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300
Xenophanes
Xenophanes basically traced the origin of humans back to the transitional period between the fluid stage of the earth and the formation of land. He also held to a spontaneous generation of fully formed plants. -
300
Anaximenes
Anaxiemens thought that air was the element thatimparted life, motion and thought. He also though that there was a primordial terrestrial slime, a mixture of earth and water, which when combined with the sun's heat formed plants, animals and human beings directly. -
Oct 10, 1255
Medevil Church
In 1255, the medevil church accepted spontaneous generation and said that it was all done by angels acting through the agency of the sun. -
Jan Baptist van Helmont
This scientist experimented by growing a willow for five years and showing it increased mass while the soil showed a trivial decrease in comparison. At this time photosynthesis was not understood so he contributed the increase of mass to the absorption of water. -
William Harvey
Harvey dissected deer and showed that there was no visible embryo during the first month of pregancy. Because there was no microscope at the time, he thought that it was made from invisible babies. 1635 -
Redi's Experiment
An italian scientest named Facesco Redi desgineda scientific experiment to test the spontaneous creation of maggots. He placed fresh meat in one jar that was left open; the other was covered by cloth. A few days later the jar that was open ad maggots in but the covered on didnt have any, they were just on the surface of the cloth. He demonstrated that the maggots came fro mfly eggs and that helped to prove spontaneous generation wrong. -
Needham proves Redi wrong
John Needham proved Redi's theory wrong. He placed gravy into a bottle and then heated the bottle in order to kill anything that was inside, then sealed it. A few days later he reported that there was life in the broth and said that the life had been created from nonlife. Really, he didn't heat the gravy long enough to kill all of the microbes. -
Microscope
John Yarwell created the microscope -
Spallanzani's Experiment
Another italian scientest named Lazzaro Spallanzani concluded that Naadham's heating of the bottle didn't really kill all the microbes and things inside. He constrructed his own experiment. First he placed broth in each of the two seperate bottles, boiled both, sealed one and left the other open. A few days later, the unsealed bottle was teeming with small living things and he could see these things because of the microscope. He concluded that air was needed for Spontaneous Generation. -
Pasteur's Experiment
Pasteur decided that he wanted to recreate the experiment again. He designed bottles with S-curved necks that were oriented downward to prevent access by airbone materials. He reasoned that the contamination came from life-forms in the air. Pasteur finally convinced the learned world that even if exposed to air, life did not arise from nonlife. -
Spontaneous Generation is "born"
Aristotle argues that spontaneous generation is on of the four means of reproduction in 400 BC.