-
45,680 BCE
Creating the Earth and Moon
Earth formed in the primordial solar disk about 4.568 billion years ago and for hundreds of billions of years, being unprotected by an atmosphere, collided with other debris remaining from the solar disk. 4.4 billion years ago, one of these collisions was so large that the rubble that was thrown up from the impact began to orbit the Earth. We now have a fond connection with this rubble and even gave it a name: Moon. -
37,000 BCE
First Signs of Life?
Since volcanic carbon is heavier than organismic carbon, scientists believed that rocks should record this shift. In 2004, Researchers from the University of Copenhagen believe to have found this shift when they found this shift in 3.7 billion year old carbon rocks from Greenland. However, this conclusion has been met with skepticism. -
35,000 BCE
Emergence of Archaea!
3.5 billion year old rocks found in Australia have successfully been extracted for methane and shown to have low fraction of carbon-13, indicating that it was produced biologically. The only group of organisms alive today that release methane are a lineage of archaea called Euryarchaeota -
25,000 BCE
Emergence of Cyanobacteria and Oxygen!
4-2.5 billion years ago, the first living creature appears on Earth: Cyanobacteria. Evidence of this form of life has been found in Stromatolites. Also around this time, the first signs of atmospheric oxygen appear in the fossil record which is consistent with the presence of Cyanobacteria as it produces oxygen as a product of its photosynthesis. At this time, life was only present in Earths oceans and were limited to single-celled organisms. -
21,000 BCE
Multicellular Game Changers!
The emergence of multicellular organisms was a complete game changing event in the history of life on Earth. The first evidence of a multicellular organism dates back to 2.1 billion years ago! The fossil is of a scalloped disk and measures about 12 centimeters across. Why were these organisms the game changers? Because they are the start of a huge boom in the diversity of life. -
18,000 BCE
The Debute of Eukarya!
Eukarya are much newer life compared to Cyanobacteria and Archaea, making their debute 1.8 billion years ago. The first of the eukarya were rather small, measuring only 100 micrometers across. -
15,000 BCE
Desolate or not?
1.5 billion years ago, although Earth appeared to be a desolate place, it in fact was teaming with life dominated by microbes in the oceans. -
6500 BCE
Its an Animal Baby! No Really.. It is.
As surprising as it may be, the first appearance of animals in the fossil record dates about 650 million years ago and what is our earliest ancestor?? A Sponge! As easy as it may be to try to picture SpongeBob, it in fact was not. Sponges are much more like animals than they initially appear as they obtain their food by eating particles that drift into their spores. Sponges also share thousands of genetic markers with other animal species that are not seen in any nonanimal species. Cool! -
5750 BCE
And it Just Gets Better....Ediacaran Fauna!
about 575 million years ago, Ediacaran Fauna begin to emerge and boy are they an interesting looking group! These organisms can range from appearing like fronds, to geometrical disks, to blobs covered with tire tracks! This is when life really starts to get interesting. -
5410 BCE
Look its an Alien! Nope... Just a Cambrian.
541 to 511 million years ago, the first Chordate appeared which will later give rise to vertebrates.During this time, there were many first appearances of many living groups and life seemed to become more and more diversified. At a first glance, some of these creatures look so foreign (and creepy), they could be confused as extraterrestrial life. -
4800 BCE
And Then They Climbed Ashore
480 million years ago, the first invertebrate tracks are found on land, marking the beginning of life emerging from the water. The first vertebrate tracks were 390 million years ago. -
4750 BCE
Plants anyone?
475 million years ago, the earliest plants began to appear on the desolate land surrounding the life-filled sea. The earliest plants resemble moss and liverworts. These were the beginnings that gave rise to larger plants and eventually, complex forests. -
2980 BCE
Bring on the Dinos!
Around 298 million years ago, after life came ashore and continued to diversify and grow, the first amphibian-like creature was found and gave rise to some of the most interesting species: the dinosaurs. -
500 BCE
And Last But Most Certainly Not Least!
Only after the dinosaurs were gone were mammals able to start to evolve into drastic new forms. About 50 million years ago, the ancestors of whales evolved from land mammals into top predators of the ocean, bats emerged as the only flying mammals, and primates appeared! Not long after primates, about 7 million years ago, the oldest hominin were found--our closest relatives outside of chimpanzees!
