The Atlantic, March 2, 2020

Link

On the morning of March 1, 1954, a hydrogen bomb went off in the middle of the Pacific Ocean. John Clark was only 20 miles away when he issued the order, huddled with his crew inside a windowless concrete blockhouse on Bikini Atoll. But seconds went by, and all was silent. He wondered if the bomb had failed. Eventually, he radioed a Navy ship monitoring the test explosion.

“It’s a good one,” they told him.

Continue reading “Nuclear Tests Marked Life on Earth With a Radioactive Spike” →

The New York Times, January 22, 2020

Link

In October 2015, scientists reconstructed the genome of a 4,500-year-old man who lived in Ethiopia. It was the first time that anyone had created a complete genetic snapshot of an African from an ancient skeleton.

Since then, other researchers have recovered DNA from skeletons unearthed in other regions of the continent. Now researchers have found the first genetic material from West Africa. On Wednesday a team reported that they had recovered DNA from four individuals in Cameroon, dating back as far as 8,000 years.

These ancient genomes contain vital clues to the history of the continent that have largely disappeared in the past few thousand years. Taken together, they are giving scientists a new vision of our species since it arose in Africa.

Continue reading “Ancient DNA from West Africa Adds to Picture of Humans’ Rise” →

The New York Times, January 15, 2020

Link

A bizarre tentacled microbe discovered on the floor of the Pacific Ocean may help explain the origins of complex life on this planet and solve one of the deepest mysteries in biology, scientists reported on Wednesday.

Two billion years ago, simple cells gave rise to far more complex cells. Biologists have struggled for decades to learn how it happened.

Scientists have long known that there must have been predecessors along the evolutionary road. But to judge from the fossil record, complex cells simply appeared out of nowhere.

Continue reading “This Strange Microbe May Mark One of Life’s Great Leaps” →

The New York Times, January 13, 2020

Link

The threat of air pollution grabs our attention when we see it — for example, the tendrils of smoke of Australian brush fires, now visible from space, or the poisonous soup of smog that descends on cities like New Delhi in the winter.

But polluted air also harms billions of people on a continuing basis. Outdoors, we breathe in toxins delivered by car traffic, coal-fired plants and oil refineries. Indoor fires for heat and cooking taint the air for billions of people in poor countries. Over a billion people add toxins to their lungs by smoking cigarettes — and more recently, by vaping.

Continue reading “Air Pollution, Evolution, and the Fate of Billions of Humans” →

The New York Times, December 20, 2019

Link

When European settlers arrived in North America, they were stunned to discover a gorgeous parrot.

The face of the Carolina parakeet was red; its head was yellow, its wings green. Measuring a foot or more from beak to tail, the parakeets thrived in noisy flocks from the Atlantic Coast to what is now Oklahoma.

“I have seen branches of trees as completely covered by them as they could possibly be,” John James Audubon wrote in 1830. When the parrots landed on a farmer’s field, “they present to the eye the same effect as if a brilliantly coloured carpet had been thrown over them.”

Continue reading “Once, America Had Its Own Parrot” →