Skin Wrinkles in Water for Grip

Summary:
     After a long time in water, vessels in our palms and fingers contract, which creates temporary wrinkles in the skin there. For a long time, it was commonly thought that the skin on the fingertips absorbed water and increased in size, creating the wrinkles. However; this was also doubted because of the fact that people with nerve damage didn't exhibit this trait. After careful observations, it was deemed that the blood vessels contracted, and the skin stayed the same size.
     A biologist named Tom Smulders recently concluded that this was an adaptation that helps humans handle objects when they are wet. He experimented by having 20 people who started out with dry hands move a total of 45 submerged objects (45 for each person) to another container. He then repeated the same test, but instead having the test subjects soak their hands in water for 30 minutes prior to the test. Both tests were timed.
     In his results, he found that on average, people took 15 seconds longer to pick up submerged objects when their hands were unwrinkled, compared to when they had wrinkles in the skin of their hands. Mr. Smulders speculates that this adaptation came into play to help humans with things such as keeping their footing in water, or holding on to wet tools during the rain, fishing, or even uprooting sea plants to eat.

Relevance:
     In Unit 7, we learn about evolution, natural selection, and adaptations. Wrinkling skin is an adaptation, because it helped hominids grip wet objects such as food and tools, which in turn affected their ability to survive. Because it affected their ability to survive to reproduction, it is related to natural selection, adaptations, and (biological) fitness.


Link to Article: http://www.guardian.co.uk/science/2013/jan/09/skin-wrinkle-water-grip