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Butterflies, Birds, Sea Turtles, and Whales — News from the Design of Life

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Research on the stars of the Design of Life films continues to reveal marvels beyond the reach of unguided processes.

Butterflies

Metamorphosis, one of the Design of Life films from our friends at Illustra, shows butterflies finding their host plants with extreme precision, utilizing multiple sensory modalities to ensure that the eggs would be laid on the right food source for the caterpillars. Now, researchers have added leaf shape to the list of cues, Phys.org says. Observations of the red passionflower butterfly show that females have an innate preference for plants with a particular leaf shape. But they can learn to overcome their preference for other shapes that may be more abundant in the rainforest, or for ones with a better food reward.

This shows that flexibility is a design feature, keeping an organism from getting into a rut that might lead to extinction. It also promotes biodiversity in the ecosystem, we learn. So in addition to odor, touch, and taste, the tiny flyers can also use vision. That makes sense because they’re well equipped for that as well. As Ronald Boender remarks in Metamorphosis, butterflies have better eyesight than humans.

Birds

Penguins don’t feature in Flight: The Genius of Birds, but they deserve more-than-honorable mention. Recently, scientists outfitted some of New Zealand’s rockhopper penguins with geolocators to see where they go, as Carsten Egevang’s team did for Arctic terns in the film. Rockhoppers spend up to six months at sea during the winter, but their paths were previously unknown. BBC News says that researchers were “astonished by the birds’ long-distance journeys.” The relatively small penguins travelled up to 15,000 kilometers (9,320 miles) — and that was by swimming! Adding to the feat is the birds’ vertical distance when they dive to catch fish, which as not measured by the devices, “so the actual effort is even greater.”

Scientists are beginning to combine data from geolocators with next-generation gene sequencing to learn more about bird migration. Scientists at the University of British Columbia installed geolocators on migrating songbirds called Swainson’s thrushes. Two related populations take very different routes from Canada, one down the Pacific coast to Central America, the other down the east coast to South America. The researchers found a genetic basis for the difference:

By linking the migratory behavior of hybrids to their genetic makeup, these researchers pinpointed a single cluster of roughly 60 genes on one chromosome that largely accounts for the difference in migration patterns.

The genes play an important role in the birds’ circadian, nervous and cell signalling systems. They are also located in regions of the genome that have reduced movement of genes from one population of thrushes to the other.

“Smaller scale studies have associated some genes in this region with migratory behavior in organisms as diverse as butterflies, fish and other birds,” said UBC zoologist Darren Irwin, senior author of the study. “These results provide even stronger evidence that evolution of this genetic cluster can cause different migratory routes, facilitating the evolution of two species from one.” [Emphasis added.]

The speciation angle can’t be pushed too far, since they are all Swainson’s thrushes and are capable of interbreeding or hybridizing. Also, the study may not have taken epigenetic modifications into account. Nevertheless, it is interesting to find genetic variability reflected in the behavioral differences, again showing that flexibility can help a species remain viable under changing conditions.

Soaring birds manage to achieve great heights with a minimum effort. A study published in the Proceedings of the National Academy of Sciences reveals more of their techniques. The birds know how to turn challenges to their advantage. Researchers from UC San Diego say in the paper,

Thermals are ascending currents that typically extend from the ground up to the base of the clouds. Birds and gliders piggyback thermals to fly with a reduced expenditure of energy, for example, during migration, and to extend their flying range. Flow in the thermals is highly turbulent, which poses the challenge of the orientation in strongly fluctuating environments. We combine numerical simulations of atmospheric flow with reinforcement learning methods to identify strategies of navigation that can cope with and even exploit turbulent fluctuations.

That’s a design strategy that drone makers might learn from, notes Phys.org.

Sea Turtles

Illustra’s film Living Waters mercifully avoided shots of hatchling sea turtles getting picked off by crabs and birds, though it mentioned that hazard. News from the University of Bristol reveals one way green turtles avoid capture: they hatch en masse at the same time. This swamps the predators, allowing more of them to reach the safety of the water. They also emerge at night when they are less likely to be seen. Since they emerge from under the sand, they must rely on biological clocks, not sunlight, to know when to hatch. They also arrive on the surface with an uncanny sense of direction to the water, and travel fast with little flippers well designed to negotiate both sand and sea.

Unfortunately, birds and crabs are not the only dangers sea turtles face. National Geographic has an alarming story about a Vietnamese trafficker caught with a huge haul of endangered Hawksbill sea turtles, seven thousand in all. An investigator “never thought it would be this bad” when he entered three secret warehouses reeking of death. The illegal trader has not yet been arrested. Stephen Dunbar, who appears in the film, works to rescue sea turtles in Honduras and educate others about them.

Whales

In his new book Undeniable, Douglas Axe tells about his fascination watching orcas off the coast of Washington using teamwork at the hunt. Their show-off skill hoisting their heavy bodies into the air also elicited his admiration. He uses that experience to argue his point that orcas, salmon, and other creatures represent complete “wholes” as organisms that do not need to evolve into something other than what they are.

Living Waters includes beautiful drone shots of dolphins and humpback whales taken by Captain Dave Anderson, interviewed in the film, who was a pioneer in this photographic technique. The Associated Press reports that drone technology is being used more and more by whale researchers “looking for clues to sustain healthy populations of the marine mammals.” Observations that would be difficult from a ship can be made with drones, such as estimating the sizes of pods or orcas and false killer whales.

The vantage point of the drone also allowed them to more accurately count the number of individuals in a pod, including mothers and calves that sometimes stay underwater. The number of calves helps researchers gauge the whale’s reproductive health. The perspective also allows the scientists to get more accurate size estimates for individual whales.

Whales and dolphins play a crucial role in the ecosystem around the Hawaiian archipelago, where NOAA researchers tried out their drones. “If populations decrease,” reporter Caleb Jones remarks, “…the oceans food chain becomes unbalanced and could impact the entire ecosystem.”

The Illustra film describes the elaborate echolocation system used by dolphins. And don’t forget the songs of the Humpback whale. Phys.org has a new question: “What do sperm whales say?” Actually, nobody knows. A team listened in on a pod of seven of these giants swimming near the Azores Islands. “They clearly have something on their minds — but to be perfectly honest, we haven’t the faintest idea what that might be.”

Initial indications are that the whales communicate in clicks analogous to Morse Code.

Much like Morse code, these messages consist of a series of tapping (also described as clicking) sounds in a variety of combinations, such as four long taps followed by two short ones. The scientists registered 21 different messages.

An audio clip in the article lets you listen in on some of the sounds recorded by the scientists.

“One could imagine that the vocalisations give information about who each of the individuals in the group are, whether they are heading for the surface or depths or if they have found food. It could be mothers calling to their young or females inviting males to mate with them.”

These are just guesses at this point. One 9.3-meter whale was the most talkative in the pod. Four others vocalized, but two remained quiet. Research goes on. Here’s more from the article about “the incredible world of sperm whales”:

Like elephants, sperm whales live in matriarchal groups. When young males reach maturity, they leave the group and travel north to the waters around Iceland and northern Norway, where they remain until they have doubled in size. Once they have grown sufficiently, they make their way back to the tropics to find a female to mate with.

Sperm whales are capable of making the loudest sounds of any animal on the planet. They use these sounds for echolocation and as a form of communication.

The sperm whale is the world’s largest predator, and it can track squids up to a kilometre away using echolocation.

As these news items show, evidence for the Design of Life is abundant and growing. It’s clear that much of good science works to understand the design that is Undeniable to all who consider it with an open mind.

Photo: Thrush with geolocator, via University of British Columbia.

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