embryonic blastula. In 1817, von Baer became a professor at Königsberg University One of the founders of embryology, von Baer discovered the notochord and the embryonic blastula. He also established the fact that mammals develop from eggs. Together with Heinz Christian Pander, he proposed the now accepted germ layer theory of development, in which three distinct systems of bodily structures are derived from three distinct layers of cells in the embryo, the ectoderm,mesoderm, and endoderm. n addition to his work in comparative anatomy and embryology, Von Baer made important contributions to arctic biology, meteorology, geology, and geography.

(1938-). American biologist. Shared the 1975 Nobel Prize in Physiology or Medicine with Howard Temin and Renato Dulbecco for their discovery of reverse transcriptase.

(1909-1975). American geneticist. By means of x-ray irradiation of the mold Neurospora crassa and screening of the resulting mutants, Beadle showed, with Edward Tatum, that mutations induced in genes corresponded to alterations in specific enzymes. This finding led to the acceptance of the one gene/one enzyme hypothesis. Shared with Tatum half the 1958 Nobel Prize in Physiology or Medicine.

(1905-2002). Austro-Hungarian-born American biochemist whose experiments provided crucial information allowing Watson, Crick, and Wilkins to elucidate the double-helix structure of DNA. Chargaff received a doctorate in chemistry from the Vienna University of Technology (Technische Universität Wien) in 1928. After graduation he went on to Yale University in the United States, where he investigated the chemical composition of lipids in Mycobacterium tuberculosis, the bacterium causing tuberculosis. After a brief stint at the Pasteur Institute, he went back to the United States, and in 1935 started a lifelong career at Columbia University, New York. Chargaff became a U.S. citizen in 1940. He had a wife, Vera Broido—they he married in 1928.

(1769-1832). French naturalist and zoologist. Founder of the fields of vertebrate paleontologyand comparative anatomy. One of the most prolific authors of scientific literature in the history of biology. Cuvier's "contributions to science are almost too extensive to be listed." By showing that the remains of huge animals such as woolly mammoths and giant ground sloths were distinct from those of any living animal, Cuvier established extinction as a fact. Such creatures, he pointed out, would be far too large to overlook if they still existed. His two papers on these animals, landmarks in the history of paleontology, both appeared in 1796 when he was just 27 years old. At the time, it was still generally believed that no animal had ever gone extinct.

(1893-1988). Pioneering paleoanthropologist. Discoverer of the Taung Child. He was the first scientist to provide hard evidence that humans first evolved in Africa.  In 1924, he found himself examining fossil-bearing rocks blasted from a limestone quarry at Taung, a small town situated in the North West Province of South Africa. Among them he found a skullcap, to his anatomist's eye obviously that of a primate. It fit precisely over a brain-cast protruding from the surface of one of the rocks. After more than a month of patient chipping, he managed to reveal the skull's face. It was the first specimen of an australopithecine ever found.

(1809-1882). English naturalist. One of the most famous scientists who ever lived. His book, On the Origin of Species, convinced many of the reality of evolution. Remembered for the theory of natural selection, the credit for which he had to share with Alfred Wallace, who formulated it independently.

(1848-1935). The most influential post-Darwinian saltationist up to the time of Eldredge and Gould, de Vries dominated evolutionary thought during the the early twentieth century.

(1878-1958) German-born American geneticist. First biologist to integrate genetics, development, and evolution. Although one of the most prominent geneticists of his era, Goldschmidt was rejected by his colleagues when he proposed a saltational theory of evolution..

(1941-2002). American paleontologist, who, along with Niles Elredge, revived the saltationist tradition in biology by pointing out that the typical fossil form comes into being rapidly and remains largely the same thereafter, right up to the time of extinction ("punctuated equilibrium").

(1730-1799). Dutch-born physician, chemist, and plant physiologist. Showed light is essential to plant respiration and that the gas plants produce in light is oxygen. He is therefore recognized as the discoverer of photosynthesis. Showed light is essential to plant respiration and further demonstrated that the gas released by plants is oxygen.

(1744-1829). Early evolutionary theorist. Long before Darwin, Lamarck proposed that human beings had evolved from apes. Chief founder of the field ofinvertebrate paleontology. Early evolutionary theorist.

(1707-1778). Swedish botanist, zoologist, and taxonomist. Creator of the modern system of scientific nomenclature. Early evolutionary theorist. Established conventions for naming living organisms still in general scientific use today—in particular, he popularized binomial nomenclature, which had first been by developed by the Bauhin brothers (Gaspard and Johann Bauhin) more than a century before. He was the first to use binomial names consistently. As a young man Linnaeus was a creationist, but he later developed an evolutionary theory of his own.

(1822-1884). Austrian scientist/monk. Showed inheritance of traits follows particular rules, now known as Mendel's Laws. In an fascinating, original article, guest author David Allen, discusses Mendel's hybridization research, and how it has been misrepresented at times by both sides of the modern debate between Darwinians and creationists.

(1866-1945). American geneticist. Elucidated the connection between meiosis and genetic segregation. His discoveries about genes and their locations on chromosomes helped make biology into an experimental science. Nobel Prize in Physiology or Medicine (1933).

(23-79 AD). Ancient Roman naturalist, also known as Gaius Plinius Secundus or Caius Plinius Secundus. Pliny's only surviving work, his great Natural History, covers nearly the entire field of ancient knowledge about the natural world.

(1909-1975). American geneticist. By means of x-ray irradiation of the mold Neurospora crassa and screening of the resulting mutants, Tatum showed, with George Beadle, that mutations induced in genes corresponded to alterations in specific enzymes. This finding led to the acceptance of the one gene/one enzyme hypothesis. Shared with Beadle half of the 1958 Nobel Prize in Physiology or Medicine

(1514-1564). The founder of modern human anatomy. Born in Brussels near a hill where condemned criminals were tortured, executed, and left to rot, Vesalius must have been familiar with the details of human anatomy even as a child. As a medical professor, he went on to make the acquaintance intimate by handling and dissecting the bodies himself — this had been the job of underling barber-surgeons up to that time. Though bodies were in short supply, he used every means legal, and sometimes, illegal to get the materials he needed for his studies. In his memoirs he recalls forays by night to search the stakes and gibbets for classroom materials. His gristly habits paid off. Unlike his predecessors, Vesalius' drawings were based on direct observation. He transformed his field of research and forever changed the teaching of medicine. Vesalius' masterwork, De humani corporis fabrica(On the Fabric of the Human Body, 1543, 1555), remained the basis of medical illustration for generations and still influences how we look at our bodies today.

(1823-1913). British naturalist. Developed the theory of natural selection independently of Charles Darwin. One of the most creative, adventurous, and amiable biologists of the 19th century. Wallace went on to explore the Rio Negro, a major river deep in the western Amazon Basin. There he collected specimens of the flora and fauna, gathered information about the indigenous peoples, and made notes on the geography. In the summer of 1852, he tried to return to England with everything he had collected on his inland expedition, but a month into the voyage his ship caught fire. Wallace escaped with the crew, spending ten days at sea in a lifeboat, but nearly all his specimens and most of his notes went down with the ship. Fortunately, he had insurance and was at least compensated financially for his loss. He also had many specimens to sell that he had shipped home separately before he left Belem for the Rio Negro.