Understanding the evolution of nocturnal mammals by studying their extinct relatives

Humans are diurnal. We sleep at night and are active during the day. (That isn’t to say that I feel particularly diurnal most mornings, given that my alarm has to make it through a few snooze cycles to wake me up and coffee is the only thing keeping me from napping under my desk at work.) Most mammals, though, don’t share our ostensible predilection for daylight; only 20% of mammal species are diurnal like us. Of our mammalian relatives, nearly 70% are nocturnal. The rest are crepuscular (active at dawn and dusk) or cathemeral (active during both day and night).

A tarsier (Flickr: )

A tarsier from Borneo. (Flickr: Erwin Bolwidt)

Mammalogists like myself often think nocturnality is a particularly mammalian thing because—let’s be honest here—nearly all of the coolest nocturnal vertebrates are mammals. How can you compete with the likes of tarsiers, vampire bats, leopards, and—strangest of them all—the aye-aye? I’ll throw the ornithologists a bone and acknowledge the enduring awesomeness of owls, but they are the odd birds out in a group that’s mostly diurnal.

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Science and Religion Blah Blah Blah

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A perennial question, a constant product of the click-bait-and-outrage factory known as internet, that has been, and perhaps forever will be posed, answered, yelled about, and generally used to beat the life and enthusiasm out of so many reasonably evolutionary biologists is “CAN RELIGION AND SCIENCE (PARTICULARLY EVOLUTIONARY BIOLOGY FOR SOME REASON) COEXIST??!?!!?!!?”

The answer is a simple no, and yes. That’s it. No, because religious belief systems often tend to include specific factual claims about the material world that turn out to be total nonsense. For example, the earth and everything on it was not created in 7 literal days. Therefore, one cannot hold both this belief and the belief that scientific inquiry was a fantastic way of generating useful, more-or-less objective knowledge about the world, because actual scientific evidence absolutely refutes such a notion.

On the other hand, yes, because arguably the most important elements of religious belief systems involve claims about immaterial things, such as the existence and nature of the human soul. On these topics, science literally has nothing to say. One cannot measure with calipers, a telescope, a mass spec, an Illumina Hi-Seq or any other tool devisable by humanity, a divine presence purported to pervade all existence. The hypothesis that a God of any sort exists can be rescued from any and every contradictory empirical finding.

Perhaps you can tell, but I’ve written this rant because I’m sick and tired of the web-traffic generating mutualism that exists between religious fundamentalists and atheists claiming to champion science. They both make equally absurd and unsupported claims about religion and science. Their statements are always absolute.

This was supposed to be a link post, so if you’d like to see the New York Times opinion piece that got me all in a rage about this, here it is. But I don’t recommend reading it.

Postscript: I am in no way religious. I also recognize that certain specific religious beliefs are both widely held, harmful, and in direct contradiction to established scientific facts. I think these beliefs ought to be combated. This does not in any way change my overall tolerance of religious belief.

Thanks, Bush and Obama!

President Obama is expanding the Pacific Remote Islands Marine National Monument today from the wonderful 86,888 square miles President George W. Bush set up in 2009, to about 490,000 square miles. I gotta love anything involving ocean conservation. Thanks, Bush and Obama!

“This is a great moment,” said Greg Stone, chief scientist for Conservation International. “This is some of the last real tropical ocean wilderness left on the planet, so it’s good put some of these kind of reef systems aside. On top of that there are the protections for the open ocean and I’m assuming for the sea floor from mining,” he said.

From the Guardian article: “Tarawa atoll. Photograph: Richard Vogel/AP”

The evolution of human facial diversity

Signalling individual identity is critical in many aspects of human social interaction (click for video!).

We all rely on our ability to recognize other people’s faces to get along in the world. Most people don’t think too hard about this, it’s so fundamental to our existence. But it turns out that in order to stand out in the crowd, you need to be, well different. A recent study shows that human faces are in fact, much more different from one another than other traits, and suggests that this high facial diversity has evolved specifically to signal individual identity. It’s a pretty interesting story, and I look forward to digging into the details.

