For one thing, it turns out they have organelles, not like the textbooks used to say:
As the evolutionary story is usually told, first came the prokaryotes: the archaea and bacteria, which are often envisioned as simple bags of enzymes without an intricate structure. Then, more than 1.5 billion years ago, eukaryotes evolved, marking the advent of unprecedented cellular complexity and permanently transforming life on Earth, allowing for the rise of animals, plants, fungi and protists. The eukaryotes represented a substantial departure from their predecessors, and the transition from an all-prokaryote world to one that contained eukaryotes is often described as abrupt and explosive.
But this version of events ignores the fact that, for the past few decades, researchers have been quietly uncovering many complex structures within prokaryotes, including membrane-bound organelles. In contrast to eukaryotes, which all have a suite of organelles in common, different groups of prokaryotes showcase their own specialized compartments. One kind of bacterial organelle, discovered in 1979, is essentially a little magnet wrapped in a lipid package; another hosts a series of reactions crucial for energy metabolism; still others serve as small storage units for nutrients. And that list is only growing as scientists discover more and more compartments within supposedly simple bacterial cells. “Bacteria are a lot more complex, in other words, and may have a lot more similarities in their biology to eukaryotes than people have assumed in the past,” said John Fuerst, a microbiologist at the University of Queensland in Australia. The very existence of organelles in these bacteria, coupled with intriguing parallels to the more familiar ones that characterize eukaryotes, has prompted scientists to revise how they think about the evolution of cellular complexity — all while offering new ways to probe the basic principles that underlie it.
Jordana Cepelewicz, “Bacterial Complexity Revises Ideas About ‘Which Came First?’” at Quanta
Back on the early Earth, kids, natural selection acting on random mutation moved faster than the speed of light, so as to make all this possible… Believe or flunk!
Hat tip: Philip Cunningham