The Avalon Explosion

The

Avalon explosion

The Pre-Cambrian Explosion

When

The Avalon Explosion happened around 575 million years ago in the Ediacaran period, which started at the end of the Cryogenian period 635 million years ago to the start of the Cambrian period 538 million years ago. Many scientists hypothesize that the explosion was triggered by the end of the Cryogenian peroid, summed up by this qoute from the PBS video "The Other Explosion you Should Know About"; "As [Cryogenian] glaciers retreated, huge amounts of nutrient-rich water from the melting ice flooded the oceans, causing mass blooms of oxygen producing cyanobacteria." With the rise of oxygen content in the oceans, life was able to bloom, hence the Avalon Explosion.

“Ediacaran.” Wikipedia, Wikimedia Foundation, 5 Feb. 2023, https://en.wikipedia.org/wiki/Ediacaran.

-Map of the Ediacaran Period

Reginald sprigg

In 1948, a geologist named Reginald Sprigg discovered one of the most important fossils to date in the Ediacara Hills of southern Australia. The fossil, which is of an animal called the Dickinsonia, eventually came to be thought as the oldest complex fossil to date; "Ediacara fossils [575 to 542 million years ago (Ma)] represent Earth's oldest known complex macroscopic life forms" - "The Avalon Explosion: Evolution of Ediacara Morphospace".

-About the Fossil

Life from the Avalon Explosion

As said in the previous slide, the Avalon Explosion is thought to be the first known existence of complex macrosopic life forms. However, what classification these "animals" fall under has been a topic of hot debate for years. A qoute from the article "Ancient steroids establish the Ediacaran fossil Dickinsonia as one of the earliest animals" sums this up quite well, "Ediacaran macrofossils are as “strange as life on another planet” and have evaded taxonomic classification, with interpretations ranging from marine animals or giant single-celled protists to terrestrial lichens." An example of this would be that some animals grew during this period with trilateral symmetry, which no animal or plant does today. Another example would be rangeomorphs growing by branching fractally, which means that they repeated a singular pattern over and over as they developed.

Geggel, L. (2016, January 12). Images: Bizarre, primordial sea creatures dominated the ediacaran era. LiveScience. Retrieved February 19, 2023, from https://www.livescience.com/53337-ediacaran-period-images.html

-What does it mean to grow fractally?

Bibliography

“Eons.” PBS, Public Broadcasting Service, 9 Mar. 2018, https://www.pbs.org/video/the-other-explosion-you-should-know-about-ijhtjf/.

The Avalon Explosion: Evolution of Ediacara Morphospace | science. (n.d.). Retrieved February 20, 2023, from https://www.science.org/doi/10.1126/science.1150279 (Library resource)

“Ediacaran.” Wikipedia, Wikimedia Foundation, 5 Feb. 2023, https://en.wikipedia.org/wiki/Ediacaran.

Ancient steroids establish the Ediacaran fossil - science | AAAS. (n.d.). Retrieved February 20, 2023, from https://www.science.org/doi/10.1126/science.aat7228