7;Breitenbach,Kuntz;History of Earth Timeline By 2013breiteca Jan 1, 2011 (5 BYA)- And There Was Light During this time the solar system was a swirling mass of gas and dust. Over time, most material was pulled together by gravity and formed the sun. Jan 29, 2011 (4.6 BYA)- The Thing We All Have In Common The Earth was formed during this time through collisions of space debris. Mar 14, 2011 (4 BYA)- Crystals Fall From A Bright Star On the Earth, rocks and crystals were beginning to form. Organic molecules also began to accumulate. Mar 14, 2011 (4 BYA)- Cell Life is Just the Beginning Archaea are thought to be similar to the types of cellular life that first populated Earth. Apr 20, 2011 (3.5 BYA)- A Journey of a Thousand Years Begins With A Single Rock Lynbgya cells often grow in colonies and form layered structures called stromatolites began to form and develop. Life is beginning. May 26, 2011 (3 BYA)- Take A Picture Some forms of life began to become photosynthetic. Jul 24, 2011 (2.2 BYA)- Earth Now and Then Earth for the most part looks the same way it does now. Aug 7, 2011 (2 BYA)- Breathe Deep Oxygen levels reach today's levels. Sep 12, 2011 (1.5 BYA)- Reproduction Begins Around this time aerobic prokaryote's were beginning to reproduct. Oct 9, 2011 (1 BYA)- Living On Land Ozone forms, which protects organisms from harmful UV rays so they can exist on land. Dec 31, 2011 (1600's)- Microscopes The first microscope is used to discover that microorganisms are simple in structure and amazingly numerous and widespread. Dec 31, 2011 (1600's)- Redi's Expierments He noticed and describe the different developemental forms of flies. Dec 31, 2011 (1700's)- Spallanzani's Expierements He designed an expierement to test the hypothesis of spontaneous genereation of microorganisms, Dec 31, 2011 (Mid 1800's)- Pasteur's Expierement He made a curved necked flask that allowed the air inside the flask to mix with air outside the flask. The curve in the neck of the flask prevented solid particles from entering the body of the flask. Dec 31, 2011 (1938)- Lynn Margulis She proposed that early prokaryotic cells may have developed a mutually bennifical realtionship. Dec 31, 2011 (Mid 1900's)- Fox He did extensive research on the physical structures that may have given rise to the first cells. Dec 31, 2011 (1949)- Radiometric Dating It is a technique that establishs the age of a material. Scientists can now look at ages of rocks to establish years that thet happened. Dec 31, 2011 (1952)- Oparin's Hypothesis He hypothesised at high temperatures gases might have formed simple organic compunds such as amino acids. It would ultimatly have resulted in the macromolecules essential to life such as proteins. Dec 31, 2011 (1953)- Urey and Miller's Expierement The tested the hypothesis of Oparin. Their expierement produced a variety of organic compounds including amino acids. Dec 31, 2011 (1980)- Thomas Cech He found that a type of RNA found in unicullular eukaryotes is able to act as a chemical catalyst. He used the term Ribozyme for an RNA molecule.