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(5 BYA) Formation of the Solar System
-The solar system was formed by gases and other swirling particles. Also, gravity pulled together the gases and dust to form the sun. Planets in the solar system were formed by collisions of the debris. -
(4.6 BYA) Formation of Earth
Earth first began to form by debris colliding. Then the surface of the Earth melted away many times. -
(4 BYA) Beginning of cellular life
-Because of the collisions of Earth and space debris began to stop, organic molecules began to accumulate, and the Earth began its cooling process. Also, the first types of cellular life began to populate the Earth at this time. -
(3.5 BYA) Stromalites
-Stromalites began to live at this time -
(3 BYA) Photosynthetic
Some forms of life have become photosynthetic. -
(2.2 BYA) Appearance of Earth
-Earth began to appear close to what it does today. -
(2 BYA) O2 Levels
-O2 levels reached today's levels -
(1.5 BYA) Endosymbiosis began
Endosymbosis started to form. Endosymbosis is when a type of small aerobic prokaryote is engulfed by and began to live and reproduce inside of a larger, anaerobic prokaryote. -
(1 BYA) Ozone layers formed
Ozone (O3) formed and protected organisms from harmful UV rays so they could exist on land. -
First Microscopes (1665)
Robert Hooke created the first light microscope by using optical lenses and it bends light rays to magnify the object. -
Redi's Experiment (1668)
Redi proved that biogenesis ocurred and not spontaneous generation. To prove this, he had a piece of meat kept away from flies and a piece of meat that had been exposed to flies. The one exposed to flies had maggots growing on it, but the one not exposed to flies, had no maggots. -
Pasteur's Experiment (1822)
Pasteur used a variation of Spallanzi's design to support that microorganisms are carried in the air, and do not arise by spontaneous generation. He did this by boiling broth and curving the neck of a flask. After a year, the broth remained clear. -
Radiometric Dating (1800s)
Radiometric dating is a technique used determine the age by comparing the relative %'s of a radioactive isotope and a stable isotope. -
(1938-present) Lynn Margulis
Lynn Margulis produced the endosymbiotic theory. This theory pretty much stated that early prokaryotic cells helped each other develop and reproduce. -
Spallanzi's Experiment (1700s)
Spallanzi discovered that microorganisms do not arise spontaneously, they are carried in the air. To prove this, he poured boiled broth into both an open flask and a sealed flask. Eventually, the open flask turned cloudy, and the sealed flask remained clear. -
(1894-1980) Oparin's Hypothesis
Alexander Oparin came up with an important hypothesis to solve the question: How and where did elements that existed on Earth and the rest of the solar system assemble to form into organic compounds. He hypothisized that at high temperatures, these gases (NH3, H2, H2O, and compounds of C and H2) might have formed simple organic compounds, such as amino acids. -
(1953) Urey and Miller's Experiment
Two students, Stanley Miller and Harold Urey, set up an experiment testing Oparin's hypothesis. They used a chamber that contained the gases that were in Earth's young atmosphere, and used sparks to supply energy to jumpstart chemical reactions. This experiment and many others produced a variety of organic molecules. -
(1912-1998) Sidney Fox
Sidney Fox researched th physical structures that may have given rise to the first cells. These cell-like structures include microspheres and coacervates. -
(1960) Thomas Cech
Thomas Cech found that a type of RNA found in some unicellular eukaryotes is able to act as a chemical catalyst, similar to an enzyme. He called these types of RNA: ribosomes.
