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(5 Billion Year Ago) The Solar System
5 billion years ago, the solar system. However, the sun did not form until a couple million years later. -
(4.6 Billion Years Ago) The Formation of The Earth
The Earth begins to form. It grows in size by colliding and combining with space debris, which were attracted to the Earth's gravitational pull because of its size conpared to the space debris. -
(4 Billion Years Ago) Formation of Earth's Atmosphere
Volcanoes form on the Earth and erupted, spewing gas. These gases formed the Earth's atmosphere. -
(3.5 Billion Years Ago) Prokaryotes
Fossils that are from this time are thought to be cells that are similar in both size and shape to modern prokaryotes. The first cells were also probably developed in an environment with organic molecules for food. This shows that around this time period was when the first organic and functional prokaryotes that were similar to modern prokaryotes were formed. -
(3 Billion Years Ago) Photosynthetic Life Forms
Some life forms became photosynthetic. These life forms were able to convert carbon dioxide into organic compounds using the energy from the sun. The oldest fossils of cells are similar to modern cyanobacteria, which are a group of photosynthetic prokaryotes. -
24 July 2011,( 2.2 Billion Years Ago)
The Earth has developed and appears to be very similar to how it is today. -
7 August 2011, (2 Billion Years Ago)
Oxygen levels on Earth match oxygen levels today. -
9 October 2011, (1 Billion Years Ago)
Ozone (O3) formed – protected organisms from harmful UV rays so they could exist on land -
(1650) Francesco Redi
He conducted an experiment to prove that flies do not spontaneously generate from rotting meat, but are born of adult flies that have landed on the meat and layed their eggs there. He unproved the previous conception that living things could spontaneously generation from non-living things. -
(1665) Robert Hooke
Hooke used light microscope to study plant cells. He looked at a piece of cork underneath a mircoscope and discovered that they were made up on smaller parts. This proved that there were things that were composed of smaller pieces than were previously thought. This was also the first time that anyone had ever seen cells underneath a mircoscope and recongized them as such, -
(1673) Anton van Leeuwenhoek
He was the first to discover microorganisms in water using microscope. The mircroscope he used was different than Hooke's. The was magnification 10x more powerful. -
(1850) Louis Pasteur
He put broth in a curve necked flask. This did not prevent solid particles from entering the neck of the flask (such as microorganisms), but it did prevent them from entering the flask. itself which contained the broth. The broth only became cloudy when the necks were broken off and microorganisms could reach the broth. This proved once in for all, and without a question, that spontenous generation was false. -
(1950s) Sidney Fox
Fox did extensive research on the physical structures of the first cells. It was discovered that microspheres(composed of many protein molecules) and coacervates(droplets composed of lipids, sugars and amino acids) can form spontaneously under certain conditions. -
(1953) Stanley Miller and Harold Urey
These two scientist set up an experiment to test Oparin’s hypothesis. The test included an apparatus containing the gases that Oparin thought were present in early Earth and electric sparks to simulate the lightning, which was the source of energy for chemical reactions. The experiment yielded organic compounds. -
(1960) Lynn Margulis
He hypothesized that organelles were originally separate organisms living in cells through endosymbiosis(when one organism lives inside another). He thought that endosymbiosis were how eukaryotic cells evolved. -
(1980s) Thomas Cech
Thomas Cech discovered that a type of RNA in unicellular eukaryotes can like a chemical catalyst, similar to the way an enzyme acts. RNA enzymes are known as ribozymes, and have been a useful tool in gene technology. -
(1763) Lazzaro Spallanzani
He found that microorganisms infect broth if it is not sealed, but if the broth is sealed, the microorganisms cannot reach it. This proved that organic compounds did not generate randomly, but were from the air, and that was how they made the broth cloudy. The microorganisms were only able to get into the broth that was not sealed, because it was exposed to the open air. -
Radiometric Dating
Radiometric Dating is a method used to place the age of materials. Scientists use radio active materials that decay in half lives found in materials to estimate the age of the material. It has greatly affected how scientist are able to figure out how old the material is. -
(1920) Alexander Oparin
Alexander Oparin wanted to know how all the elements found originally on Earth were able to assemble to form organic compounds. He developed a hypothesis with John Haldane, stating that at high temperatures, the elements might have formed simple organic compounds, such as amino acids. Once the Earth cooled the simple organic compounds collected in water and had many complex chemical reactions. The source of energy from these reactions were from ultraviolet radiation and lightning.
