What types of animals first existed on Earth long ago? This is what a recent study published in the Proceedings of the National Academy of Sciences hopes to address as a team of scientists investigated the chemical and physical compositions of the first animals on Earth. This study has the potential to help researchers better understand how early life formed on Earth and how life evolved to what we see today.
For the study, the researchers examined chemical fossil records estimated to be more than 541 million years old for evidence of what living organisms existed during that time. The researchers analyzed core samples obtained from around the world, including Siberia, western India, and Oman to better understand their chemical compositions. This study builds on a 2009 study from the same team of researchers that conducted the exact same research, but questions began to arise about their results. This most recent study reaffirms that first study regarding the first animals on Earth were likely sponges living in the oceans of ancient Earth.
“We don’t know exactly what these organisms would have looked like back then, but they absolutely would have lived in the ocean, they would have been soft-bodied, and we presume they didn’t have a silica skeleton,” said Dr. Roger Summons, who is a Schlumberger Professor of Geobiology Emeritus at the Massachusetts Institute of Technology and a co-author on the study.
Scientists estimate that the first lifeforms appeared on the Earth between 4.3 and 3.8 billion years ago. However, due to the Earth’s geological processes, specifically plate tectonics, obtaining fossils from this period is incredibly rare. Therefore, studies like this demonstrate that fossils only a tenth the age of the Earth can help scientists better understand the formation and evolution of life on our planet.
What new discoveries about the first animals on Earth will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: Proceedings of the National Academy of Sciences, EurekAlert!