Adrian Bejan, the J.A. Jones Distinguished Professor of Mechanical Engineering at Duke University, was busy demonstrating the former for a class full of students when a thought struck him: this is not how nature operates. Evolution is a sequence of design changes happening on their own in a discernible direction; it never weds itself to a single point on a drawing board. An evolving system or animal is free to simply go with what works. Not so much that its performance suffers greatly, but enough that it opens access to other options near the so-called optimal design.

With science often looking to nature for clues to solve challenges, Bejan wondered if he might look the opposite way, to predict nature before looking at it. If problem solvers and builders were free to miss the absolute highest mark, how much greater might be the range of designs they consider plausible?

That’s the question that Bejan posits in a new paper published online May 16 in the journal Biosystems. Using two relatively simple examples — walkways ferrying passengers off a train and a bird flapping its wings — he discovers that the answer is, “quite a lot.”

“In engineering, design, theater, architecture or even the organization of this university, any form of design benefits from the ability to make good but imperfect decisions and the freedom to move on and contemplate other opportunities for improvement,” Bejan said. “If one is wedded to the idea of the absolute best, nothing new will ever be created.”

In the paper, Bejan first looks at the example of passengers arriving by train and walking across a room with many exit points. With the total area of the room remaining constant but the length and width of the room free to change, he solves for the optimal shape of the room to get all passengers where they’re going the quickest. With the solution equations in hand, he shows that providing even 1% wiggle room for imperfection away from the best performance opens the design space by 28%.

In his second example, Bejan looks at the flapping motion of birds at nearly constant altitude and speed. Considering the various forces involved — drag during gliding, lift created by wing size, speed and body size, among others — he formulates an equation for the rhythm of wings needed to maintain constant speed with minimum effort. While an optimal answer does exist, Bejan once again shows that allowing for just 1% imperfection above the theoretical minimum effort opens the design space by 20%.

Bejan says that he chose these examples because they involved changing only a single variable, a single degree of freedom — the shape for a room or the flapping rhythm for a wing. In more complex examples that involve many variables, these tiny tolerances for imperfection create an even wider range of “good enough” solutions.

The lesson learned is that science now has a predictive idea of how nature works. By focusing less on finding absolute optimal designs, researchers may use the freedom to iteratively move toward entirely new design concepts that wouldn’t otherwise have been within their sight. It also gives designs, methods and entire fields of study the ability to adapt to a changing world.

“The doctrine of chasing the best design is not helpful,” Bejan said. “The teaching of science should go hand-in-hand with the freedom to take a shot, hit the vicinity of the mark and move on. The end goal isn’t just to hit a bullseye, but to keep more arrows in your quiver to keep taking shots over a long period of time.”

This work was supported by a grant from CaptiveAire Systems.

The new species, Stelladens mysteriosus, comes from the Late Cretaceous of Morocco and was around twice the size of a dolphin.

It had a unique tooth arrangement with blade-like ridges running down the teeth, arranged in a star-shaped pattern, reminiscent of a cross-head screwdriver.

Most mosasaurs had two bladelike, serrated ridges on the front and back of the tooth to help cut prey, however Stelladens had anywhere from four to six of these blades running down the tooth.

“It’s a surprise,” said Dr Nick Longrich from the Milner Centre for Evolution at the University of Bath, who led the study. “It’s not like any mosasaur, or any reptile, even any vertebrate we’ve seen before.”

Dr Nathalie Bardet, a marine reptile specialist from the Museum of Natural History in Paris, said: “I’ve worked on the mosasaurs of Morocco for more than 20 years, and I’d never seen anything like this before — I was both perplexed and amazed!”

That several teeth were found with the same shape suggests their strange shape was not the result of a pathology or a mutation.

The unique teeth suggest a specialised feeding strategy, or a specialised diet, but it remains unclear just what Stelladens ate.

Dr Longrich said: “We have no idea what this animal was eating, because we don’t know of anything similar either alive today, or from the fossil record.

“It’s possible it found a unique way to feed, or maybe it was filling an ecological niche that simply doesn’t exist today. The teeth look like the tip of a Phillips-head screwdriver, or maybe a hex wrench.

