Earth's Greatest Migration

Earth's Greatest Migration

One night in the mid-1800s, a naturalist in a boat saw something mysterious. The surface water was teeming with daphnia, zooplankton more commonly known as ‘sea fleas.’ The next morning, they had disappeared. The next night, they were there again. Where did they come from? Where did they go? For a century, this was a mystery. Then navy ships, using sonar to track submarines, found that the deep ocean bottom appeared far shallower at night – when it was moving upward! They theorized they were getting a false reading, as the sonar bounced off swarms of sea creatures, rising in the water column. Scientists took a trawler out at night and brought up nets full of small fish, crustaceans and jellyfish. The navy operators were right. They had discovered the DVM, the Diel Vertical Migration. Further investigation revealed what was happening. Phytoplankton – tiny floating algae – stay near the surface during the day to collect sunlight for photosynthesis. Small creatures that eat phytoplankton hide in deep water during the day, to avoid being eaten themselves. Then at night, they migrate to the warmer surface to feed and mate. Large predators, even sharks and whales, follow them up. As dawn approaches, they all sink back into the deep. It turns out this happens in every ocean, in every lake, everywhere on the planet. It’s the largest migration on Earth – and amazingly, it happens every night.

Real-Life Hobbits

On the island of Flores, in Indonesia, a team of anthropologists made a discovery so surprising, they kept it a secret for a year. In a cave called Liang Bua, they had uncovered 100 skeletal fragments of about 14 individuals – so small, that at first, they thought they might be the remains of children. But more investigation showed wisdom teeth and wear on bones that definitively marked these skeletons as adults – and a newly discovered species of hominin, just over 3 feet tall. They called them Homo floresiensis, after the island. But they nicknamed them hobbits, and the moniker stuck. This community of hobbits had lived on Flores from about 100,000 years ago until just 50,000 years ago, then went extinct. More recent discoveries on the island found the hobbits’ even smaller ancestors, who arrived between 1 million and 700,000 years ago, and quickly shrank in size, in a process called island dwarfism, where species get smaller in response to limited resources. Indonesia also once had dwarf elephants and other creatures. But the presence of the hobbits, at a time when Homo sapiens were already well established in Africa, Europe and the Middle East, and venturing into Australasia, shocked the anthropology world. And reminded us that, for hundreds of thousands of years, there were several kinds of successful humans on Earth -- before our kind became the sole survivor.

Gold From Earthquakes

Gold has been valued by humans for at least 7,000 years. The earliest gold items were found in Bulgaria, from the 5th millennium BC. The first mines were likely in the ancient African kingdom of Nubia. Egyptians created great wealth, and great art, from gold. Gold is valuable because it’s so unusual. It’s very dense, even denser than lead. It’s very durable, yet also very soft. It’s the most malleable metal – we can roll it into sheets thin enough to transmit light. And it’s an excellent conductor of both heat and electricity. Gold miners noticed 2 other curious properties. Most gold is found in quartz. And it’s often found in earthquake zones. Scientists wondered, could the two be connected? So, they set up an experiment to find out. They immersed quartz crystals in a solution of water and gold ions. Then they subjected the tank to 20 hertz soundwaves, simulating an earthquake. The sound pressure triggered the piezoelectric properties of quartz – when subjected to physical stress it produces an electrical current. The electric charge drew the gold out of the water solution to clump on the quartz. That gold carried the current, because it’s such an excellent conductor, and drew more gold to clump onto it. This may explain why the largest gold nuggets are found on quartz. And, if we could attract it to an electric current, it just might be a new way to prospect for gold.

World's Deadliest Animal

What’s the world’s most dangerous animal? Sharks? Nope, they bite only 70 people a year, with just six fatalities. Poisonous snakes? They kill about 50,000. But far and away the most dangerous is the mosquito. It kills a million people a year, and sickens 250 million more! But we may be able to stop it, with an even tinier creature. There are 3,000 species of mosquito. Different ones can carry malaria, West Nile virus, Zika, yellow fever, dengue, Japanese encephalitis, and more. They don’t cause these diseases, but instead bite an infected person, then pass it to others. Some of these diseases, like malaria, have medicines to prevent and treat them. Others like dengue, don’t. But scientists may have found a novel solution – infecting the mosquitoes themselves, with bacteria called Wolbachia. Wolbachia exist symbiotically in about 50% of insect species. When introduced to mosquito populations, they consume essential molecules within the insect, like cholesterol -- the same thing that Zika and dengue rely on. This means those diseases can’t survive within the mosquito and can’t be transferred to more humans. Wolbachia don’t kill the mosquitoes, and are found to be harmless to humans and other creatures that depend on mosquitoes for food, like birds and bats. A microbiological treatment for a global disease problem.

Fibonacci Sequence

Amazingly, the structure of most living things, and many other things as well, conforms to one sequence of numbers. It was described in the 1200s by Italian mathematician Leonardo Pisano, also called Fibonacci, working from earlier Indian ideas. The Fibonacci Sequence is 1, 1, 2, 3, 5, 8, 13 and onward – where the first two numbers, one and one, add up the next number, two. The next two numbers, one and two, add up to the next number, three. And so on. Most flowers have three, five, eight or thirteen petals. Spirals found in nature – seeds in a flowerhead, snail shells, even hurricane clouds – expand outward according to the sequence. Scientists looked at 12,000 spirals in different species and found that 90% adhered to the Fibonacci Sequence. But we’re not sure why. The pattern must confer some kind of structural advantage, enough that it continues to persist in newly formed species. Human designers often use the Fibonacci Sequence intentionally when designing art or architecture. Or unintentionally, by mimicking the geometries of nature. You can see it the next time you pick up a pinecone, eat an artichoke, or look in the mirror. The human body has one head, one torso, two arms, with three segments each, ending in five fingers. Efficient and elegant, the Fibonacci Sequence is the shape of nature.