Plate Tectonics, Solar System Origin, and Life’s Genesis
Plate Tectonics
Continental drift and seafloor spreading unite in a more complete theory known as plate tectonics. Under this theory, the rigid outer layer of the Earth is over a weaker region called the asthenosphere. The lithosphere is divided into several pieces called plates that are moving and continually changing in shape and size. The plates move and deform along their edges.
When the plates separate, mantle material rises, creating new ocean floor. When the plates collide, mountain ranges like the Himalayas form. Volcanic islands also appear.
The theory of plate tectonics is supported by the global distribution of volcanic hotspots and earthquakes, as both phenomena are closely associated with plate boundaries.
Origin of the Solar System
Our solar system is formed by the Sun, the known planets, their satellites, comets, and other celestial bodies that are subject to the Sun’s gravitational attraction.
The solar system’s orderly nature suggests that it formed from a huge cloud of dust and gases in rotation, called the solar nebula. This cloud began to collapse gravitationally, contracting into a rotating disk that heated up through the conversion of gravitational energy into heat energy.
The formation of the Sun marked the end of the shrinkage period. Subsequent cooling resulted in the condensation of matter into small rocky and metallic solids. Repeated collisions of particles gradually formed bodies the size of asteroids. Over millions of years, these bodies became the planets.
The planets are divided into two distinct groups by the asteroid belt: the inner planets and the outer planets.
A type of celestial body now recognized is the dwarf planet.
Miller’s Experiment on the Origin of Life
Miller built a device that circulated a mixture of methane, hydrogen, ammonia, and water, which was kept boiling and subjected to a series of electric shocks.
It was concluded that the primitive conditions of Earth were not very different from those simulated in the laboratory. Currently, it is believed that the existing atmosphere on the early planet was not exactly the one Miller used.
The Miller experiment was very important, generating a fertile intellectual framework not only for generating hypotheses but also for designing new experiments rigorously simulating conditions and processes to understand the origin of life.
Lamarck’s Theory
Lamarck proposed the first coherent theory of evolution, the transformation of living beings. He posited that life is a natural phenomenon that originates in spontaneous generation by the action of natural forces capable of generating the simplest living organisms.
The theory of spontaneous generation persisted due to observations such as the thriving colonies of organisms found on decomposing meat or vegetables, which appeared to arise spontaneously.