Two years!

Two years ago today, Nothing in Biology Makes Sense! launched with a welcome from me and a post about coevolutionary medicine from CJ. Since then, we’ve written about everything from mammoth extinction events to diet fads, from the rationality of science denialism to the selective effects of agriculture—and we’ve had a lot of fun doing it.

So what’s ahead for this fine blog? Well, the National Network for Child Care “Ages and Stages” resource has this to say about two-year-old science blogs children:

Two-year-olds like to be independent! Favorite words are “Mine” and “No” and “I do it!” Emotions take on a roller coaster-like quality as 2-year-olds can go from excitement to anger to laughter within a few moments. A great deal of time is spent exploring, pushing, pulling, filling, dumping, and touching.

Here’s hoping our “terrible twos” are full of lots more exploring, and possibly also dumping. Also, we would like to apologize in advance if the Twitter feed gets a bit cranky when we run out of juice.

Is corn the new milk? Evolutionarily speaking, that is.

Cross-posted from Denim and Tweed.

ResearchBlogging.orgIt is a widespread misconception that, as we developed the technology to reshape our environment to our preferences, human beings neutralized the power of natural selection. Quite the opposite is true: some of the best-known examples of recent evolutionary change in humans are attributable to technology. People who colonized high-altitude environments were selected for tolerance of low-oxygen conditions in the high Himalayas and Andes; populations that have historically raised cattle for milk evolved the ability to digest milk sugars as adults.

A recent study of population genetics in Native American groups suggests that another example is ripening in the experimental fields just a few blocks away from my office at the University of Minnesota: Corn, or maize, may have exerted natural selection on the human populations that first cultivated it.

The target of this new study is an allele called 230Cys, a variant of a gene involved in transporting cholesterol. 230Cys is known only in Native American populations, and it’s associated with abnormally low production of HDL cholesterol (that’s the “good” kind of cholesterol) and thereby increased risk for obesity, diabetes, and heart disease. In Native American populations, the genetic code near 230Cys shows the reduced diversity associated with a selective sweep, which suggests that, although it’s not particuarly helpful now, this variant may have been favored by selection in the past.

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The evolution of music

This post is a guest contribution from James Gaines, who lives in Seattle, Washington and holds a Bachelors in Biology from the University of Puget Sound. James writes about natural history at The Glyptodon and is part of a fiction group at now we have to go to the hospital. He’s currently looking into science journalism graduate programs.

If you’d like to write a guest post for Nothing in Biology Makes Sense!, email Jeremy.

“Since music is the only language with the contradictory attributes of being at once intelligible and untranslatable, the musical creator is a being comparable to the gods, and music itself the supreme mystery of the science of man.” -Claude Levi-Strauss (1970)

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The Divje Babe bone is old, tens of thousands of years old, a shade less than a foot long and somewhat ugly. Its surface is mottled and rough. It is obviously the fragment of a larger piece – cracks run down its length and the ends have been snapped off. The incompleteness of the thing seems enhanced by two holes in the middle of the bone’s length. But these holes are different. They stare out like eyes, identical in size, perfectly centered, and perfectly artificial. It takes you a moment, but then you see.

It’s a flute – 42,000 years old.

Music is one of the few social constructs that truly permeates human culture, and reasons for this have fascinated scientists and philosophers for centuries. Even Darwin himself wrote on the subject, speculating about whether and how natural selection could explain it. Today, there seem to be three major ideas behind why music evolved. These are not the only ones, but are the most prevalent.

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Mass extinction: Did ancient humans get the party started 30,000 years ago?

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Bison priscus. The now-extinct Steppe Bison. This mummified individual, known as Blue Babe, was found in Fairbanks, AK, by a gold miner and is approximately 36,000 years old. Credit to Travis S.

During the last ice age, huge numbers of large mammals roamed the temperate zones of North America and Eurasia that lay south of vast continental glaciers. Familiar animals such as Woolly Mammoths, Woolly Rhinoceroses, Reindeer, Musk Oxen, Steppe Bison and the wild ancestors of domesticated horses along with more exotic creatures such as Glyptodon, a car-sized relative of armadillos and Megatherium, an enormous ground-dwelling sloth were abundant. With the ending of the ice age, which began around 21,000 years ago, many of these species experienced dramatic declines or went extinct. Woolly Rhinos, Mammoths, Glyptodon, and Megatherium went completely extinct, while Bison, Reindeer, Musk Oxen and wild Horse went through serious declines and range contractions.

These population declines roughly coincided with another major event in earth’s history, the global expansion of modern humans. Because of this synchronicity, there has long been debate about whether either is the cause. Did humans fuel their global expansion by hunting these animals to extinction, were they victims of a changing climate, or was it some combination of the two?

To answer this question, we need to know two main things. First, did climate change create extremely inhospitable environments for these species? Second, did the decline of these species coincide with contact with humans?

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