Researchers have identified things that look like strange creatures 550 million years ago, in a recent study.
The study, published in the journal Proceedings of the Royal Society, shows that group creatures from the Ediacaran era share genes with modern animals, including humans.
“None of them had heads or skeletons. Many of them may have looked like three-dimensional seabed baths, round discs that stood up, ”said Mairi Droser, professor of geology at UC Riverside.
“These animals are so strange and so different, it’s hard to assign them to parts of today’s organisms just by looking at them, and it’s not like we can take their DNA out – we can’t. ”
However, well-preserved fossil records have allowed Droser and first author in the study, recent UCR doctoral graduate Scott Evans, to link animal appearance and behavior to a genetic analysis of the living things. -currently.
The researchers considered four animals representing more than 40 known species identified since the time of Ediacaran, for the study.
These creatures ranged in size from a few millimeters to almost a meter long.
Kimberella were teardrop-shaped creatures with one broad, rounded head and one narrow head that tended to scrape the seabed for proboscis food. Later, they were able to move around using the “muscular leg” of today’s snails. The study included flat, oval-shaped Dickinsonia with a series of raised bands on their surface, and Tribrachidium, which spent its life motionless at the bottom of the sea.
Ikaria, recently discovered animals by a team like Evans and Droser, were also analyzed. They were about the size and shape of rice grains, and represent the first bilaterians – organisms with a front, back, and openings at each end connected by a slit. Evans said Ikaria apparently had a mouth, although these were not preserved in the fossil records, and were going through organic matter “eating as they went. ”
The four animals were heterogeneous, with different cell types. Most had symmetry on their left and right sides, as well as decentralized nervous systems and musculature.
In addition, they appear to have been able to repair damaged body parts through a process called apoptosis. The same genes are involved in key elements of human immune systems, which help in the elimination of viral and pre-cancerous cells.
The genetic components of these animals appear to have been dependent on the heads and sensory organs commonly found there. However, the complexity of interactions between these genes that would lead to such traits has not been achieved.
“The fact that we can say that these genes worked in something that has been extinct for half a billion years is fascinating to me,” Evans said.
The work was supported by a NASA Exobiology grant, and a Peter Buck postdoctoral fellowship.
Going forward, the team plans to conduct muscle development and functional studies to further understand the early evolution of animals.
“Our work is a way to put these animals on the tree of life, in some ways,” Droser said. “And show that they are genetically linked to today’s animals, and to us.”