A new study might have solved the age-old mystery of how the first animals evolved on our planet, therefore leading the way for more advanced creatures and eventually the rise of humans.
According to a news release from the Australian National University, a team of scientists led by associate professor Jochen Brocks gathered ancient sedimentary rocks from a location in central Australia, hoping to figure out how early life forms evolved in Earth’s nascent years. After crushing the rocks into powder and extracting molecules belonging to these early life forms, Brocks and his colleagues discovered what could have helped the world’s first animals evolve during that crucial time in our planet’s history.
“These molecules tell us that it really became interesting 650 million years ago. It was a revolution of ecosystems, it was the rise of algae,” said Brocks in a statement.
As further explained by the Washington Post, Earth was engulfed by ice some 700 million years ago, due to an event scientists refer to as “Snowball Earth.” And while Earth got a brief respite through a series of volcanic eruptions that had released carbon dioxide into the atmosphere and caused global warming, the warming also went out of control, turning our planet into a virtual greenhouse with boiling-hot oceans and a massively flooded landscape. This warming period was then followed by yet another “snowball” period.
The above scenario points to a very chaotic time during the Cryogenian period, a time that would normally not be conducive for the evolution of organisms. But the Washington Post noted that this is when the first animals truly began to evolve.
According to study leader Brocks, the melting of “Snowball Earth” during the above global heating event sent “torrents of nutrients” into the ocean. As global temperatures began to cool down to reasonable levels, this change in the world’s climate resulted in an ideal situation for algae to spread. This all led to the evolution of bacterial life in the ocean into complex creatures, said Brocks.
“These large and nutritious organisms at the base of the food web provided the burst of energy required for the evolution of complex ecosystems, where increasingly large and complex animals, including humans, could thrive on Earth.”
Algae, according to the Washington Post, had first appeared about one to two billion years ago, but it wasn’t until Snowball Earth melted that it truly became abundant to the point that it could sustain a large number of microscopic organisms.
As the sedimentary rocks found by Brocks and study co-leader Dr. Amber Jarrett could be traced to a time right after the melting of Snowball Earth, the researchers believe that this cataclysmic event was directly involved in how the first animals evolved on Earth, with the bacteria that existed billions of years prior finally being joined by more advanced, multicellular creatures.
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