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300 BCE
Greek philosopher Aristotle
was one of the earliest recorded scholars to articulate the theory of spontaneous generation.Aristotle proposed that life arose from nonliving material if the material contained pneuma (“vital heat”) -
The Compound microscope was Created
Hans Lippershey and his son, Zaccharias Hanssenhad discovered that an image magnified by a single lens can be further magnified by a second or more lenses. discovering the compound microscope -
The first Microscope is created
lens grinders Hans and Zacharias Janssen make the first microscope by placing two lenses in a tube. -
The first person to discover cells
Robert Hooke was the first person to view and describe cells He examined a piece of cork using a primitive microscope. He saw tiny boxes while examining the cork which he thought looked like small rooms, this led him to calling them cells. -
Francesco Redi tries to prove spontaneous generation with his meat experiment
Redi set up a series of flasks containing different meats, half of the flasks sealed, half open. He then repeated the experiment but, instead of sealing the flasks, covered half of them with gauze so that air could enter. He found the flask that were open had flies in them. The open flask contained maggots so Redi said no to spontaneous generation -
The first person to describe cells
Anton van Leeuwenhoek Looked through a pond with a powerful microscope and saw tiny organisms in the pond of water also looked at other samples and saw single celled organisms that he named animalcules. This is the first time scientist could see microscopic living things. He was also the first person to describe cells and bacteria -
Charles Hall invented the achromatic lens
By using a second lens of different shape and refracting properties, he could realign colors with minimal impact on the magnification of the first lens. -
John Needham challenges Redi's findings
he placed a broth into a bottle, heated the bottle to kill anything inside, then sealed it. Days later he found out a presents of life in the bottles and announced life came from non life. -
Lazzaro Spallanzani disproves spontaneous generation
Lazzaro does an experiment placing broth in each of two separate bottles, boiling the broth in both bottles, then sealing one bottle and leaving the other open. Days later the contain that was open had life in it while the sealed one had no sources of life. -
Upgrades to the Microscope
Several technical innovations make microscopes better and easier to handle, which leads to more and more people using them, they are more scientists.important discovery is that lenses combining two types of glass could reduce the chromatic effect. -
The begining of cell theory
two German biologists named Matthias Schleiden and Theodor Schwann studied plant and animal cells . Through their studies, they concluded that all living things were made up of cells and that a cell is the smallest unit of organization in a living thing. The basis of cell theory. -
Another key component to cell theory
Rudolf Virchow studied cellular pathology and proposed that all cells come from other cells. Rudolf and a bunch of other scientist did testing to shoe cells do not appear spontaneously. There testing explained how things grow and reproduce a key factor to cell theory -
Louis Pasteur disproves Spontaneous Generation
Pasteur did an experiment with a flask that was the shape of an s. He put a nutrient rich broth in the flask. He then boiled the broth killing any microorganisms which were already present. Then he allowed the infusion to sit. Because of the shape of flask air was exposed to the broth. No matter how long the flask stayed there , microorganisms never appeared in the broth. -
the Abbe condenser
made possible the development of a new range of seventeen microscope objectives. -
Richard Zsigmondy develops a new microscope
Richard Zsigmondy develops a new microscope that can study objects below the wavelength of light -
Frits Zernike invents the phase-contrast microscope
Frits Zernike invents the phase-contrast microscope that allows the study of colorless and transparent biological materials. -
Ernst Ruska develops the electron microscope
The ability to use electrons in microscopy greatly improves the resolution -
Miller and Urey's experiment
They conducted an experiment which demonstrated that several organic compounds could be formed spontaneously by simulating the conditions of Earth's early atmosphere. Those Compounds are water (H2O), methane (CH4), ammonia (NH3) and hydrogen (H2) -
Lynn Margulis first made the case for endosymbiosis
She proposed that t cell organelles such as mitochondria and chloroplasts were once independent bacteria Nobody believed her at first -
Gerd Binnig and Heinrich Rohrer invent the scanning tunneling microscope
three-dimensional images of objects down to the atomic level. -
The invention of the digital Microscope
Digital microscopes allow for live image transmission to a TV or computer screen and have helped revolutionize microphotography.
