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(5 Billion Years Ago) Solar System Forms
Today, we have evidence that as a swirling ball of gas and dust, the solar system began to form. A few million years later, the Sun began to form by the gravity pulling this material together. The remaining material: gas dust and debris, swirled around the sun which lead to the formation of planets. -
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(4.6 Billion Years Ago) Earth Began To Form
The earth began to form just as other planets, and continued to grow from gravity pulling space debris, and forcing them to collide. This would lead to thermal energy. The earth's surface allows us to find the age of it. -
(4 Billion Years Ago) Atmosphere
Volcanoes emit massive amounts of gas, forming an atmosphere, -
(4 Billion Years Ago) Organic Molecules
The oldest known rocks and crystals are 4 billion years old.. Collisions from space debris on the Earth's surface stopped and organic molecules began to form. -
(3.5 Billion Years Ago) Life
Cyanobacteria, photosyntheric unicellular prokaryotes, would layer to form stromalites. Fossils 3.5 BYA of this were found. -
(3 Billion Years Ago) Photosynthesis
Forms of life became photosynthetic. This is inferred by geologic evidence from chemical traces of photosynthetic activity. now we know that oxygen began to be released, would damage the unicellular organisms -
(2.2 Billion Years Ago) Fully Formed
By this time, Earth would've looked the same as it does today! -
(2 Billion Years Ago) Oxide
Oxide levels reach today's levels. -
(2-1.5 Billion Years Ago) Endosymbiosis
A great amount of evidence displays the evidence to the theory of endosymbolosis. A small aerobic prokaryote was "swallowed up" by and reproduced inside a larger anaerobic prokaryote. This is beneficial towards the environment by providing a method of energy synthesis. Scientists infer this is how mitochondria evolved, which perform anaerobic respiration in eukaryotic cells. -
(1 BYA) Ozone (O3)
The ozone formed, protecting organisms from harmful UV rays so they could exist on land. -
(1665) First Microscopes
Robert Hooke and many other scientists used microscopes to discover microorganisms. -
(1668) Redi's Experiment
Redi takes a step forward in disproving spontaneous creation of living things. He covered one jar of meat and not the other. He found only fly maggots on the not covered jar because flys would actually come in contact with the meat. -
(1700's) Spallanzani's Experiment
Spallanzi hypothesized that microorganisms formed not from air, but from other microorganisms. He boiled two flasks and sealed one after. The one that was sealed remained clear and the other became cloudy. He concluded that it became cloudy from microorganisms the air. Opponents still opposed this idea therefore it was kept alive for another century. -
(mid-1800s) Pasteur's Experiment
To end objections to Spallanzi's hypothesis Pasteur conducted a better experiment. He made flasks that allowed air inside the flask to mix with air outside the flask. It did not allowed solid particles in. The flasks remained clear for a year. When he broke off the neck that prevented solid particles from getting in, they became cloudy and contaminated with microorganisms within a day. This ended the belief of spontaneous generation. -
(1900s) Fox
Sidney Fox and many other scientist did extensive research on physical structures that could've given rise to the first cells. These structures are microspheres and coacervates. -
(1920s) Oparin's Hypothesis
Oparin hypothesized that early atmosphere had ammonia, hydrogen gas, water vapor, and compounds made of hydrogen and carbon. He said that at high temperatues, these gases could form organic compounds. -
(1900s) Lynn Marulis
Proposed that early prokaryotic cells may have developed a mutually beneficial relationship. -
(1949) Radiometric Dating
The method of establishing the age of materials was created. It is in important in finding out how and when the Earth formed -
(1953) Urey and Miller
Concluded that organic compounds might only have been possible in areas protected from the atmosphere, such as undersea hot springs. -
(1980s) Thomas Cech
Thomas Cech discovered ribozymes. RNAs molecule that can act as a catalyst and promote a specific chemical reaction. His findings support the hypothesis that life could have started with self-replicating molecules of RNA
