The Origin of Life on Earth Is Weirder Than We Ever Imagined

Wednesday, 06 December 2017 - 2:38PM
Wednesday, 06 December 2017 - 2:38PM
The Origin of Life on Earth Is Weirder Than We Ever Imagined
Image credit: Unsplash
The origin of all living animals on earth was a sponge, according to the research of a University of Bristol biologist.

In a groundbreaking discovery, Dr. Davide Pisani, Professor of Phylogenomics at Bristol U, has announced that sponges (phylum Porifera) are the sister group of all other animals and provide further evidence that Ctenophora-sister represents a tree reconstruction artifact.

Using new statistical methods, Pisani and his team took a look at the evolutionary models commonly used in phylogenetics (the study of evolutionary relationships between biological beings) to see if the genomic equations relating to early animal evolution played out—they found that the data reveals the sponge the proper root of the animal tree, at the same time failing to give such a nod to the comb jelliesm, which some scientists have long believed were the original ancestor of all life on Earth. 

 
"The relationships at the root of the animal tree depend on model adequacy, with Ctenophora-sister (jellies) emerging more prominently when the data are modeled less adequately and Porifera-sister (sponges) being better supported when the data are more adequately modeled… we conclude that Porifera-sister better represents the phylogenetic signal in the data," Pisani said.
 
Although animal life has since taken radical leaps since it first began as, Pisani's team has deduced, sponges, it's still critical to know where it all started.

"The fact is, hypotheses about whether sponges or comb jellies came first suggest entirely different evolutionary histories for key animal organ systems like the nervous and the digestive systems," Pisani said

In other words, correctly knowing how the tree of life branches out helps to better understand evolution of bigger animals, including us. 

Not only that—having a better understanding of how evolution works on Earth will only help us broaden our knowledge of how evolution works in general as we continue to spread beyond the confines of our planet and explore the solar the system. 
 
Science
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