Ediacaran Explosion: The Dawn of Animal Life on Earth

Dickinsonia: An Early Animal

Scientists have long debated whether Dickinsonia, a strange organism that lived during the Ediacaran period (541-520 million years ago), was actually an animal. Now, a new study provides definitive evidence that it was.

Cholesterol in Dickinsonia Fossils

The study, published in the journal Nature Ecology & Evolution, analyzed fossils of Dickinsonia and found traces of cholesterol. Cholesterol is a molecule that is only found in animals, so its presence in Dickinsonia proves that the organism was an animal.

Diversification of Animal Life

The Ediacaran explosion, which began 575 million years ago, marked a dramatic increase in the diversity of animal life on Earth. This period saw the emergence of modern bird groups, whales, and lagomorphs (rabbits and hares).

Sponges: The First Branch

One of the first major splits in animal evolution occurred between sponges and all other animals. Sponges are simple, filter-feeding organisms that lack the specialized cells and tissues that characterize other animals.

Conclusion

The Cambrian explosion, which began 545 million years ago, is often celebrated as the beginning of animal life on Earth. However, the Ediacaran explosion, which came before it, was just as important. It was during this time that the first animals evolved and began to diversify, eventually giving rise to the complex and varied animal life that we see today.