A claim today that humans evolved from worms is based on scientists discovering a proto-backbone in the world’s oldest worm fossil.
However as with all great science news headlines, it’s never as simple as those seeking funding and the news media who report the discoveries try to make it.
The assumption is made that “because” creature A has a feature that creature C has, creature A “must” have evolved into creature C. Yet biologists have long known that nature repeatedly throws up examples of similar creatures that look the same (bees and wasps, for example) but who don’t share common ancestors.
The phenomenon is known as “convergent evolution“, and is often expressed:
A -> B
C -> B
A feature “B”, such as a spine in this instance, may have developed separately in vastly different organisms (A and C). The discovery of a proto-backbone in an ancient fossil therefore does not prove an evolutionary pathway to anywhere.
The picture of sharks and dolphins shows the body form of totally unrelated species can be explained simply by adaptation, not inheritance.
Yet ‘humans evolved from worms” still makes a great headline, and you wouldn’t be reading this if it didn’t.
For more on this story see this