"Vampiric" Microbes May Have Initiated Billion-Year-Old Evolutionary Leap

The modern-day equivalent of the ancient primitive predator, this Vampyrella amoeba is seen here sucking out the innards of its green algae target. Norbert Hulsmann/Flickr; CC BY-NC-SA 2.0
Robin Andrews 23 Nov 2015, 19:36

Vampires aren’t mythical creatures. Lampreys, bats and even one of Darwin’s famous Galapagos finches engage in vampirism, along with hundreds of other parasitic worms, mammals, and even snails. Almost a billion years ago, back before there was even blood, it seems that some very primitive forms of life still accessed the nutritious innards of other organisms through violent punctures: At the Geological Society of America’s annual meeting in Baltimore, paleontologists announced they have found evidence suggesting the existence of a microscopic, 750 million-year-old “vampire” that did just that. 

Eukaryotes, one of the major domains of life, are organisms whose cells contain a nucleus (among other things) enclosed by a membrane. Susannah Porter, a paleontologist at the University of California, was examining 750 million-year-old microscopic eukaryotic fossils from the Grand Canyon using a powerful scanning electron microscope when she noticed that several of them had clean-cut puncture holes in their cell walls. These punctures were always approximately the same size, suggesting that something had deliberately and repeatedly caused them – perhaps a predator, albeit a very simple, microscopic one.

As it turns out, scientists know that some amoebas still do this today. The appropriately named Vampyrella ulothrichis attaches itself to strands of Ulothrix, wherein it pierces the cell walls with the help of enzymes, before it vacuums out its insides. This seems likely to be the same mechanism that the eukaryotes’ predator employed, although for now, the researchers cannot be sure: a fossil of this predator has yet to be found, so this is purely speculative.

If a predator evolves a new mechanism that allows it to hunt prey effectively, more prey will be consumed. This evolutionary pressure on the prey may lead it to evolve something that will help it outrun its predator, subsequently meaning more prey will live. Either way, this evolutionary pattern – known as the Red Queen hypothesis – dictates that organisms must constantly adapt and evolve when faced with a threat to their existence.

Very primitive organisms were no different. Eukaryotes evolved around 1.8 billion years ago, but they did not appear to rapidly evolve, developing skeletons and other defensive traits, until around a billion years later. Without any natural environmental threats, an organism barely needs to change, which included these billion-year-old eukaryotes. The shark is a great example of this: This fearsome apex predator, relatively unchanged over time, has been around for over 400 million years.

However, the evolution of predators may have forced these primitive eukaryotes to evolve to “outrun” them, initiating the rapid diversification of life that occurred during the Ediacaran period around 600 million years ago. This ancient form of predation on simple eukaryotic cells, if verified, is therefore a remarkable piece of evidence.

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