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(5BYA) The Formation of the Sun
The sun is formed after a swirling mass of gas and dust are pulled together. Afterwards, the leftover debris collides over time forming the plants giving us the solar system we have today. -
(4.6BYA) The Earth Forms
Debris from the formation of the sun collected and began to form Earth without its crust. -
(4BYA) The Earth's Crust is Formed and the First Cells are Created
- The Earth's surface cooled and hardened creating its crust. This is the time at which Earth is considered to be formed.
- The first cells are created which are thought to be anaerobic, heterotrophic prokaryotes.
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(3.5BYA) Stromalites are Created
Stromalites are created from layers of Lynbgya cells stacked on top of eachother. Stromalites are some of the oldest fossils found and are related to modern cyanobacteria. -
(3BYA) Photosynthesis Begins
At this time, some forms of life became photosynthetic meaning they used the process of photosynthesis to make energy. One of photosynthesis's bi-products, oxygen, lead to the emergence of species who use anerobic respiration. -
(2.2BYA) Earth Appears as It Does Today
As the Earth cooled, it began to appear as it does today complete with land forms and oceans. -
(2BYA) O2 Levels Reach Today's Levels
Overtime, photosynthetic organisms released enough oxygen that the O2 levels inside of the Earth's atmosphere were the same as they are today. -
(2.0-1.5BYA) Relationship Between Anaerobic and Aerobic Prokayotic Cells is Formed
Large anaerobic and small aerobic prokaryotic ells began a mutually beneficial relationship which provided them with a type of energy synthesis. Overtime, the aerobic prokaryotic cells became modern mitochondrions. -
(1BYA) The Ozone Layer is Formed
O2 was split by the sun's rays leading to the creation of O3 in the upper atmosphere. This new O3 formed the ozone layer which protects life on Earth to this day from UV radiation. -
Everything From 1600s to Date Part 4
In 1938, Lynn Margulis proposed the theory known as endosymbiosis, which was from between 2.0 to 1.5 million years ago, a aerobic cell was engulfed by an anaerobic cell, and continued living in it, being believed to be the mitochondria of today's eukaryotic cells. In 1953, Urey and Miller performed experiments that made a variety of organic molecules, such as amino acids, using Oparin's hypothesis as a starting point. -
EVerything from 1600s to Date Part 1
Radiometric dating has allowed scientists to determine that the earth's age by using a dating method that involved uranium and thorium in rock crystals. In 1665, Robert Hooke invented the first light microscope, and was used to discover tiny microorganisms had simple structures, were vastly numerous, and that they were virtually everywhere. It was also believed that they were spontaneously generated from a “vital force”. -
Everything From 1600s to Date Part 2
In the middle of the 17th century, the Italian scientist, Francesco Redi, performed experiments dealing with fruit flies ad maggots, that proved spontaneous generation was false. In the 1700s, Lazzaro Spallanzani formed a hypothesis that microorganisms did not spontaneously generate, but actually came from other microorganisms. He then experimented on this hypothesis that involved flasks filled with broth that was heated and microorganisms in the air. -
Everything From 1600s to Date Part 3
In the mid 1800s, Louis Pasteur performed an experiment that was a variation of Spallanzani's except he used a curved flask. His experiment concluded with Spallanzani's hypothesis as true, ending the spontaneous generation idea. In the 1920s, Oparin formed a hypothesis that stated when certain gases could form simple organic compounds at high temperatures, and then when bodies of water started forming, these compounds would form macromolecules essential to life. Paved way for future exp. -
Everything From 1600s to Date Part 5
Sidney Fox and other scientists, experimented/researched on the structure that could have belonged to the first cells, which involved making them in the laboratory from simple organic chemicals. In the 1980s Thomas Cech found a RNA in some eukaryotes can act as a catalyst in the replication of itself, and this helped to support the theory that life could have began from self-replicating RNA molecules.
