Microorganisms that expand their range by absorbing organelles
Nature, red in tooth and claw, is rife with organisms that eat their neighbors to get ahead. But in the systems studied by the theoretical ecologist Holly Moeller, an assistant professor of ecology, evolution and marine biology at the University of California, Santa Barbara, the consumed become part of the consumer in surprising ways.
Moeller primarily studies protists, a broad category of unicellular microorganisms like amoebas and paramecia that don’t fit within the familiar macroscopic categories of animals, plants and fungi. What most fascinates her is the ability of some protists to co-opt parts of the cells they prey upon. Armed with these still-functioning pieces of their prey, the protists can expand into new habitats and survive where they couldn’t before.
Watching them gives Moeller a distinctive view into the underlying structure of ecosystems today and the evolutionary forces that made them. The protists’ pilfering of organelles may seem bizarre, but the mitochondria in our own cells mark us as products of a related kind of metabolic acquisition by our ancient ancestors.
“In the broadest sense, these are questions about when and how organisms specialize, and how they can break that specialization by gaining access to something new,” she said. “To me, this work addresses questions about how organisms expand their ecological niche, how those acquisitions can be permanent, and what that means about how metabolism jumps across the tips of the branches of the trees of life.” [Continue reading…]