Scientists believe they may have identified the first animal to have roamed the Earth about 700 million years ago, a new study published in Nature revealed.
Researchers determined that the first animal was likely a comb jelly, or ctenophore — a predator that travels through the ocean in search of food, according to a news release about the study from the University of California Berkeley.
Although they look like jellyfish, the comb jellies have cilia, not tentacles, to propel them through water. Today, they are a part of our marine ecosystem and can be seen in all kinds of waters.
“The most recent common ancestor of all animals probably lived 600 or 700 million years ago. In a press release, Daniel Rokhsar said that it’s difficult to tell what these animals were like, because they had soft bodies and left no fossil records. “But we can use comparisons across living animals to learn about our common ancestors.”
There has long been a debate on which animal came first — the ctenophore or the sponge, the university said. Sponges are creatures that spend most of their lives in one spot, filtering water through their pores to collect food particles.
Many people have claimed that the sponge was the first creature to evolve, before the ctenophore. This is not true, according to researchers. Researchers have determined that sponges were not the first to appear, but they came second.
In order to make that determination, scientists looked at the organization of genes in the chromosomes of the organisms. The chromosomes of the ctenophore look very different than the chromosomes of sponges, jellyfish and other invertebrates — alerting researchers that the ctenophore could have either come much earlier than the others, or much later.
“At the beginning, it was difficult to tell whether ctenophore’s chromosomes differed from other animals’ chromosomes because of their rapid evolution over millions of years,” Rokhsar said in a news release. “Alternatively, they could be different because they branched off first, before all other animal lineages appeared. We needed to figure it out.”
The “smoking gun” for researchers was when they compared the chromosomes of ctenophores to non-animals.
“After comparing the chromosomes between these animals, the researchers found that sponges, and some other animals, had chromosomes rearranged differently.
According to researchers, the new insight is valuable to learning about the basic functions of all animals and humans today, such as how we eat, move and sense our surrounding environment.
Simrin Singh is a social media producer and trending content writer for CBS News.
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