Oct 22, 2024 06:00 PM
https://www.sciencenorway.no/animal-king...ay/2421079
EXCERPTS: “There’s a market out there for something like this,” says Anette Högström, a geologist at The Arctic University Museum in Tromsø. [...] “Northern Finnmark is one of the very few places in the world where we know it’s possible to find fossils from around 600 million years ago,” she says.
Högström says that their research involves small creatures. Instead of animals and plants, she and her colleagues talk about ‘eukaryotic organisms.’
[...] 800 to 600 million years ago – multicellular life arrived on the scene. ... The oldest known fossils of multicellular organisms that are not algae date from the Ediacaran Period, about 600 million years ago. “That was when the first animal life appeared,” Högström says.
[...] Recently, scientists made another spectacular fossil discovery that may offer answers to what happened to life on Earth during the dramatic period called Snowball Earth. ... Our Earth might even have gone into a deep freeze twice – first around 720 million years ago and then again around 650 million years ago.
But experts on the first life on Earth are divided into two opposing camps.
One group of researchers believe that the precursors to animal life somehow managed to survive the Snowball Earth events and that the very first ‘animals’ are the forerunners of all later animal life – and humans.
The other group of scientists believe that animal life could not have survived millions of years in this deep freeze, and that the animals must have arisen again, some 600 million years ago.
[...] “The discoveries we made last summer have enabled us to compare fossils from before, during and after the Snowball Earth events.”
[...] In short, Högström and her colleagues observed that life during Snowball Earth went from more complex organisms – eukaryotic microorganisms – and back again to simpler organisms like bacteria. [...] “Our fossil findings also show that bacteria take over during Snowball Earth.”
[...] The ‘animals’ that disappeared some 650 million years ago are thus completely different from all animal life that exists today. ... Högström and her colleagues have now found that traces of the eukaryotic organisms in Finnmark disappeared during Snowball Earth and were replaced by bacteria.
So another possibility is that the first strange animal life—which may have appeared either before the Snowball Earths or in the period between the two Snowball Earths— simply disappeared. Another animal life then returned several million years after the last Snowball Earth.
But yet another study has been published just within the last few weeks, this time from researchers in Brazil. It concludes that the forerunners of animals and plants may have existed as much as 800 million years ago – and that these earlier ‘animals’ and ‘plants’ survived both of the two dramatic Snowball Earth events.
[...] About a hundred million years after the last Snowball Earth melted, life on Earth underwent something even more dramatic 539 million years ago. The Cambrian explosion burst onto the scene.
In less than 20 million years, a great deal of life on Earth as we know it today appeared. Some researchers believe that the process moved along even faster.
[...] Högström points out that Snowball Earth may have helped to bring about the Cambrian explosion. [...] “What seems certain is that the increased amount of oxygen on Earth must have helped lay the foundation for the explosion of animal life,” she says.
Högström believes that the discussion about whether the first animal life managed to survive Snowball Earth depends a lot on whether there really were open ocean areas during these extreme ice ages. And – whether there were organisms that carried out photosynthesis in these ocean regions and could thus become food for the animals.
EXCERPTS: “There’s a market out there for something like this,” says Anette Högström, a geologist at The Arctic University Museum in Tromsø. [...] “Northern Finnmark is one of the very few places in the world where we know it’s possible to find fossils from around 600 million years ago,” she says.
Högström says that their research involves small creatures. Instead of animals and plants, she and her colleagues talk about ‘eukaryotic organisms.’
[...] 800 to 600 million years ago – multicellular life arrived on the scene. ... The oldest known fossils of multicellular organisms that are not algae date from the Ediacaran Period, about 600 million years ago. “That was when the first animal life appeared,” Högström says.
[...] Recently, scientists made another spectacular fossil discovery that may offer answers to what happened to life on Earth during the dramatic period called Snowball Earth. ... Our Earth might even have gone into a deep freeze twice – first around 720 million years ago and then again around 650 million years ago.
But experts on the first life on Earth are divided into two opposing camps.
One group of researchers believe that the precursors to animal life somehow managed to survive the Snowball Earth events and that the very first ‘animals’ are the forerunners of all later animal life – and humans.
The other group of scientists believe that animal life could not have survived millions of years in this deep freeze, and that the animals must have arisen again, some 600 million years ago.
[...] “The discoveries we made last summer have enabled us to compare fossils from before, during and after the Snowball Earth events.”
[...] In short, Högström and her colleagues observed that life during Snowball Earth went from more complex organisms – eukaryotic microorganisms – and back again to simpler organisms like bacteria. [...] “Our fossil findings also show that bacteria take over during Snowball Earth.”
[...] The ‘animals’ that disappeared some 650 million years ago are thus completely different from all animal life that exists today. ... Högström and her colleagues have now found that traces of the eukaryotic organisms in Finnmark disappeared during Snowball Earth and were replaced by bacteria.
So another possibility is that the first strange animal life—which may have appeared either before the Snowball Earths or in the period between the two Snowball Earths— simply disappeared. Another animal life then returned several million years after the last Snowball Earth.
But yet another study has been published just within the last few weeks, this time from researchers in Brazil. It concludes that the forerunners of animals and plants may have existed as much as 800 million years ago – and that these earlier ‘animals’ and ‘plants’ survived both of the two dramatic Snowball Earth events.
[...] About a hundred million years after the last Snowball Earth melted, life on Earth underwent something even more dramatic 539 million years ago. The Cambrian explosion burst onto the scene.
In less than 20 million years, a great deal of life on Earth as we know it today appeared. Some researchers believe that the process moved along even faster.
[...] Högström points out that Snowball Earth may have helped to bring about the Cambrian explosion. [...] “What seems certain is that the increased amount of oxygen on Earth must have helped lay the foundation for the explosion of animal life,” she says.
Högström believes that the discussion about whether the first animal life managed to survive Snowball Earth depends a lot on whether there really were open ocean areas during these extreme ice ages. And – whether there were organisms that carried out photosynthesis in these ocean regions and could thus become food for the animals.