From anatomy to systematic taxonomy (1516–1565). His is considered the beginning of modern zoology. The
Renaissance was the age of collectors and travellers, when many of the stories were actually demonstrated as true when the living or preserved specimens were brought to Europe. Verification by collecting of things, instead of the accumulation of anecdotes, then became more common, and scholars developed a new faculty of careful observation. The Renaissance brought expanded interest in both empirical natural history and physiology. In 1543,
Andreas Vesalius inaugurated the modern era of Western medicine with his seminal
human anatomy treatise
De humani corporis fabrica, which was based on dissection of corpses. Vesalius was the first in a series of anatomists who gradually replaced
scholasticism with
empiricism in physiology and medicine, relying on first-hand experience rather than authority and abstract reasoning.
Bestiaries—a genre that combines both the natural and figurative knowledge of animals—also became more sophisticated.
Conrad Gessner's great zoological work,
Historiae animalium, appeared in four volumes, 1551–1558, at Zürich, a fifth being issued in 1587. His works were the starting-point of modern zoology. Other major works were produced by
William Turner,
Pierre Belon,
Guillaume Rondelet, and
Ulisse Aldrovandi. Artists such as
Albrecht Dürer and
Leonardo da Vinci, often working with naturalists, were also interested in the bodies of animals and humans, studying physiology in detail and contributing to the growth of anatomical knowledge. In the 17th century, the enthusiasts of the new sciences, the investigators of nature by means of observation and experiment, banded themselves into academies or societies for mutual support and discourse. The first founded of surviving European academies, the
Academia Naturae Curiosorum (1651) especially confined itself to the description and illustration of the structure of plants and animals; eleven years later (1662) the
Royal Society of London was incorporated by
royal charter, having existed without a name or fixed organisation for seventeen years previously (from 1645). A little later the
Academy of Sciences of
Paris was established by
Louis XIV, While Linnaeus conceived of species as unchanging parts of a designed hierarchy, the other great naturalist of the 18th century,
Georges-Louis Leclerc, Comte de Buffon, treated species as artificial categories and living forms as malleable—even suggesting the possibility of
common descent. Though he was writing in an era before evolution was recognized, Buffon is a key figure in the
history of evolutionary thought; his "transformist" theory would influence the evolutionary theories of both
Jean-Baptiste Lamarck and
Charles Darwin. Before the
Age of Exploration, naturalists had little idea of the sheer scale of biological diversity. The discovery and description of new species and the collection of specimens became a passion of scientific gentlemen and a lucrative enterprise for entrepreneurs; many naturalists traveled the globe in search of scientific knowledge and adventure. '' (1735) Extending the work of Vesalius into experiments on still living bodies (of both humans and animals),
William Harvey investigated the roles of blood, veins and arteries. Harvey's
De motu cordis in 1628 was the beginning of the end for Galenic theory, and alongside
Santorio Santorio's studies of metabolism, it served as an influential model of quantitative approaches to physiology.
Impact of the microscope In the early 17th century, the micro-world of zoology was just beginning to open up. A few lensmakers and natural philosophers had been creating crude
microscopes since the late 16th century, and
Robert Hooke published the seminal
Micrographia based on observations with his own compound microscope in 1665. But it was not until
Antony van Leeuwenhoek's dramatic improvements in lensmaking beginning in the 1670s—ultimately producing up to 200-fold magnification with a single lens—that scholars discovered
spermatozoa,
bacteria,
infusoria and the sheer strangeness and diversity of microscopic life. Similar investigations by
Jan Swammerdam led to new interest in
entomology and built the basic techniques of microscopic dissection and
staining. Debate over the
flood described in the Bible catalyzed the development of
paleontology; in 1669
Nicholas Steno published an essay on how the remains of living organisms could be trapped in layers of sediment and mineralized to produce
fossils. Although Steno's ideas about fossilization were well known and much debated among natural philosophers, an organic origin for all fossils would not be accepted by all naturalists until the end of the 18th century due to philosophical and theological debate about issues such as the age of the earth and
extinction. ,
Paris Advances in
microscopy also had a profound impact on biological thinking. In the early 19th century, a number of biologists pointed to the central importance of the
cell. In 1838 and 1839,
Schleiden and
Schwann began promoting the ideas that (1) the basic unit of organisms is the cell and (2) that individual cells have all the characteristics of
life, though they opposed the idea that (3) all cells come from the division of other cells. Thanks to the work of
Robert Remak and
Rudolf Virchow, however, by the 1860s most biologists accepted all three tenets of what came to be known as
cell theory. ==In advance of
On the Origin of Species==