-
900 BCE
Creationist
God created everything. -
350 BCE
Spontaneous Generation
This theory comes from the Greeks, especially Aristotle, is the thought on the ordinary formation of living organisms without descent from similar organisms. -
Biogenesis
Francesco Redi, an italian scientist proposed an alternative for the Spontaneous Generation. -
Change through use and disuse: Lamarck
When environments changed, organisms had to change their behavior to survive. If they began to use an organ more than they had in the past, it would increase in its lifetime. If a giraffe stretched its neck for leaves, for example, a "nervous fluid" would flow into its neck and make it longer. -
The theory of evolution by natural selection: Darwin
Organisms change over time as a result of changes in physical or behavioral traits. Changes that allow an organism to better adapt to its environment and will help it survive. -
Endosymbiotic
Russian botanist Konstantin Mereschkowski said that larger, more complex cells evolved from the symbiotic relationship between less complex ones. -
Panspermia
Swedish chemist Svante Arrhenius specified that can be said to be either interstellar or interplanetary transport mechanisms may include comets, radiation pressure and lithopanspermia (microorganisms embedded in rocks). -
Physical-Chemical
Alexander I. Oparin was a Soviet biochemist that talked about organisms created in a primitive atmosphere. -
CONCLUSION
My point of view of all of this theories is that with the time, and the creation of new technologies, scientists have been developing more complex proposals of the origin of life. And I also think that this chain of development will continue for the next years, always finding new things that will bring more and more questions.