In this extraordinary adaptation strategy, Thailand’s Moken sea gypsies can see twice as clearly underwater by controlling the size of their pupils. What was generally considered an automatic reflex for the rest of us is now thought to be something that any child under 5 could learn how to do.
From a study called Superior Underwater Vision in a Human Population of Sea Gypsies by Dr. Anna Gislén:
The Moken may learn to do this due to their extensive use of their eyes in water, where accommodation and concurrent pupil constriction is necessary for them to see the items they gather for food. It should then be possible for all humans to learn to see better underwater. But because sea gypsies have lived by and off the sea for thousands of years, evolution may also have favored those who had intrinsically better underwater accommodative powers. The ability to see well underwater could have become a genetic trait. Another possible explanation is that accommodation underwater is a side effect of the diving response; the parasympathetic nerves that control this reflex also control pupil constriction.
Read more at National Geographic.
In the archives: more swimming and these extreme eye closeups.
In Onward: Searching for Life in Iceland’s Frigid Fissures, National Geographic grantee and biology researcher Jónína Ólafsdóttir goes diving in search of tiny arthropods in the underwater volcanic fissures of Iceland’s Thingvellir National Park. She is joined by NatGeo multimedia journalists Spencer Millsap and Dan Stone.
“When I started doing this research, I was amazed that no one had ever done it before,” she said one morning earlier this week as we drove to her favorite dive site. Iceland has a lot of research questions related to biology and geology that have never been answered, let alone even asked. “Iceland is a really great place for a scientist with an explorer’s heart,” she says…
Ecologists are often asked why they might study one particular animal, especially a small one that has little impact on humans. Jónína’s answer goes like this: humanity might never be dependent on microscopic arthropods but understanding how animals work together, how they depend on each other holds lots more clues about an area’s environmental history—and its future. At the top of the world, seeing how species change and adapt may indicate what happens as the climate changes around the world.
Read more about Ólafsdóttir's research at National Geographic, and check out more scuba diving videos in the archives.
Via skeptv, New Scientist reports on this time lapse video of snail development from embryo to hatching:
Oliver Tills of Plymouth University, UK, and colleagues tracked the timing of 12 different events – including the formation of the eyes and the shell – over the two weeks it takes embryos of the pond snail Radix balthica to develop. They then compared these figures with those obtained from the snail’s parent (R. balthica is hermaphroditic so can have just a single parent).
There are more videos with cells in the archives.