Levi Morran, a graduate student at the University of Oregon, had the pleasure of watching 50 generations of roundworms procreate and concluded that, as problematic as males are, sex with a mate is better than sex alone.
(Credit: University of Oregon)Sex with oneself in the world of plants and animals is called, fittingly, "selfing." The offspring of selfing females share 100 percent of their mothers' genes, and they can go on to produce their own offspring.
The offspring of "outcrossing" (the sexy science term for mating) males and females, on the other hand, share 50 percent of each parent's genes. Some offspring, naturally, are males that cannot bear offspring.
Of the two systems, it turns out that outcrossing produces offspring whose more diverse genetic codes lead to greater chances for longer lives, lower susceptibility to genetic mutations, and better adaptability to changing environments, according to more than 100 mini-evolution experiments with nematode worms at the University of Oregon. Researchers are reporting their findings, among creatures that can reproduce via both selfing and outcrossing, online on Wednesday in advance of regular publication in the journal Nature.
While selfing females don't have to put up with "pesky males" to reproduce, a problem known as the evolutionary "cost" of males, and they can, in fact, populate twice as quickly when going it alone, the genetic benefits of outcrossing explain why the phenomenon exists at all, the researchers explained.
"Biologists going all the way back to Charles Darwin have been puzzled why sexual reproduction via outcrossing exists at all," said UO biology professor Patrick C. Phillips, who turned to two of his students in the UO Center for Ecology and Evolutionary Biology to help determine what good could possibly come of worms having partners.
Levi Morran and Michelle Parmenter conducted more than 100 mini evolutions for 50 generations, in which 60 populations of nematodes, also known as roundworms, were adapted to new environments, including to the presence of a bacterial pathogen that eats worms from the inside out, according to a statement.
Morran and Parmenter genetically engineered the worms, which normally practice a combination of both selfing and outcrossing, to reproduce just one or the other. Strictly selfing populations, they found, were far more susceptible to accumulating harmful mutations and unable to adapt to rapidly changing environments.
"The inability of selfing populations to adapt to changing environmental conditions helps to explain the observation that selfing populations are much more likely to go extinct than outcrossing populations," says Morran, a graduate student and lead author of the study.
While males are clearly problematic for several reasons, their evolutionarily benefits do outweigh their costs, Phillips concludes. Sound familiar, ladies?
Both the American public and researchers have a high regard for scientific advancement. But they disagree over the standing of science in the U.S.
A full 84 percent of the public believes science's effect on society has been mostly positive, reveals a survey released Thursday by the Pew Research Center. And 70 percent feel scientists contribute a lot to society's well-being.
However, only 17 percent of the public think that U.S. scientific achievements rank as best in the world. That contrasts with 49 percent of scientists surveyed who feel U.S. science is still at the top compared with other countries.
Among the public, America's scientific prowess has declined over the past 10 years. In the current survey, only 27 percent of Americans cited scientific advancement as one of the country's most important achievements, compared with 47 percent in May 1999.
(Credit:
Pew Research Center)
Scientists also have their own concerns. Among those surveyed, 85 percent see the public's lack of scientific knowledge as a major problem. Almost half criticize the public for having unrealistic expectations about scientific progress.
The media also shares in the blame, say scientists. About 48 percent of scientists say the news oversimplifies science. Newspaper coverage comes off best, with 36 percent of scientists rating it excellent or good. But TV coverage of science fares worse--only 15 percent of scientists see it as excellent or good.
(Credit:
Pew Research Center)
The survey uncovered other differences in opinion between scientists and the public.
The majority of scientists firmly believe in evolution, with 87 percent saying humans and other living creatures have evolved over time through processes such as natural selection. Only 32 percent of the public believes the same.
A full 84 percent of scientists say global warming is the result of human actions, such as burning fossil fuel, while only 49 percent of the public agrees.
As part of the survey, the public was also quizzed on its knowledge of science, with mixed results. Fully 91 percent of those tested know that aspirin is used to prevent heart attacks. Around 82 percent said that GPS technology relies on satellites. But only 47 percent knew that lasers do not work by using sound waves, and a mere 46 percent remembered that electrons are smaller than atoms.
(Credit:
Pew Research Center)
Pew's survey (PDF) of the general public targeted 2,001 adults by phone from April to June. The survey of scientists was conducted online in collaboration with the American Association for the Advancement of Science (AAAS) and reached 2,533 members of the AAAS from May to June.
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