Did earliest animal ecosystems play a role in the evolution of complex life? | Knowledge News


A study involving the University of Cambridge has used virtual recreations of the earliest animal ecosystems or marine animal forests that demonstrate the part they played in the evolution of planet Earth. Let us know more about it.

Marine animal forests may have impacted the distribution of nutrients in the oceans (Photo credit: National History Museum)

New Delhi: A recent study found that the first animal communities could have significantly impacted how complex life evolved over 550 million years ago. Earth’s first animals or sea creatures may seem simple compared to present-day species, but they had a considerable impact on the explosion of life on our planet more than half a billion years ago. Let us learn more about the study.

What the research says

New research by the University of Cambridge, UK, suggests that complex ecosystems emerged during a specific period in Earth’s history called the Ediacaran, which is characterised by the emergence of the first complex, multicellular organisms.

About Ediacaran period

The Ediacaran period, a time of monumental significance in Earth’s history, began 635 million years ago. It marked the emergence of the first complex, multicellular organisms, which eventually evolved into the diverse array of animal species we see today, starting around 580 million years ago.

The Ediacaran period, a captivating chapter in Earth’s history, remains mysterious. It witnessed the emergence of numerous bizarre species, enigmatic creatures that seemingly appeared out of nowhere in Ediacaran oceans, only to vanish without a trace. This period was a time of intense evolutionary experimentation, a puzzle that intrigues scientists and enthusiasts alike.

As per research, Ediacaran ended about 540 million years ago after a sharp drop in biological diversity, which refers to the variety and variability of life on Earth. This decline in diversity marked a significant shift in the evolution of life on our planet.

End of the Ediacaran

The end of the Ediacaran period, which saw the emergence of the first complex, multicellular organisms, coincides with the beginning of the “Cambrian explosion”. The appearance of most major animal phyla marked this period of rapid diversification of life forms. The researchers initially looked for evidence of a theorised mass extinction event 550 million years ago that led to the sudden decline in biodiversity in the dying days of the Ediacaran, paving the way for the Cambrian explosion.

What were these marine animal forests like?

The fossils used in this study were found at Mistaken Point in Newfoundland, Canada, a UNESCO World Heritage Site. The fossils were preserved in their original positions after being buried in volcanic ash, making the site a kind of ‘Ediacaran Pompeii’. This unique preservation allowed researchers to gain valuable insights into the early animal communities and their impact on the evolution of life.

Marine animal forests, a term coined to describe the dense aggregations of early animals, include familiar ecosystems, such as coral reefs, that support a high level of biodiversity by supplying nutrients, structure, and shelter to other organisms. Unlike modern coral reefs, these ancient marine forests were primarily composed of soft-bodied organisms that formed complex three-dimensional structures on the seafloor.

The fossils unearthed from Mistaken Point are a testament to the diversity and complexity of early life. They consist of multiple branching ‘fronds,’ initially resembling plants. However, recent research has revealed that these structures are, in fact, animals. The largest of these stands several tens of centimetres tall, forming dense canopies akin to an underwater forest.

These early animals lived in a relatively deep water environment (below the depth to which light can penetrate) on the seafloor. The seafloor was likely covered in microbial mats similar to those in extreme environments today.

But no larger animals were swimming around, as seen in modern oceans.

Did these early sea creatures impact life on Earth?

With the disruption of water flow, an Ediacaran community could have impacted the distribution of important resources like food and oxygen. This disruption, possibly caused by geological or environmental changes, could have profoundly affected the survival and evolution of these early animal communities.

This disruption in water flow may have impacted animal communities as well. Slowing the water flow around them may have enabled them to feed or respire better. It also could have had an impact by contributing to the oxygenation of the oceans, increasing oxygen availability to marine animals. This increase in oxygen helped marine animals carry out more complicated modes of life, potentially leading to key innovations such as the evolution of predation.

The research also shows that entirely new lifestyles and behaviours appeared as animals became more complex and started interacting. These changes in behaviour and lifestyle were crucial in the evolution of life, as they allowed for more efficient use of resources and increased the adaptability of these early animal communities.

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