Entries in evolution (2)


Scientists Hint at Why Laughter Feels So Good

BananaStock/Thinkstock(OXFORD) -- Laughter has long been suspected as a source of health and well-being, but it has been hard to actually definitively pinpoint why this is.

According to The New York Times, Robin Dunbar, an evolutionary psychologist at Oxford, argues that it is the physical act of laughing that explains why it feels so good. He says that it is the muscular exertions that are involved in producing laughter that triggers an increase in endorphins.

His findings also fit in well with the idea that laughter contributes to group bonding and the evolution of highly social humans. Dr. Dunbar describes social laughter, as relaxed and contagious as it is, as “grooming at a distance.”

As part of his research, in five sets of students in the laboratory and one field study at comedy performances, Dr. Dunbar and his colleagues tested resistance to pain both before and after social laughter.

The findings, published in the Proceedings of the Royal Society B: Biological Sciences, eliminated any inclination that the pain resistance measured was the results of a sense of well-being, rather than the actual laughter.  

When analyzed, these results showed that laughing did increase pain resistance, whereas mere good feeling in a group setting did not.

Dr. Dunbar also concluded that endorphin activation comes from laughter, rather than the other way around.  He also believes that laughter was favored by evolution because it helped to bring groups together, just as physical activities such as dancing and singing.

Copyright 2011 ABC News Radio


Scientists Capture Evolution in the Lab

Comstock/Thinkstock(GAINESVILLE, Fla.) -- Scientists say they have caught "evolution in the act" in a series of experiments that open a new window into understanding how new species gradually morph into plants and animals that are distinctly different from their parents.

The experiments, conducted at the University of Florida in Gainesville, surprised the scientists by demonstrating that the development of a new species doesn't occur instantly, but instead is the product of succeeding generations that are able to alter their genetic blueprint as they gradually mature into a stable plant or animal.

The star of the show is a humble member of the daisy family, Tragopogon miscellus, better known as "goatsbeard," which began its long journey toward stability about 80 years -- and 40 generations -- ago.

"We can see for the first time what happens when a new species is formed," biologist Doug Soltis of the University of Florida said in a telephone interview. "We can see the process unfold, and it's still ongoing even as we speak. They (the plants) haven't figured all this out yet."

The research, published in the journal Current Biology, offers some startling insights. The new species first appeared in the Pacific Northwest sometime after 1920 when its parents produced a hybridized offspring with double the number of chromosomes. But unlike its parents, the genes were not rigidly programmed to perform certain functions. Instead, for many generations the genes acted sort of like free agents.

"Different genes are expressed at different times and in different places," Soltis said. So the new species had much greater diversity than would have been expected, creating a genetic blueprint as it went along, from one generation to the next, turning some genes on, and others off, and eliminating some entirely.

That, of course, gave goatsbeard an enormous advantage in adapting to new environmental challenges or opportunities.

"This is evolution at work," Soltis said. "You can see the fine tuning begin to take place."

Copyright 2011 ABC News Radio

ABC News Radio