-
(5 BYA) Formation of the Solar Sysytem
Our solar sysytem was a swirling mass of gas and dust and overtime most of this material was pulled together by gravity and it formed the sun. The remaining debris, gas, and dust circled the sun. This resulted in the formation of the planets and the sun. -
(4.6 BYA) Earth Formation
Earth began to form and grow by colliding with space debris. It also released a great deal of thermal energy and some collisions would've released enough energy to melt large portions of this surface. -
(4 BYA) Age of Earth
Estimates of earths age was made by studying layers of sedementary rock in earths crust. The estimated age of earth is about 700,000 times as long as the period of recorded history. -
(4 BYA) Archaea Bacteria
Methanosarcina barkeri is an archael species that produces methane during Metabolisim. They are similar to cellular life. -
(3 BYA) Photosynthesis
Some forms of life became photosynthetic. -
(2-1.5 BYA) Eukaryotic Cells Evolved
A type of small aerobic prokaryote was engulfed by and began to live and reproduce inside of a larger anaerobic prokaryote. (Endosymbosis). -
(3.5 BYA) Cyanobacteria
Fossils of Stromatolites were found. These fossils show that prokaryotic life still remains on Earth today. -
(2.2BYA) Gas on Earth
Earth probably appeared as it did today. Volcanoes emitted gas forming an atmosphere. Oxygen is a byproduct that damaged the unicellular organisims. -
(2 BYA) O2 Levels
O2 levels reached todays levels. -
(1 BYA) Ozone Formation
Ozone (O3) formed- protected organisims from harmful UV rays so they could exist on land. Suns wavelengths split O2 particles and the resulting single O particles collided with other 02 particles creating the 03 (O Zone). -
(1600's) Redi's Experiment
During Redi's expirament, Maggots were found only in the control jars (left open) because that was the only place where adult flies could reach the meat to lay the eggs. -
(1953) Urey and Miller
The Miller-Urey experiment was intended to test Oparin's hypthesis about the conditions for the formation of organic molecules on early earth. This experiment is considered to be a milestone in scientific investigation. -
(1900's) Sidney Fox
He did extensive research on physical structures that may have given rise to the first cells (microspheres and coacervates). -
(1900's) Lynn Margulis
He proposed that early prokaryotic cells may have developed a mutually beneficial relationship. -
(1980's) Thomas Cech
He found that a type of RNA found in some unicellular eukaryotes is able to act as a chemical catalyst (ribozyme). -
(1800's) Radiometeric Dating
A method used to establish ages of materials on Earth. -
(1800's) Oparins Hypothesis
His hypthesis was that since the atmosphere contained ammonia, hydrogen gas, water vapor, and compounds made of hydrogen and carbon. At high temperatures theses gases might have formed simple organic compounds such as amino acids. -
(1665) First Microscopes
Robert Hooke used an early microscope to see cells in thin slices of cork and what he saw indicated thqt he had clearly had observed the remains of cork cells. -
(1700's) Spallanzani's Experiment
He boiled meat broth in open flasks. Then, he sealed the flasks of the expiramental group by melting the glass neck of the falsk closed. The broth inside remained incontaminated by microorganisims. -
(1700's) First Microscope
Scientists began using the microscope and discovered that the world is filled with tiny little creatures. They discovered that there are many micoorganisims in the world even though they are very small.This led them to believe that microorganisims come spontaneously in the air. -
(1800's)Pasteur's Experiment
A flask with a curved but open neck prevented microorganisims from enetering. Broth boiled in the flasks became contaminated by microorganisims only when the curved necks were removed from the flasks.
