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(5 billion years ago) Formation of our Sun
Our solar system was a huge mass of gas and dust in space, until gravity pulled these pieces together to form the sun. This can be easily described as the beginning of time because the formation of the sun led free particles to collect to make planets and our solar system by its gravitational pull, over time. -
(4.6 billion years ago) Formation of our solar system
Our solar system was formed by the particles surrounding our sun in 400 million year time span. Debris was collected in space to form planets, which grew larger as more debris was collected. This is also when the very first pieces of debris collected and began the formation of our Earth. -
(4 billion years ago) The Earth
The small particles in space that created the planets of our solar system, also created our Earth by colliding under the force of gravity. Those particles were the beginning of everything for humans, animals, and so those small particles that once began the creation of our Earth, mean the world to us, literally. -
(4 billion years ago) Earth's Formation
Along with the formation of the Earth, was the formation of the primary elements. These elements were then assembled into orgainc compounds which are now the basis of all life! The creation of organic compounds was an extremely important part in the creation of our Earth, and us. Essentially, it has affected all life because humans, animals, and plants are all composed of organic compounds. -
(3.5 billion years ago) Stromatolites and fossils
The first stromatolites, colonies of cells that form layered structures, and fossils are dated back to 3.5 billion years ago. Many of the oldest known fossils are similar to cyanobacteria, which is a modern group of photosynthetic, unicellular, prokaryote. Scientists are able to infer that some life had become photosynthetic about 3 billion years ago because of traces of photosynthetic activity. -
(3 billion years ago) Photosynthetic Plants
Forms of life had become photosynthetic, using or formed by photosynthesis. This is very important because the plants could keep the amounts of oxygen and carbon dioxide in the atmosphere relatively level. This way plants can take in energy, as well as aerobic organisms. -
(2.2 billion years ago) Earth's advancements
The Earth began to take the form of what we are familiar with today. The Earth began to take the form of the planet that we call our home today. The Earth was not yet suitable for life, but it had made huge changes since it's initial creation. -
(2 billion years ago) Oxygen levels
By 2 billions years ago, the levels of oxygen in the atmosphere reached today's level of oxygen. This marked the beginning Earth and its acceptence of life. Without this, many organisms would have had to found a different source for energy. -
(1.5 billion years ago) Prokaryote
A small aerobic prokaryote was implanted and started to live and reproduce inside a larger prokaryote, also known as endosymbiosis. Many scientists belive these endosymbiotic aerobic prokaryotes changed over time to modern mitochondria. These mitochondria undergo aerobic respiration in eukaryotes which creates energy for most living things without the build up of lactic acid. -
(1 billion years ago) Ozone
1 billion years ago ozone was formed, which protected organisms from harmful UV rays, allowing them to live on land. Otherwise, the Ultraviloet rays could damage our DNA. Without ozone, there could be no life on land. -
(1729-1799) Lazzaro Spallanzani's experiment
Spallanzani, the Italian scientist, conducted an experiment to, as well as Redi, test the theory of sponatneous generation. He boiled two pots of broth, and then sealed one pot and let the other sit unsealed. After a few days he concluded that the unsealed broth became cloudy, but the broth in the sealed pot remained clear. Unfortunately, Spallanzani's experiment was rejected as well because of the disregard to the "vital force". -
(1822-1895) Louis Pasteur
In the mid-1800's Pasteur did an experiment to clear up the issue of spontaneous generation and biogenesis, while includling the theory of "vital force". Pasteur's experiment was similiar to Spallanzani's except that Pasteur used curved necks for his flasks. Because of the pots unique shapes, Pasteur did not have to cover the pots which allowed "vital force" to come in. His results were the same as Spallanzani's, and the controversey was cleared up. -
(1920's) Oparin and Haldane
Alexander I Oparin and John B. S. Haldane hypothesisiezied that the early atmoshpere contained water vapor, ammonia, and carbon compounds. They proposed that these gases may have formed organic compounds like amino acids at high temperatures. Then when the Earth cooled these simple organic compounds became more complex through a series of chemical reactions. -
(1626-1697) Franseco Redi's experiment
Franseco Redi did an experiment to test the belief of spontaneous generation, the thought that living organisms can arise from non-living objects. His expirement consisted of two jars with meat inside. Redi covered the lid of one, whereas he left the other open. He waited a few days and noticed that the covered lid didn't have any maggots on the meat but the uncovered meat had many maggots. However, Redi's theory of biogenesis was rejected because the "vital force" was cut off. -
(3 billion years ago)
Forms of life had become photosynthetic, using or formed by photosynthesis.
