Post #2698923

The monkey and the block of yeast. I could have picked any animal, of course, but I think capuchin monkeys are a lot of fun and very distinctly unlike a block of yeast. Yeast is a fungus, and fungi and animals are more closely related to each other than either of them are to any plant. This much is well-established by molecular biology, and we actually share some surprising traits we've inherited from our distant common ancestors. Fungi and animals can store excess energy as glycogen (whereas plants use starch), both are also dependent on consuming other lifeforms for nutrients - and, oddly specifically, when either animals or fungi produce self-propelling cells (sperm cells and chytrid spores, respectively), those cells propel themselves with a single flagellum on the rear - in all other eukaryotes, such cells have one or more flagella on the front (basically working like a tiny propeller). While molecular biology has established the shape of the family tree, we've now gone *very* far back in time, and the fossil record is quite spotty. The earliest fossil that was evidently a kind of plant is about 1.5 billion years old, whereas the earliest ophistokonts (the group containing both animals and fungi) arose about a billion years ago.