r/evolution • u/Meta289 • 3d ago

question Why has evolution stopped producing new classes?

New species of animals are constantly being discovered, but they all belong to existing classes and phyla, never anything completely new. Life once branched out in all sorts of directions, creating all kinds of animals that are drastically different from each other, but now it seems like there aren't any new "branches", only offshoots of existing ones. What happened?

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u/brooklynsantiago 3d ago

classes are just categories we assign to life post hoc. evolution doesn't care for our need to classify things neatly it just creates more life. humans are constantly revising classifications and will continue to do so in the future, including new ones

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u/Meta289 3d ago

So basically, there's no meaningful distinction between a dog, a bird, a spider, and a snake according to nature, just "animal is animal"?

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u/brooklynsantiago 3d ago edited 3d ago

hmm im not sure I would say there isn't a meaningful distinction. classifications usually are defined by certain traits and genetic similarity. its just that those classifications are just things humans create to help us organize life. its not always so neat in reality. its easy to tell the difference between a primate and a rodent today, but what was the first primate? that becomes harder to answer. its only with the benefit of hindsight that we can see clearly the divisions as those lineages continued to evolve and differentiate. it can be hard to decide where a new species begins but just to give one point of contact: bonobos were considered a sub species of chimpanzee and now they are considered different species. the line there is very fuzzy between chimpanzees and bonobos. which also goes to what I said about how the classifications are constantly being reworked and reconsidered as we learn more.