How competition shaped our family tree

A cast of the skull of Homo Heidelbergensis, one of the hominin species analyzed in the latest study. Credit: The Duckworth Laboratory/University of Cambridge.

Did you know that competition between species played a huge role in shaping our family tree?

A new study from the University of Cambridge suggests that it wasn’t just climate that determined which hominin species thrived and which ones vanished—it was also about who they had to compete with.

For most animals, finding their place in the world means filling certain roles, like Darwin’s finches adapting their beaks for different foods.

When those roles are taken, competition heats up, and new species struggle to emerge while others face extinction. This is true for many animals, from birds to mammals.

But what about us, Homo sapiens? Well, it turns out our story is quite unusual. While most species reach a point where new species stop popping up and extinction rates rise, for Homo, it was different.

The more Homo species there were, the more new ones seemed to appear—a strange twist in the evolutionary tale.

Think of it like this: imagine an island full of different kinds of beetles. As more types of beetles emerge, the rate of new species creation increases instead of slowing down. That’s similar to what happened with Homo species.

This pattern puzzled researchers like Dr. Laura van Holstein, who led the study. They looked at fossils from various hominin species, like Homo erectus and Homo habilis, to understand how they evolved over millions of years.

By analyzing these fossils, they could figure out when each species emerged and when it disappeared.

But fossils can be tricky. Sometimes, we might miss fossils from certain time periods or places, which can skew our understanding of a species’ lifespan. Dr. van Holstein used clever techniques to fill in these gaps and get a clearer picture.

Surprisingly, they found that some species didn’t slowly morph into others, as previously thought. Instead, new species branched off from existing ones—a bit like how new branches grow on a tree. This means more species coexisted at the same time, possibly competing for resources.

So, what caused this burst of new Homo species? It seems technology played a big part. Unlike other animals, Homo species were clever with tools and hunting techniques. This allowed them to adapt quickly to new environments and carve out their own niches.

And then came Homo sapiens—the ultimate generalists. With our advanced technology and ability to adapt, we outcompeted other Homo species. It’s like we were the superheroes of evolution, able to thrive in almost any environment.

This study teaches us something important: competition was a driving force in human evolution. And our story is unlike any other in the animal kingdom. It’s a reminder of how adaptable and innovative our ancestors were—and how these traits shaped the course of our evolution.