The evolution of penguins from their flying seabird ancestors into the flightless denizens of marine environments from frigid Antarctica to the tropical Galapagos Islands is among the wonders of the animal kingdom.
Researchers on Tuesday offered the most thorough examination to date of the history of penguins dating back to their origins more than 60 million years ago, including identifying a suite of genes crucial in adaptations related to underwater vision, long dives, body temperature regulation, diet and body size.
The researchers sequenced the genomes of the 20 living penguin species and subspecies. With more than three quarters of known penguin species now extinct, the researchers also included in their analysis 50 fossil species using skeletal data.
Photo: Reuters
The researchers said penguins evolved from a common ancestor shared with a group of seabirds that includes albatrosses and petrels. Penguins first evolved the ability to dive, like a puffin, and subsequently lost the ability to fly as they adapted to an aquatic realm, becoming excellent swimmers and divers.
The earliest-known penguin — dating back to 61 million years ago, about 5 million years after the mass extinction event that doomed the dinosaurs — is called Waimanu manneringi, from New Zealand.
“To me, penguins are a perfect example of a major evolutionary transition, like the evolution of an aquatic lifestyle in whales or flight in bats,” said avian paleontologist Daniel Ksepka of the Bruce Museum in Greenwich, Connecticut, co-author of the study published in the journal Nature Communications.
Photo: Reuters
“We know penguins evolved from flying birds, but that happened over 60 million years ago and we need to look to the fossil record to piece together where, when and how that happened. Plus, penguins are ridiculously charming creatures. They love, they fight, they steal, and because of their funny upright posture it’s really easy to imagine them having all the same motivations as people,” Ksepka said.
The study illustrated how global temperature changes — oscillations between cold and warm periods — and shifts in major ocean currents have been important drivers of penguin evolution.
“We estimated how populations of each penguin species fluctuated over the last 250,000 years from signatures left in their genome by population crashes and booms,” Ksepka said. “The waxing and waning of ice sheets had a big impact on penguins, and species vulnerable to receding sea ice may suffer greatly from future global heating.”
Photo: Reuters
Penguins also were found to exhibit the lowest evolutionary rates yet detected among birds.
Penguins live primarily in the Southern Hemisphere, including species like the Adelie penguin along Antarctica’s coastlines. The Galapagos penguin is the only one found north of the equator.
University of Copenhagen postdoctoral researcher and study lead author Theresa Cole said the research uncovered a variety of genes likely involved in unique penguin physiological adaptations.
They show gene mutations that shift their vision toward the blue end of the color spectrum. Blue light penetrates more deeply into the ocean than light at the red end of the spectrum, so this trait helped fine-tune vision for low-light, underwater acuity.
Genes that help birds detect salty and sour tastes are active in penguins. But genes that help detect bitter, sweet and savory tastes are inactivated. Those may no longer be needed as penguins forage in cold, salty water and typically swallow prey including fish, shrimp and squid whole.
Penguins exhibit a flattening and stiffening of their wing bones and a reduction of their flight feathers into tiny structures that help convert wings into flippers. They also reduced the air spaces in the skeleton and increased bone wall thickness to increase diving efficiency, as well as adding the ability to store more oxygen in their muscles for long dives.
Penguins were once much larger than today’s species. One species, Kumimanu biceae, that inhabited New Zealand between 55 and 60 million years ago stood about 6 feet (1.8 meters) tall. The largest extant species, the emperor penguin, is about 3 feet (1 meter) tall.
For many people, Bilingual Nation 2030 begins and ends in the classroom. Since the policy was launched in 2018, the debate has centered on students, teachers and the pressure placed on schools. Yet the policy was never solely about English education. The government’s official plan also calls for bilingualization in Taiwan’s government services, laws and regulations, and living environment. The goal is to make Taiwan more inclusive and accessible to international enterprises and talent and better prepared for global economic and trade conditions. After eight years, that grand vision is due for a pulse check. RULES THAT CAN BE READ For Harper Chen (陳虹宇), an adviser
Traditionally, indigenous people in Taiwan’s mountains practice swidden cultivation, or “slash and burn” agriculture, a practice common in human history. According to a 2016 research article in the International Journal of Environmental Sustainability, among the Atayal people, this began with a search for suitable forested slopeland. The trees are burnt for fertilizer and the land cleared of stones. The stones and wood are then piled up to make fences, while both dead and standing trees are retained on the plot. The fences are used to grow climbing crops like squash and beans. The plot itself supports farming for three years.
The breakwater stretches out to sea from the sprawling Kaohsiung port in southern Taiwan. Normally, it’s crowded with massive tankers ferrying liquefied natural gas from Qatar to be stored in the bulbous white tanks that dot the shoreline. These are not normal times, though, and not a single shipment from Qatar has docked at the Yongan terminal since early March after the Strait of Hormuz was shuttered. The suspension has provided a realistic preview of a potential Chinese blockade, a move that would throttle an economy anchored by the world’s most advanced and power-hungry semiconductor industry. It is a stark reminder of
May 4 to May 10 It was once said that if you hadn’t performed at the Sapphire Grand Cabaret (藍寶石大歌廳), you couldn’t truly be considered a star. Taking the stage at the legendary Kaohsiung club was more than just a concert. Performers were expected to entertain in every sense, wearing outlandish or revealing costumes and staying quick on their feet as sharp-tongued, over-the-top hosts asked questions and delivered jokes that would be seen as vulgar, even offensive, by today’s standards. Opening in May 1967 during a period of strict political and social control, Sapphire offered a rare outlet for audiences in
RSS