It was a swirling mass of gas and dust. Overtime materials were puleld together by gravity and formed the sun a few million years later.
pd 7 miller lee history of earth timeline
(4.6 BYA) Earth Formation
Earth grew larger sd gravity pulled in more debris, it released great amounts of thermal energy. Some collisions would have released enough energy to melt large portions of earths surface.
(4 BYA) Oldest known rocks and crystals
50 Million human lives spands is equal to the earths life spand. Scientists infer that organic molecules began to accumilate about 4 billion years ago.
(4 BYA) Organic molecules
Organic molecules began to accumulate about 4 billion years ago. This was infered after the discovery of the oldest rocks and crystals.
(3.5 BYA) Fossils
Lynbgya cells often grow in colonies and form layerd structures called stromatolites. Fossils of stromatolites as old as 3.5 billion years are known,
(3 BYA) Photosynthetic Life forms
Some forms of life become photosynthetic by 3 billion years ago. Scientists infer this from a varity of geoligic events such as chemical traces.
(2.2 BYA) Earth Completion
Aroung 2.2 billion years ago, earth probably appeared as much as it does today.
(2 BYA) O2 levels
The O2 levels have reached the same level as they are today.
(Between 2 BYA- 1.5 BYA) Aerobic prokaryote
A small type of aerobic prokaryote was engulfed by and began to live and reproduce inside of a larger, anaerobic prokaryote, this therory is called endosymbiosis.
(1 BYA) Ozone
Ozone formed which is also called O3, to protect organisms from harnful UV rays so they could exist on land.
(1947) Thomas Cech
He grew up in Iowa City. He obained his Ph.D. in chemistry and then went to become a proffesor in chemisty and biochemistry.
(1952)Miller and Urey Experiment
This experiment simulated hypothetical conditions thought at the time to be present on the early earth. It also tested the occurence of origins of life.
(1912) Sidney Fox
Reasearched on physical structures that may have given rise to the first cells.
A technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.
(1938) Lynn Margulis
an American biologist and University Professor in the Department of Geosciences at the University of Massachusetts Amherst. Most recognize her for her theory on the origin of eukaryotic organelles.
(1600) The first microscope
English scientist Robert Hooke studied the nature by using an early ligt microscope.
(1729) Spallanzani's experiment
Designed an experiment to test the hypothessis of spontaneous generation of mircoorgansims. He alos hypothesized that microorganisms formed not from ait but from other microorganisms.
Redi noticed and described the different development form of flies. He observed that maggots seemed to appear where adult flies had landed. His hypothisis was that meat kept away from adult flies would remain maggot free. Redi's ezperiment showed that flies come only from eggs laid by other flies.
(1822-1895) Pastures experiment
Pasture set up experiments to answer objections to spallazani's experiment. He made a curved - neck flask that allowed the air inside the flask to mix from air outside the flask. The broth was boiled inside the flask.
(1924) Oparin's hypothesis
Oparin hypothesized that the formation of amino acids and proteins from non-living chemicals, this process is known as abiogenesis,