“So what’s it eating? Phillips head screws? IKEA furniture? Who knows.”

The teeth were small, but stout and with wear on the tips, which seemed to rule out soft-bodied prey. The teeth weren’t strong enough to crush heavily armoured animals like clams or sea urchins, however.

“That might seem to suggest it’s eating something small, and lightly armoured — thin-shelled ammonites, crustaceans, or bony fish — but it’s hard to know,” said Longrich. “There were weird animals living in the Cretaceous- ammonites, belemnites, baculites — that no longer exist. It’s possible this mosasaur ate something, and occupied a niche, that simply doesn’t exist anymore, and that might explain why nothing like this is ever seen again.

“Evolution isn’t always predictable. Sometimes it goes off in a unique direction, and something evolves that’s never been seen before, and then it never evolves again.”

The mosasaurs lived alongside dinosaurs but weren’t dinosaurs. Instead, they were giant lizards, relatives of Komodo dragons, snakes, and iguanas, adapted for a life at sea.

Mosasaurs evolved around 100 million years ago, and diversified up to 66 million years ago, when a giant asteroid hit the Yucatan Peninsula in Mexico, plunging the world into darkness.

Although scientists have debated the role of environmental changes towards the end of the Cretaceous in the extinction, Stelladens, along with recent discoveries from of Morocco, suggests that mosasaurs were evolving rapidly up to the very end — they went out at their peak, rather than fading away.

The new study shows that even after years of work in the Cretaceous of Morocco, new species are continuing to be discovered. The reason may be that most species are rare.

The authors of the study predict that in a very diverse ecosystem, it may take decades to find all of the rare species.

“We’re not even close to finding everything in these beds,” said Longrich, “This is the third new species to appear, just this year. The amount of diversity at the end of the Cretaceous is just staggering.”

Nour-Eddine Jalil, a professor at the Natural History Museum and a researcher at Univers Cadi Ayyad in Morocco, said: “The fauna has produced an incredible number of surprises — mosasaurs with teeth arranged like a saw, a turtle with a snout in the form of snorkel, a multitude of vertebrates of various shapes and sizes, and now a mosasaur with star-shaped teeth.

“We would say the works of an artist with an overflowing imagination.

“Morocco’s sites offer an unparalleled picture of the amazing biodiversity just before the great crisis of the end of the Cretaceous.”

“It usually takes 10 to 20 years to discover a new material,” said Yanliang Zhang, associate professor of aerospace and mechanical engineering at the University of Notre Dame.

“I thought if we could shorten that time to less than a year — or even a few months — it would be a game changer for the discovery and manufacturing of new materials.”

Now Zhang has done just that, creating a novel 3D printing method that produces materials in ways that conventional manufacturing can’t match. The new process mixes multiple aerosolized nanomaterial inks in a single printing nozzle, varying the ink mixing ratio on the fly during the printing process. This method — called high-throughput combinatorial printing (HTCP) — controls both the printed materials’ 3D architectures and local compositions and produces materials with gradient compositions and properties at microscale spatial resolution.

His research was just published in Nature.

The aerosol-based HTCP is extremely versatile and applicable to a broad range of metals, semiconductors and dielectrics, as well as polymers and biomaterials. It generates combinational materials that function as “libraries,” each containing thousands of unique compositions.

Combining combinational materials printing and high-throughput characterization can significantly accelerate materials discovery, Zhang said. His team has already used this approach to identify a semiconductor material with superior thermoelectric properties, a promising discovery for energy harvesting and cooling applications.

In addition to speeding up discovery, HTCP produces functionally graded materials that gradually transition from stiff to soft. This makes them particularly useful in biomedical applications that need to bridge between soft body tissues and stiff wearable and implantable devices.

In the next phase of research, Zhang and the students in his Advanced Manufacturing and Energy Lab plan to apply machine learning and artificial intelligence-guided strategies to the data-rich nature of HTCP in order to accelerate the discovery and development of a broad range of materials.

“In the future, I hope to develop an autonomous and self-driving process for materials discovery and device manufacturing, so students in the lab can be free to focus on high-level thinking,” Zhang said.