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(5 BYA) Formation of Solar System
The solar sytem was formed by a swirling mass of gas and dust. Over time material was pulled together by gravity, and left over debris circled the sun and formed planets. -
(4.6 BYA) Earth's Formation
The earth began to form from colliding debris. -
(4 BYA) The Atmosphere
The atmosphere was created from gas emitted by volcanoes. -
(4 BYA) Archaea Bacteria Formed
Archaea obteined energy through chemosynthesis. Chemosynthesis is when CO2 serves as a carbon source for the assembly of organic molecules and energy is obtanied from oxidation of inorganic substances. -
(3.5 BYA) Stromatolites
Stromatolites existed and were formed. A stromatolite is a layered structure of cells. -
(3 BYA) Photosynthesis
Some life forms began to become photosynthetic. Being photosynthetic means absorbing energy for the sun, CO2, and water to produce carbohydrates and oxygen. The production of oxygen, however, was very damaging to many early unicellular organisms. -
(2.2 BYA) The Earth As It Appears Today
The Earth began to appear more like it is today. The cause of this was gravity because gravity pulled more and more pieces of debris toward it which addded to its overall size. It also became more round similar to how it is today because gravity made all its debris and particles condense. -
(2 BYA) The Ozone
The ozone layer was formed, which created protection for plants and animals from ultra violet rays. Also, during this time oxygen levevls reached their maximum amount, similar to the levels of oxygen today. -
(Between 2 and 1.5 BYA) The First Eukaryote
The first eukaryotes were created. The first eukaryotes were created when a type of small aerobic prokaryote was engulfed by a larger anaerobic prokaryote, and when the smaller prokaryote was engulfed it began to live and reproduce inside the larger prokaryote. This theory is called endosymbiosis. -
(1 BYA) Organic Molecules, RNA and Respiration
Organic molecules including: amino acids, carbohydrates, mitrogenous bases, and hydrocarbons, were formed. Cells became molecular systems with membranes. RNA started controlling and regulating heredity. Also, cellular respiration, which is the process of obtaining energy from carbohydrates and oxygen combines with glucose to produce water and carbon dioxide, developed. -
(1600-1700) Redi's Experiment
Redi provided an alternate view to the idea of spontaneous regeneration. His experiment consisted of taking meat placing them in jars leaving one open to flies and one closed. Maggots grew on the meat in the open jar. Redi concluded that meat should be closed off when not being eaten. -
1600-1700) Hooke used light microscope
Hooke used the light microscope to study cork and discover cells. -
(1700-1800) Spallanzani’s Experiment
Spallanzani’s experiment showed that if broth was covered it wouldn’t be cloudy and filled with microorganisms
It showed that broth and food should be covered after it was heated. People opposed his findings, saying the broth was heated too long therfore killing the "vital force". -
(1800-1900) Pasteur's Experiment
Pasteur used open curve-necked to prevent solid particles, microorganisms, from getting into the body of the flask. The flasks were filled with broth and heated. The flasks remained clear during the experiment, excpet when he broke the curved-neck off the flask, then the flasks became contamineted with microorgansims that came from the air. The experiment disproved spontaneous generation and a new theory, biogenesis, was used to explain that living things came from other living things. -
(1900-The Present) Oparin
Oparin hypothesized that the early atmosphere contained ammoonia, hydrogen gas, water vapor, and compounds made of hydrogen and carbon, such as methane. He said, at high temperatures, these gases could have formed simple organic compounds. He also said that water vapor condensed and formed bodies of water, and that organic compounds collected in the water. Over time these compounds entered chemical reactions to result in macromolecules. -
(1900-The Present) Harold C. Urey and Stanley L. Miller's Experiment
Miller and Urey created an experiment to test Oparin's hypothesis. Their experiment used an appratus filled with gases Oparin hypothesixed were present during early Earth. As the gases circulated the chamber, electric sparks were provided to drive chemical reacctions. This experiment produced a variety of organic compounds, proving Oparin's hypothesis to be true. -
(1900-The Present) Sidney Fox
Fox researched and studied the physical structures that possibly gave rise to the first cells. These structures, microspheres, which are made of one type of molecule, and coacervates, which are composed of different types of molecules, form spontaneously under certain conditions, but do not have all the properties of life. -
(1900-The Present) Thomas Cech
Cech discovered that a type of RNA thats found in some unicellular eukaryotes is able to act as a chemical catalyst. He called this RNA a ribozyme. -
Radiometric Dating (1900-The Present)
Radiometric dating is used to establish the age of materials. This process is used by looking at the decay and half life of isotopes. -
Lynn Margulis (1900-The Present)
Lynn Margulis said that early prokaryotic cells may have developed mutually beneficial relationships. This relationship meant that a small type of aerobic prokaryote was engulfed by a large anaerobic prokaryote and while the small prokaryote was inside the larger one it lived and reproduced. This would then create eukaryote cells.
