Science Timeline

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Below is a list of historical figures and events that have made major impacts on the development of science. Each is listed in chronological order by the date of a major publication or discovery. More detailed timelines are available for each section.

Contents

[edit] Ancient Science

See Ancient Science for a more detailed timeline of the history of science in Classical Antiquity.

Evidence of medical practice predates human history. Some of the first Neanderthal skeletons reveal healed fractures, advanced arthritis and jaws remodeled after losing teeth — all suggesting these early humans cared for the weaker members of their group. Human skulls more than 10,000 years old show evidence of healing after surgical incision (trepanation). By the time of ancient Egypt, hundreds of human diseases are documented in what is now known as the Edwin Smith papyrus. The practice of mummifying the dead reveals some knowledge of anatomy, as different organs are removed for separate preservation in Canopic jars.

Western medicine is separated from religion in ancient Greece by Hippocrates, who produces the first scientific theory of disease based on natural causes. Herophilus, the first scientific anatomist, performs human dissections and names anatomical structures systematically. Human dissection is no longer practiced in the Roman empire, when Galen uses animal dissection to expand anatomical knowledge. This leads, inevitably, to errors which are left uncorrected for over a thousand years as science enters the Dark Ages.

Prehistory
The art of healing was practiced even in prehistoric times. Numerous human remains show evidence of chronic debilitating diseases indicating that early people cared for each other.
Bronze Age
As agriculture creates a need for record-keeping, medical knowledge that passed from generation to generation begins to be written down in the early civilizations of the Near East, Asia, and the Americas.
Classical Antiquity
Hippocrates distinguishes medicine from religion, asserting that diseases have natural causes. The balance of the "four humors" (blood, phlegm, yellow bile, and black bile) forms the basis for the humoral theory of medicine that persists unchallenged in the West for over 2000 years.
Christian Era
Galen, the most important experimentalist of medical history until the 17th century, summarizes the extent of medical knowledge just as the classical era of scientific investigation comes to an end. His authority remains unchallenged, and his errors go undetected, for nearly 1500 years.

[edit] Medieval Science

See Medieval Science for a more detailed timeline of the history of science in the Middle Ages.

By the 9th century, ancient Greek texts are translated into Arabic, a crucial step in the advancement of medical knowledge in the Arab world. During this time, Latin expands from religious use to become the dominant language of academic communication in Europe. Ancient texts on astronomy, mathematics, and medicine are translated into Latin from Arabic and, later, from the original Greek when these are discovered. The names of many Muslim scientists are also Latinized, such as Avicenna (ibn Sina), whose Canon of Medicine will remain a standard textbook until the 18th century. By then, Western science begins to expand on ancient knowledge and the practice of Latinizing scientific names falls into decline. In the 21st century, however, Latin remains a source for new vocabulary words needed to keep up with the pace of discovery in biology and medicine.

The death of millions of Europeans, during the Black Plague of the 14th century, shatters pre-existing ideas about life and medical authority. This event, along with the arrival of medical textbooks translated into Latin, sets the stage for the Renaissance in Western thought.

Islamic Golden Age
After the fall of Rome, patients seek treatment in monasteries and Western medicine returns to the control of religious authority. Arab physicians preserve and extend ancient science, bringing the practice of surgery and chemistry to a much higher level.
European Middle Ages
Classical medicine is retranslated from Arabic and Greek into Latin, which remains the source for new biomedical vocabulary into the 21st century. Ancient medicine is first studied at the medical school of Salerno, whose students go on to revive medical learning across Europe.

[edit] The Scientific Revolution

See the Scientific Revolution for a more detailed timeline of the history of science in the 16th and 17th centuries.

The practice of human dissection returns to Europe in 14th century Italy, but its purpose is mainly to confirm ancient observations. Although Leonardo da Vinci performs careful dissections and illustrates the human body with unprecedented accuracy, none of his work is published until many centuries later. Andreas Vesalius is the first to publicly break with tradition and describe human anatomy using observations from his own dissections. This revolutionizes medicine and brings it into the current era, where experimental evidence trumps the opinions of authority figures.

The Renaissance
Italy's ports welcome new ideas from the East and are also hit hardest by the Black Death (bubonic plague), resulting in waves of complex social change that will become known as the Renaissance. Classical ideas are reexamined as empirical science takes hold in astronomy and anatomy.
The Age of Exploration
Knowledge of new cultures and whole continents is gained when Columbus reaches the Americas in 1492. The exchange transmits diseases such as smallpox to North America and syphilis is brought to Europe. The practice of tobacco smoking is also adopted in Europe.
The Scientific Revolution
William Harvey solves the mystery of blood circulation as a new system of physiology, based on quantitative measurement, joins descriptive anatomy in the construction of a scientific basis for medical practice.

[edit] The Age of Enlightenment

See Enlightenment Science for a more detailed timeline of the history of science in the 17th and 18th centuries.

