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(5 BYA) The Sun is Formed
Dust and gases in space from stars that had exploded gathered to form the sun. The pull of the sun caused the remaining dust and particles to swirl araound it. This is what started our solar system. -
(4.6 BYA) Earth begins to form
The Earth started to form from the dust and debri around the sun, crashing and sticking to more matter as its gravity grew. -
(4BYA) Earth is formed
The Earth was molded into its sphereical shape that it is today and formed its magnetic field. The magnetic field protects the earth from the solar wind. -
(4BYA) First signs of life
Forms of life were introduced to the Earth. These life forms were similar to the aechaebacteria today, living in harsh conditions. -
(3.5 BYA) Stromatalites are created
Types of cyanobacteria caused the formations of these kinds of rocks. They are made of layers that built up over time. The layers were formed by particles in the air caught to the bacteria living on it. -
(3BYA) Photosynthetic life
Some cells were had developed to become photosynthetic -
(2.2 BYA) Current Apperarance of the Earth
The Earth looked like what it its today. It had the atmosphere, bodies of water, and land masses like it daoes today. -
(2 BYA) Oxygen levels meet today's
The amount of ozygen on the Earth at this time are the same as they are today. Oxygen was being produced by aerobic life. -
(2-1.5 BYA) Eukaryotes
Eukaryotes had started to develop on Earth. The theory about their formation is that they formed by the process of symbyosis, by which an aerobic prokaryote was engulfed by a larger anaroebic cell. -
(1 BYA) Ozone
The ozone is O3, when O2 is bonds with Os that had been separated by the sun from O2. It protected life forms from ultraviolet radiation, though it could be deadly to life if they came in contact with it. -
(1665) First Microscopes
Hooke and other scientists used the microscope to study cells and find many tiny unknown creatures. The tiny microorganisms in the air led the scientists to believe in spontaneous generation. -
(1700s) Spallanzani's experiment
Lazzaro Spallanzani was an Italian scientist that, like Redi, designed an experiment to test spontaneous generation. He placed meat broth in flasks that were opened or sealed. The meat broth in the sealed flask remained clear while the broth in the open flask turned cloudy. -
(1800s) Pasteur's experiment
He used a flask with a curved neck but still open. Boiled broth in the flask remained clear, but when it was taken off, it turned cloudy. It disproved spontaneous generation. -
(1600s) Redi's experiment
Redi found during his experiment that maggots were formed only when flies touched the meat. It questioned spontaneous generation. -
(1800s) Radiometric dating
A method of using isotopes of an element to find the age of an object. Some isotopes are radioactive, and, over, they break down to have thei amoun in their halflives. By finding the amount of the radioactive isotope and using the halflife, the age of an object can be found. -
(1953) Urey and Miller
Urey and Miller's experiment tested Oparin's hypothesis. They simulated the condition of the atmosphere. They simulated the lightning that was present with electric sparks. Their experiment showed that amino acids, ATP, and nucleotides could have formed at that time. -
(1800s) Oparin's Hypothesis
Oparin came up with his hypothesis that the atmosphere had ammonia, hydrogen gas, water vapor, and hyfrogen and carbon compounds, and that high levels of energy and radiation would cause the formation of organic compounds. -
(1938) Lynn Margulis
Margulis formed the theory that eukaryotic cells formed by the process of sndosymbiosis. An aerobic, prokaryotic cell was engulfed by a larger, anaerobic, prokaryotic cell. -
(1980s) Thomas Cech
Cech found that a certain RNA molecule that he called a ribozome could act as a catalyst. Many studies were done based off of his discovery. -
(1900s) Sidney Fox
Fox was a scientist that did research on the physical structures that could have formed the first cells. He used microspheres and coacervates that could have become organized to form cells.
