Section 1.1: The Discovery of Ancient Cooking

Archaeologists have identified the oldest evidence of fire being used to cook food, with remains of a massive carp discovered, dating back nearly 800,000 years in Israel. This significant find highlights early culinary practices.

Section 1.2: Ediacaran Fauna's Diet

What did some of the earliest animals consume? The revelations about the nutrition of ancient creatures are equally captivating. Certain species were true gluttons, and recent studies from the Australian National University (ANU) reveal that the final meals of animals living over 550 million years ago offer new insights into the physiology of these primitive beings.

The focus here is on the Ediacaran fauna, which thrived around 575 million years ago. A recent article in the journal Current Biology presents new, previously unknown details about how these organisms fed and digested nutrients. The fossils of Ediacaran fauna are the oldest visible remnants of their type, standing apart from earlier microscopic fossils.

Subsection 1.2.1: The Role of Phytosterols

Researchers at ANU investigated fossils that contained phytosterol molecules, which are sterols produced by fat-rich plants such as sunflower, pumpkin, and sesame seeds. The presence of these molecules in fossilized remains indicated that an organism named Kimberella possessed a mouth and intestines, allowing it to digest food much like modern animals. This snail-like creature was considered one of the most advanced organisms during the Ediacaran period, which lasted from approximately 635 to 541 million years ago.

Professor Jochen Brocks, a co-author of the study, suggested that nutrient-rich algae might have significantly contributed to Kimberella's growth. However, not all creatures from that era fed similarly. Another species, Dickinsonia, lacked both a mouth and intestines and absorbed nutrients through its body while moving across the ocean floor. Adult Dickinsonia could grow to impressive lengths of up to 1.4 meters.

Dickinsonia — [Photo: Verisimilus at English Wikipedia, CC BY-SA 3.0, via Wikimedia Commons]

Section 1.3: Insights from Fossil Analysis

Fossils of both Kimberella and Dickinsonia were discovered in 2018 along the cliffs of Russia's White Sea. Using sophisticated chemical analysis techniques, scientists extracted and examined the sterol molecules preserved in the fossilized tissues. This research confirmed that these fossils belong to some of the earliest known ancestors of modern animals, revealing their diets included bacteria and algae found on the ocean floor.

Professor Brocks noted that one of the most challenging aspects of this study was distinguishing between fat particles from the organisms and remnants of algae and bacteria found within their intestines.

“Only after examining Kimberella’s intestinal particles were we able to ascertain precisely what it consumed and how it processed its food. Kimberella exhibited a remarkable ability to identify beneficial sterols and had a finely tuned gut designed to filter out the rest,” the co-author explained.

The analysis revealed the contents of these ancient animals' intestines, even in a digested state, and confirmed that Dickinsonia lacked intestines altogether.

Source: Current Biology