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Theory of Creationism (James Ussher, Gregor Cuvier)
It established the hypothesis of a divine creation of infinite life forms that interact with each other and had remained unchanged since its creation.
The Irish Archbishop Ussher finalized the exact date of this creation based on the biblical writings, 23 October 4004 BC.
It was concreted as a theory at mid-XVIII century thorugh a play of Karl von Linneo. -
Theory of Uniformism (James Hutton, Lyell)
In the 1790s, Hutton had stated that the Earth was transformed by unimaginable catastrophes, but by imperceptibly slow changes, many of which we see around us today. He said that the Earth was enormously old, like a perpetual motion machine that passed through regular cycles of destruction and rebuilding that made the planet was suitable for mankind. Lyell's version of geology became known as uniformism, because of its insistence that the processes that alter the Earth are uniform over time. -
Theory of Transformism (Jean-Baptiste Lamarck)
- Use and disuse of parts
If a body part is used, it quickly grows and develops, while the parts that are not used, atrophy and may disappear. - Inheritance of acquired characters
Any animal can transmit to their descendants those characteristics it has acquired along his life.
- Use and disuse of parts
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Theory of Catastrophism (George Cuvier)
It established a geological history punctuated by catastrophes. In such periods would have produced the extinction of species that existed and their replacement by others. These new species would come from other regions of the planet that would have been saved from disaster.
We can't know exactly the year in which the theory was proposed, but in 1821, Cuvier published his play "Théorie de la terre". -
Theory of Charles Darwin - Alfred Wallace
- The high reproductive capacity of living beings. They noticed it was very common that species produce many more offspring than probably would arrive to adulthood.
- The variability of the offspring. The descendants of a pair are not identical. Many of the differences would haven't great importance, but others could be essential. Most occurs randomly and is the result of combining the genes of the parents.
- The performance of natural selection. Only the best adaptated species would survive.
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Refutation of Spontaneous Generation Theory (Louis Pasteur)
Established that could arise complex, animal and plant life spontaneously from nonliving matter.
This idea appeared long ago, thanks mainly to Aristoteles, but nobody has never officially proposed.
There have been experiments of Redi (1665) and Spallanzani showed that there was no spontaneous generation, but failed to completely eliminate the theory.
In 1859, Louis Pasteur disproved the theory by a simple experiment and showed that living things come only from other living beings predecessors -
Theory of Panspermia (Svante Arrhenius)
In the nineteenth century, Hermann Richter thought the Earth was impregnated by cosmozoarios that were on solid particles and hidden in meteorites, they would arrive to planetary bodies and would develop. Arrhenius elaborated this theory from Ritcher's idea.
It establish that life came to Earth in the form of bacterial spores from space and driven by the radiation pressure of the stars. -
Theory of the chemical evolution (Oparin-Haldane)
Oparin established, thanks to the energy provided primarily by ultraviolet radiation from the sun and the electric shock of the constant storms, small molecules of atmospheric gases (H2O, CO2, H2S, CH4, NH3) resulted in prebiotic molecules . These increasingly complex molecules are amino acids and nucleic acids.
According to Oparin, these first molecules would be trapped in shallow water ponds formed in the primitive ocean coastline. By concentrating, continued to evolve and diversify. -
Theory of Neodarwinism (Dobzhansky-Mayr-Simpson)
It mainly consists of Darwinism enrichment due to new discoveries in genetics.
According to the synthetic theory, the mechanisms of evolution are:
- Natural selection, as in Darwin's theory.
- The mutations or random changes in the genetic structure of organisms.
- Genetic drift: random process by which over several generations the genetic population structure changes.
- Gene flow: process by which populations become genetically homogeneous.
This theory is the most accepted by scientists -
Theory of neutralism, Motoo Kimura
This theory of molecular evolution states that most mutant genes are selectively neutral, that is, not selectively have more or less advantage than genes to be replaced. At the molecular level, most evolutionary change is due to genetic drift of selectively equivalent mutant genes. -
Theory of punctuated equilibrium, Gould - Eldredge
Gould said that evolution is not a constant gradual process, but the species alternate long periods of stability in which no changes occur, with brief periods in rapidly changing.