In 17th century astronomy, the telescope enables new observations about very large objects in the solar system. The microscope performs a similar function in the history of biology, allowing observations of very small structures for the first time. Robert Hooke observes the structure of cork with a compound microscope and names the chambers he sees cells. Hooke also observes live plant cells with a compound microscope and studies artificial ventilation (keeping a dog alive by blowing air into its lungs with a bellows). Marcello Malpighi discovers capillaries in the lung of a frog, confirming the new theory by William Harvey that blood circulates in a closed system. Anton van Leeuwenhoek discovers a diversity of microbial life forms and is the first to describe the structure of human sperm. Also during this time, Regnier de Graaf describes follicles in the mammalian ovary, which he believes to be eggs. Global travel becomes possible with the discovery, by James Lind, that fresh fruit staves off the disease of scurvy during long sea voyages. Lind uses the first controlled clinical trial to answer a medical question and his recommendations pave the way for expansion of the British Empire. Carolus Linnaeus develops a system of biological classification that brings order to the many new species of plants and animals being discovered around the world. Diseases are classified systematically by Giovanni Morgagni, who correlates extensive autopsy evidence with the clinical observations of diseases made when the patient was alive. The most famous medical breakthrough in the 18th century is the development, by Edward Jenner, of a vaccine that prevents smallpox using a live virus that causes a similar disease in cows.

Microscopists
The microscope, a gift of applied physics, opens up a world of previously unknown microscopic life. The discovery of cells and tissues allow for greater understanding of health and disease.
The Enlightenment from 1700
Political stability in Europe fosters an age of exploration and Enlightenment. Iatrophysics, the medical applications of physics, include early investigations in hydrodynamics, air pressure, and electricity.
Encyclopedists from 1750
During the Enlightenment, scientists organize knowledge systematically. Inspired by the Linnaean system for classifying organisms, Morgagni correlates disease symptoms with anatomical pathology, while Haller writes the first systematic encyclopedia of normal physiology.

[edit] 19th Century Science

See 19th Century Science for a more detailed timeline of the history of science during this era.

Two major innovations in biological thought occur in the 19th century. With the first artificial synthesis of an organic molecule in 1828, a debate ensues over whether biological processes can occur outside of cells. Louis Pasteur, who studies the growth of bacteria in wine, proposes vitalism (that living processes can only be observed in vivo) while early biochemists resist the idea and study enzyme catalyzed reactions in vitro. One benefit of this debate is the demolition of the idea of spontaneous generation and the development of the germ theory of disease, leading to improved antiseptic procedures in medicine and surgery.

While the cell theory is established through numerous observations of the microscopic world, naturalists such as Charles Darwin begin to compile their observations of the natural world. These are crucial for the development of Darwin's theory of evolution by natural selection — the most important legacy of this era. The genetic studies of Gregor Mendel, which will be essential for providing the mechanism for natural selection, remain unknown until the 20th century.

With the explosion of scientific knowledge, numerous scientific subspecialties appear and science becomes a paid profession during the 19th century. The modern research-based university system is established, centered in Germany during this time.

Professional Specialization from 1800
New elements are discovered as chemists analyze the compositions of compounds. Histology analyzes the composition of human organs into tissues. Research in embryology brings about the collapse of the theory of preformation in human development. The concept of evolution by natural selection has enormous explanatory power and becomes biology's most important idea.
Public Health Reforms from 1850
The germ theory of disease brings an end to ideas about spontaneous generation as surgery is made safer through the use of antisepsis and anesthesia. The discovery of x-rays has immediate applications in medicine as views of the human body become forever altered by new technology.

[edit] Modern Science

See Modern Science for a more detailed timeline of the history of modern science.

In the 20th century, science becomes even more subspecialized and research becomes more expensive to conduct. Government funding aims to expand scientific knowledge even further. The most important contribution to biology is the synthesis of evolutionary theory and genetics, leading to the new science of molecular biology. Thomas Hunt Morgan constructs the first genetic maps of chromosomes, using the fruit fly as an experimental animal. Once DNA is proven to be the molecule that carries genetic information, its structure is soon elucidated by James Watson and Francis Crick. This leads to the discovery of the genetic code and, ultimately, to the decoding of the entire human genome by century's end.

With the discovery of new vaccines, insulin, and antibiotics (especially pencillin by Alexander Fleming) medicine becomes widely effective for the first time in human history. However the discovery, by molecular biologists Salvador Edward Luria and Max Delbrück, that bacteria can evolve rapidly by exchanging genes with each other presaged the era of antibiotic resistant organisms. Smallpox becomes the first disease in human history ever to be eradicated — nearly two centuries after the discovery of vaccination. This is contrasted sharply by the eradication of SARS, a global epidemic whose virus has been discovered, decoded, and eradicated all within two years. While the molecular mechanisms of cancer and AIDS are slowly being revealed, scientists hope for more cures in the century to come.

Modern Synthesis from 1900
The rediscovery of Mendelian genetics stimulates research into the chemical basis of heredity. Molecular biologists use viruses to probe the structure of proteins and nucleic acids, as DNA is confirmed as the genetic material.
Molecular Medicine from 1950
The discovery of hormones, neurotransmitters, vitamins, and especially antibiotics make medical care, for the first time in history, more beneficial than harmful. The discovery of the genetic code stimulates the sequencing of complete genomes as medicine enters a new molecular era.
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