The latest news out of biology (well, it’s been building for quite a long time) is that the tree of life is very different from how we thought it was. The bit that got me excited?
In the new vision — based on increasingly sophisticated genetic analyses — people and other animals are closer cousins to single-celled choanoflagellates than to other multicellular organisms. Giant kelp that grow as wavering undersea forests off the California coast are closer relatives to single-celled plankton called diatoms than to multicelled red seaweeds or plants.
This is because it obliterates the notion that multicelluarity evolved only once. In fact, Wikipedia claims “complex multicellular organisms evolved only in six eukaryotic groups: animals, fungi, brown algae, red algae, green algae, and land plants. It evolved repeatedly for Chloroplastida (green algae and land plants), once or twice for animals, once for brown algae, three times in the fungi (chytrids, ascomycetes and basidiomycetes) and perhaps several times for slime molds, and red algae.” This is cool because it removes one of the bottlenecks for intelligent life: The chances of life spontaneously evolving are vanishingly small (once that we know of), and the chance of eukaryotic life developing is also vanishingly small (once that we know of). However, where in the past it was thought* that multicellularity evolved only once, now it seems a common, and therefore inevitable, occurrence.
Which means, if we do find extraterrestrial life, it will almost certainly be multicellular in some way.
*At least by me, and it seemed to be the general thought when I went through uni 20 years ago. I don’t know how long scientists dedicated to the field have been aware of this.
For more alien life science, see Life In Cryogenic Conditions.