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THE ORIGIN OF LIFE, pateur, redis-experiment - Coggle Diagram
THE ORIGIN OF LIFE
The problem of spontaneous generation
People belived that living things were generated spontaneously from inert matter
Exmaple
Frongs that grow in mud and stagnant water
The first to refute this idea was
Francesco Redi
by making some experiments
Redi's experiment
Put two pieces of meat into two containers ( one opened the other covered by gauze)
When the times passed, both containers meat had decomposed
Maggots were only present in the opened one, they were fly larvaes
Louis Pasteur
also disproved spontaneous generation
He proved that living things come from another living thing
Pasteur's experiment
1
He put puored beef broth in two flasks, with a curved narrow neck. Then he boiled them and let them stand. He also broke the nek of one flask
2
Later, he saw that the broth of the unbroken nek hadn't decomposed. But the one the one of the broken neck had decomposed
Conclusion
He demostrated that the microorganisms were in the air, attached to dust particles.
Modern theories about the origin of life
Curiosity
The oldest evidence of life is in Greenland, a chemical 3.8 billion years old
Two theories
Panspermia
It says thet life was originated in space and was carried to Earth by meteorites
Carbon-based organic matters has been indentified in some comets and meteorites
Abiogenesis
Combines several theories
Development of complex molecules
Appearence of the first cell,
chemical evolution
Formation of simple organic molecules from inorganic molecules
Primordial soup
In 1920, Oparin and Haldane workind independently described a primitive oxygen-free atmosphere
Composed of gases like, hydrogen, methane...
Ultraviolet radiation and electrical energy acted as an energy source
This energy produced simple molecules thet are deposites in the water of the first seas
More complex structures formed later, with membranes and will produce the first cells
Many researchers belive that the early atmosphere contained carbon dioxide and nitrogen produced by volcano activity, but other scenarios are currently being examined.
Theory of hydrothermal vents
(life started in hydrothermal vents)
Vents are located on the seafloor along the ocean ridges
Are protected from solar radiation, wind and strong currents from the surface
Thise places are rich in methane, hydroge and iron, so life forms like bacteria that feed on these compounds poliferated there.
Thise bacterias resist high temperatures and are the oldest organisms known
