Evolving evolution: How life learns to adapt better

Evolution has shaped life on Earth for billions of years. Organisms adapt to their surroundings, developing traits that help them survive. From bacteria resisting antibiotics to viruses mutating to evade vaccines, evolution is always at work. But what if evolution itself could change over time?

A new study from the University of Michigan (U-M) explores this very idea. The research suggests that evolution does not just happen – it improves itself. The ability to evolve, known as “evolvability,” might be something that organisms can enhance over generations.

Luis Zaman, an evolutionary biologist at U-M and the study’s lead author, finds this concept fascinating.

“Life is really, really good at solving problems. If you look around, there’s so much diversity in life, and that all these things come from a common ancestor seems really surprising to me,” said Zaman.

“Why is evolution so seemingly creative? It seems like maybe that ability is something that evolved itself.”

Evolution of the potential to adapt

Most evolutionary theories focus on how mutations increase an organism’s fitness in its environment. A beneficial mutation gives an organism a survival advantage, helping it pass those traits to future generations.

However, evolvability is different. It does not focus on immediate fitness. Instead, it increases an organism’s potential to adapt to new challenges in the future.

“This forward-looking feature of evolvability makes it contentious,” Zaman said. “We think it’s important. We know it happens. Why it happens and when it happens is something we’re less clear about. We were trying to figure out: Can we see the evolution of evolvability in a more realistic computational model?”

To answer this question, the researchers designed an experiment to simulate evolution. They wanted to explore whether populations could develop an improved ability to evolve when faced with changing environments.

Building a model to test evolution

To test their hypothesis, the researchers built a computational model using logic functions. They compared the model to a population that could only consume certain types of berries.

In one environment, red berries were beneficial, while blue berries were toxic. In another, the roles reversed. A population could only thrive in one of these two conditions at a time.

They ran two different scenarios. In one, the environment remained stable, meaning a population only had to adapt once. In another, the environment changed regularly, forcing the population to shift between eating red and blue berries.

The goal was to observe how populations adapted under these different conditions and whether their ability to evolve improved over time.

Environmental change boosts evolvability

The results revealed something remarkable. Populations exposed to shifting environments showed a significant increase in evolvability. Instead of becoming specialists in one condition, they developed traits that allowed them to survive in both.

Mutations increased a thousandfold in populations that had to switch between eating red and blue berries. This meant that organisms were not just adapting to their current surroundings – they were also developing the ability to adapt to future changes more efficiently.

The key takeaway was that exposure to varying conditions could push populations to evolve in a way that made them better at evolving itself. This supports the idea that evolvability is not just a byproduct of evolution but a trait that natural selection can shape over time.

Role of mutational neighborhoods

The researchers used a computational system called Avida to simulate evolutionary processes. This system allowed them to track how populations changed in response to fluctuating environments.

“You can think of the evolved computer programs as pathways of multiple genes made up of computer codes,” said Zaman. “Each time the environment fluctuates, this pathway needs to be reconfigured to eat the new berries.”

Mutational neighborhoods played a crucial role in this process. These neighborhoods represent genetic variations that allow populations to shift their survival strategies. Instead of relying on entirely new mutations, organisms could modify existing genetic pathways to adapt more quickly.

By studying these genetic shifts, the researchers gained deeper insights into how organisms adjust to unpredictable environments. Rather than starting from scratch each time, populations could “learn” how to evolve more efficiently.

Impact of time on evolvability

The researchers also investigated how the timing of environmental changes influenced evolvability. They tested three different scenarios: one where environments changed every generation, one where they changed every ten generations, and another where they changed every hundred generations.

The results showed that when environments changed too quickly, populations struggled to develop evolvability. However, even long cycle periods – hundreds of generations – could lead to significant improvements in an organism’s ability to adapt.

“Once a population has achieved this evolvability, it seems like it didn’t get erased by future evolution,” Zaman said.

This suggests that once evolution improves its ability to evolve, that trait does not disappear. Instead, it becomes a permanent feature, shaping how future generations adapt to their surroundings.

A new way of thinking about evolution

This study challenges the traditional view of evolution as a purely reactive process. Instead, it suggests that evolution can refine itself over time, becoming more efficient in adapting to changing environments.

If evolvability can evolve, it raises new questions about how life has persisted and diversified over billions of years. Organisms that develop a greater capacity for adaptation may have a long-term advantage over those that rely solely on immediate survival traits.

By demonstrating that evolution itself can evolve, this research opens new possibilities for understanding the complexity of life. It suggests that the ability to change and improve is not just a random occurrence but a fundamental aspect of how life progresses.

The study is published in the journal Proceedings of the National Academy of Sciences.

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