Check out this NatGeo piece on the work, and the original publication (paywalled).

Literature Cited:
Sheehan, Michael J., and Michael W. Nachman. “Morphological and population genomic evidence that human faces have evolved to signal individual identity.” Nature Communications 5 (2014).

Best. Broader impact. Ever.

Like everyone with an Internet connection, earlier this month I heard a fair bit about U.S. 7th Circuit Court Judge Richard Posner’s ruling striking down bans on same-sex marriage in Indiana and Wisconsin. As Mark Joseph Stern put it at Slate, “Posner … sounds like a man who has listened to all the arguments against gay marriage, analyzed them cautiously and thoroughly, and found himself absolutely disgusted by their sophistry and rank bigotry.” Here’s a choice sample from the full opinion:

The challenged laws discriminate against a minority defined by an immutable characteristic, and the only rationale that the states put forth with any conviction—that same-sex couples and their children don’t need marriage because same-sex couples can’t produce children, intended or unintended—is so full of holes that it cannot be taken seriously.

What I hadn’t heard before is that Posner’s opinion also includes a short run-down on research about the biological basis of sexual orientation, and it has more than one familiar citation:

Although it seems paradoxical to suggest that homosexuality could have a genetic origin, given that homosexual sex is non-procreative, homosexuality may, like menopause, by reducing procreation by some members of society free them to provide child-caring assistance to their procreative relatives… There are other genetic theories of such attraction as well. See, e.g., Nathan W. Bailey and Marlene Zuk, “Same-Sex Sexual Behavior and Evolution,” forthcoming in Trends in Ecology and Evolution

That’s actually a reference to a 2009 review, which is online in PDF format—it covers the diversity of same-sex sexual behaviors across the animal kingdom. It hardly mentions Homo sapiens, but it is one of the sources I give to people who want a solid introduction to current scientific thinking about how same-sex attraction could have evolved. If you ask me, one could do a lot worse than having a paper cited in a groundbreaking legal ruling. And it’s a reminder to those of us studying the history of life in general that our work can have unexpected consequences beyond the lab.

Tigers and Birds

Many, many world-class ornithologists have called or do call the Louisiana State University Museum of Natural Science home. This year, LSU grad students Mike Harvey (a NiB! contributor!) and Glenn Seeholzer along with LSU alum Dan Lane and Peruvian ornithologist Fernando Angulo are going to Peru this October to find the most bird species they can in a single 24 hour period and they’re hoping to break the world “Big Day” record. (Which currently stands at a whopping 331 species, set in 1982.) A “Big Day” is a mix of fun and work that takes both passion and planning – this one is no exception. Here’s the Peru Big Day Strategy:

Peru is among the top countries in the world for bird diversity, with roughly 1840 species registered. This makes it a great place to attempt to beat the world big day record. The spectacular Andes Mountain range bisects Peru, and it is so tall that it passes through dramatically different climates between its base and its towering peaks. Each climate band produces it’s own habitat, which in turn has it’s own set of bird species. To the east of the Andes, much of Peru falls within the rainforests of the Amazon Basin, which contain the highest single-site bird diversity in the world. The key to a large list during our big day will be to visit as many habitat bands on the slopes of the Andes as possible, but also to spend enough time in the Amazon lowlands to see some of the many species in that area. In order to do this, we will start at midnight high in the Andes at Abra Patricia, work our way down the eastern slopes of the mountains during the morning, and finish in the afternoon in the Mayo Valley, home to many lowland Amazon bird species.

For more information, there’s a video by local TV station WBRZ, there’s a booklet from the American Birding Association or you can go straight to the horse’s mouth bird’s bill and check out http://www.lsubigday.org. Best of luck, you guys – Geaux Tigers!

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(From the LSU Peru Big Day webpage)