“Now, when we explore animal origins, we shift our perspective from the sky, to the local daily conditions on the shallow marine settings. And how stressful they were. This means that we look more closely at potential biological adaptations rather than a chemical one, like higher oxygen in the atmosphere, to explain the rapid rise of animals at this time,” says Emma Hammarlund, associate professor of geobiology at Lund University and first-author of the study.
The team’s research explores how these daily swings between oxic and anoxic conditions shaped the selection of key cellular mechanisms for early animal life - organisms with tissues, organs, and an advanced regulation of cell stemness and differentiation - to handle stress. For example, one of the key cellular mechanisms they identified, against oxygen stess, can also regulate developmental processes and the fate of cell immaturity.
“We now have evidence that fluctuating oxygen levels between night and day might have influenced the very foundation of animal life, providing a new perspective on how cellular mechanisms could offer both a way to cope with oxygen stress and regulate the work of cells and tissues. To invoke a biological trigger for the rise of animals could inform our understanding of the evolutionary origin of stem cells and other cellular functions,” Emma adds.
Their work adds to our growing understanding of how environmental factors, like stress and oxygen variability, could drive biological adaptations over evolutionary time.
“At the end of the day, a key secret to being a large animal that lives for up to 100 years is the way we handle continuous tissue renewal through the few, but extremely important, stem cells. We have not yet figured out the secret on how this evolved or even how it functions today,” notes Emma Hammarlund.
In her accompanying article for The Conversation, Emma shares more about the broader implications of these findings. She explores how oxygen dynamics may have shaped the development of early animal life, laying the foundation for the biological processes that support the complex organisms that exisit on Earth today.
Read more in Emma's full article in The Conversation:
How dramatic daily swings in oxygen shaped early animal life – New Study
