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(5 billion years ago) Mass of Dust
The universe was a swirling mass of dust. Over time some of this dust came together and formed the sun while the remaining dust circled around it. It’s believed the dust formed the planets through repeated collisions. -
(4.6 Billion Years Ago)
Earth grew larger and collisions between Earth and space debris created thermal energy. -
(4 Billion Years Ago) Age and Life on Earth
The age of the Earth is about 4 billion years old and that’s 700,000 times as long as the period of recorded history. Scientists have study the Earth’s layers to try to get a good estimate on the exact age of the earth, but never could. Regarding actual life on Earth, Archaea are thought to be similar to the types of cellular life that first populated the earth this many years ago -
(3.5 Million Years Ago) Fossils
Some fossils of stromatolites can be found that date back 3.5 million years ago! -
(3 Billion Years Ago) Photosynthesis
Some organisms became photosynthetic about 3 million years ago. -
(2.2 Billion Years Ago)
Earth's atmosphere lacked oxygen around this time. However, a rapid rise in oxygen favored cells on the Earth. -
(2 Billion Years Ago) We Can Breathe!
The O2 levels in the atmosphere reached today’s levels of O2. -
(1.5 Billion Years Ago)
A small type of aerobic prokaryote was engulfed and began to live and reproduce inside of a larger, anaerobic prokaryote. This created the theory endosymbiosis. -
(1 Billion Years Ago)
Ozone (O3) was formed. This protected organism from harmful UV rays so they could exist on land. -
(1600's) NEw discoveries
Hooke created the early light microscope, a device used to magnify an object by bending light rays. In addition to this discovery, Redi believed that if meat was kept away from adult flies, maggots wouldn’t appear on the meat. This experiment was questioning whether rotten meat generates flies and maggots -
(1700's)
Spallazani designed an experiment to test the generation of microorganisms. He believed they formed from other microorganisms and not just the air. -
(1800's) The Curved-Neck Flask
Oparin and Haldane hypothesized that the earth contained ammonia. To add to that, when Pastuer boiled the broth the same way Spallazini did, except in a curved neck flask, the broth stayed clear up for a year. However, once he broke off the curved neck, the broth became cloudy. Pasteur concluded that it became cloudy because of the microorganisms in the air. -
(1900's- Present)
Thomas Cech found that RNA in some unicellular eukaryotes can act as a chemical catalyst. Lynn Margulis found early prokaryotic cells may have developed a mutually beneficial relationship. Sydney Fox did research on physical structures that may have given rise to the first cells. Miller and Urey created an experiment that produced amino acids. Finally, A mixture of organic compounds were found in a fallen meteorite
