Question: Did worms have the same molecules as we evolved from them?

Anthony Redmond answered on 8 Jan 2019: last edited 8 Jan 2019 3:52 pm

Actually, we didn’t evolved from worms! Certainly not from any worm like those that you can see alive today! What traits our common ancestors with worms possessed is still under intense debate among scientists. However, it’s probably fair to say that some of our ancient animal ancestors looked and acted more like worms than like humans!

Interestingly, worms have evolved multiple times, usually from far more complex ancestors! This might be because their body shape is streamlined, and well adapted. However, the same could be said of animals with legs (spider and humans legs evolved separately!), or fins (think how much a dolphin, which evolved from land mammals, looks like a shark!).

Because most worms are much more simple than us, and have much shorter life spans, they typically evolve much faster than us, and have removed many genes from their genomes that their ancestors would have had. These genes are presumably no longer needed for their simplified forms. As a result of this. Genetically, and in terms of protein molecules, humans are actually more like our shared ancestors with worms than most modern worms are!

For parasitic worms this is even more so the case, as they evolve fast to avoid host defences, and often remove genes associated with survival outside of a host.