100 Greatest Discoveries - BIOLOGY
1. Microorganisms (1674)
Microscope lens grinder Anton Van Leeuwenhoek accidentally discovers microorganisms in a drop of water. Using his own microscopes, he observes sperm, bacteria and red blood cells. His observations lay the foundation for the sciences of bacteriology and microbiology.
2. The Cell Nucleus (1831)
While studying an orchid, botanist Robert Brown identifies a structure within the cells that he terms the "nucleus."
3. Archaea (1977)
Carl Woese discovers bacteria are not the only simple-celled prokaryotes (unicellular organisms without a nucleus) on Earth. Many of the organisms classified in the new kingdom of Archaea are extremophiles. Some live at very high or low temperatures, others in highly saline, acidic or alkaline water. Some have been found in environments like marshland, sewage and soil. Archaea are usually harmless to other organisms and none are known to cause disease.
4. Cell Division (1879)
Walther Flemming carefully observes that animal cells divide in stages and calls the process mitosis. Eduard Strasburger independently identifies a similar process of cellular division in plant cells.
5. Sex Cells (1884)
August Weismann identifies that sex cells must have divided differently to end up with only half of a chromosomal set. This very special division of sex cells is called meiosis. Weismann's experiments with reproduction in jellyfish lead him to the conclusion that variations in offspring result from the union of a substance from the parents. He refers to this substance as "germ plasm."
6. Cell Differentiation (late 19th century)
Several scientists participate in the discovery of cell differentiation, eventually leading to the isolation of human embryonic stem cells. During differentiation, a cell turns into one of the many cell types that make up the body, such as a lung, skin or muscle cell. Certain genes are activated and others are inactivated, so the cell develops structures to perform a specific function. Cells that are not yet differentiated and have the potential to become any type of cell are called stem cells.
7. Mitochondria (late 19th century to the present)
Scientists discover mitochondria, the powerhouses of the cell. These small structures within animal cells are responsible for metabolism and convert food into chemicals that cells can use. Originally thought to be part of the cell, scientists now believe they are specialized bacteria with their own DNA.
8. The Krebs Cycle (1937)
Hans Krebs identifies the many steps the cell takes to convert sugars, fats and proteins into energy. Also known as the citric acid cycle, it is a series of chemical reactions using oxygen as part of cellular respiration. The cycle contributes to the breakdown of carbohydrates, fats and proteins into carbon dioxide and water.
9. Neurotransmission (late 19th to early 20th century)
Scientists discover neurotransmitters and how they tell the body what to do by passing signals from one nerve cell to another via chemical substances or electrical signals.
10. Hormones (1903)
William H. Bayliss and Ernest H. Starling give hormones their name and reveal their role as chemical messengers. The team specifically describes secretin, a substance released into the blood from the duodenum (between the stomach and small intestine) that stimulates secretion of pancreatic digestive juice into the intestine.
11. Photosynthesis (1770s)
Jan Ingenhousz discovers that plants react to sunlight differently than shade. The underpinnings of the understanding of photosynthesis are born. Photosynthesis is a process in which plants, algae and certain bacteria convert the energy of light into chemical energy. In plants, leaves take in carbon dioxide and roots absorb water. Sunlight runs a reaction that yields glucose (food for the plant) and oxygen (a waste product released into the environment). Nearly all living things on Earth are ultimately dependent on this process.
12. Ecosystem (1935)
Arthur George Tansley coins the term ecosystem and single-handedly bridges the biology in ecology with the physics, chemistry and other fields of science that describe the environment. An ecosystem is defined as a dynamic and complex whole that functions as an ecological unit.
13. Tropical Biodiversity (15th century to the present)
On sailing expeditions around the world, early European explorers notice that the tropics host a much greater variety of species. Answering why this is the case allows today's scientists to help protect life on Earth.
100 GREATEST DISCOVERIES (2004)
by Discovery Channel
Scientists have transformed the way we think and live throughout the centuries. What are the most important scientific discoveries of all time? In no particular order, we present the top 100 in eight different categories:
Bill Nye "The Science Guy" hosts a new series that highlights the greatest scientific discoveries of all time, from the earliest time to the present day. The series features nine episodes: Evolution, Earth Sciences, Medicine, Physics, Astronomy, Chemistry, Genetics and Biology, plus a wrap up episode featuring the top 10 discoveries of all time. This is a fun and instructive series, with a lot of historical re-creations, archival footage, visits to interesting scientific research facilities and interviews with present-day scientists including several Nobel laureates - all presented with the flair and humor associated with television's "Science Guy" Bill Nye.
Kathryn Coombs/ imdb.com
Product Description, by Amazon.com
Join host Bill Nye as he recounts the 100 most important discoveries and explains how each one has had a hand in shaping the modern world. Evolution & Earth Sciences: From the discovery of the dinosaur-killing KT asteroid to Carl Linnaeus' still-used life form classification system to the groundbreaking theories of Charles Darwin, learn how intelligent life began on earth. Venture beneath our planet's crust for a look at the powerful geological forces that keep life on the move and adapting plate tectonics, earthquakes and super volcanoes. Medicine & Physics: With physician Andreas Vesalius's groundbreaking anatomical drawings in 1538, a new science was born. Witness the horror of a pre-anesthesia operating room, see how X-rays were discovered and meet the man who developed the first vitamin. Plus, learn how physicist Sir Isaac Newton developed his three laws of motion and travel inside the atom for an explosive look at Einstein's best-known theory. Astronomy & Chemistry: Copernicus first theorized that the Sun was the center of our solar system, but it took the work of Johannes Kepler to prove it. Learn why the universe is expanding and meet modern astronomers who gauge the likelihood of life "out there." Joesph Priestley initiated the study of chemistry in 1770 with the discovery of oxygen. Genetics & Biology: Gregor Mendel's work with pea plants pioneered the study of genetics, but it wasn't until the creation of the double helix DNA model that the field really began to take off. Hundreds of years before the first DNA test, "Micrographia" championed the use of microscopes and set the stage for the first major discovery in biology: microorganisms. Learn how the secret of the cell was solved and how starfish led to the development of stem cell research. Top Ten Discoveries: What are the 10 greatest scientific discoveries of all time? Find out which of the original 100 were voted by viewers as the most groundbreaking.