Category Archives: Nothing in Biology Makes Sense

Nothing in Biology Makes Sense: Making sense of the evolution of language

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The language of evolution. Photo by CharlesFred.

This week at the collaborative blog Nothing in Biology Makes Sense, guest contributor James Winters describes the considerable inter-relationships between evolutionary biology and the study of human language.

Darwin recognised, along with several other linguists of the period such as August Schleicher and Mikołaj Kruszewski, that language falls under the remit of evolutionary principles. Since then, there has been a renewed and growing interest in evolutionary (Croft, 2000) and ecological (Mufwene, 2000) theories of language change, with biological, cultural and linguistic forms of evolution being captured by the more general rubric of Complex Adaptive Systems. … it is the capacity to evolve and adapt that differentiates language and biology from these other systems, with the key concept being their ability to learn: past experiences filter through, or influence, future states of the system due to cumulative amplification dynamic (Deacon, 2010).

To find out more, go read the whole thing. ◼

Nothing in Biology Makes Sense: Cardiothoracic surgery

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Photo by akeg.

This week at the collaborative science blog Nothing in Biology Makes Sense, my brother Jon, a third-year med school student, describes his experiences helping out with open-heart surgery:

I stood on the other side, holding the still-beating heart out of the way. I couldn’t help but be amazed at the calm at which they did this, as if this were a perfectly normal and ordinary thing to do. Then, once all the lines were in place, a clamp was placed on the aorta, completely isolating the heart from the circulation of blood in the rest of the body. At this point, the heart is cooled down with ice and infused with a solution that arrests it in the phase of contraction called diastole. This is when the timer starts: From this point on the surgeon can operate for up several hours without any damage occurring to the heart.

For all the (not actually very gory) details, go read the whole thing. ◼

Nothing in Biology Makes Sense: Making sense of spiteful bactera

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Photo by Iluisanunez.

This week at the collaborative science blog Nothing in Biology Makes Sense!, contributor Devin Drown discusses a new study of bacterium-on-bacterium violence:

The bacteria produce chemical weapons, bateriocins, which can broadly harm other isolates, but relatives are left unharmed. These chemical weapons can be classified as spiteful: in the process of harming others they also harm the focal individual. This self-harm comes from the cost of making the chemical weapon. Others have labeled this antagonistic trait a greenbeard gene.

To learn what a bacterial chemical weapon has to do with what might otherwise sound like an overenthusiastic celebration of Saint Patrick’s Day—and how both might explain the diversity of living populations, read the whole thing. ◼

Nothing in Biology Makes Sense: Making sense of sex

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Host-parasite coevolution is like a box of chocolates … Photo by HAMACHI!.

I’m not a particularly big fan of Valentine’s Day, but Nothing in Biology Makes Sense! contributor C.J. Jenkins really, really is. She’s marking the day with chocolate, red wine, and a new mathematical model explaining the evolution of sex:

There have been a number of different mechanisms of selection that have been proposed to explain sex: host-parasite interactions (Bell 1982), elimination of deleterious alleles (Mueller 1964), and various forms of selection (Charlesworth 1993; Otto and Barton 2001; Roze and Barton 2006). However, none of these alone are able to theoretically overcome the two-fold cost of producing males, so many biologists have started taking a pluralist approach (West et al. 1999; Howard and Lively 1994) and combing one or more of the advantages to being sexual in an effort to understand why the birds do it, the bees do it, and even educated fleas do it.

To learn how a new study revives the longstanding “Red Queen” theory—that sex is beneficial because sexually-produced offspring are more likely to carry genes that can help fight off parasites—go read the whole thing. ◼

Nothing in Biology Makes Sense: Making sense of ubiquitous plant defenses

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A giraffe, dodging thorns like a pro. Photo by Colin Beale, via Nothing in Biology Makes Sense.

We have a second post at the collaborative blog Nothing in Biology Makes Sense! this week, in which ecologist Colin Beale (guest posting from Safari Ecology) tackles the question of why so many African savannah plants grow thorns:

At one level the answer is obvious—there are an awful lot of animals that like to eat bushes and trees in the savanna. Any tree that wants to avoid this would probably be well advised to grow thorns or have some other type of defence mechanism to protect itself. But then again, perhaps the answer isn’t so obvious: all those animals that like to eat bushes seem to be eating the bushes perfectly happily despite the thorns. So why bother having thorns in the first place?

To find out why, and see more of Colin’s great photos, go read the whole thing. ◼

Nothing in Biology Makes Sense: Making sense of inbreeding depression

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Bighorn sheep. Photo by Noah Reid, via Nothing in Biology Makes Sense.

This week at the collaborative blog Nothing in Biology Makes Sense!, Noah Reid returns to discuss the bane of small, isolated populations: inbreeding depression:

Iconic North American species such as grizzly bears, red-cockaded woodpeckers, and the American burying beetle today inhabit only small fractions of the ranges they occupied only 100 years ago. A result of this fragmentation is that many individuals exist in small, isolated populations. In these populations, a curious phenomenon often emerges, one that can only be understood in light of some basic evolutionary theory.

To find out more about that phenomenon, and when it can become hazardous to a population’s health, go read the whole thing. ◼

Nothing in Biology Makes Sense: notes from the field

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Snails crossing. Photo via Nothiing in Biology Makes Sense.

The latest post at the collaborative blog Nothing in Biology Makes Sense is from contributor C.J. Jenkins, who describes the fieldwork that’s taken her to the ends of the earth. Or, well, New Zealand, anyway.

A little over a quarter century ago, Curt Lively, noted this adorable little New Zealand snail (Potamopyrgus antipodarum) has sexual and asexual forms that coexist at varying frequencies in lakes across New Zealand. This variation suggests that there are some environments where it is advantageous to reproduce asexually and some environments where it is better to be sexual.

From then on P. antipodarumhas become an excellent system to study the evolution and maintanence of sexual reproduction, a long standing debate in evolutionary biology

Go read the whole thing.

Want to contribute to NiB? Drop me an e-mail and tell me what you want to write about. ◼

Nothing in Biology Makes Sense: Making sense of the origins of multicellularity

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Experimental evolution of multicellularity. Photo by Nothing in Biology Makes Sense!

In this week’s new post at the group blog Nothing in Biology Makes Sense!, Sarah Hird discusses the recently published experimental evolution study that used laboratory yeast to tackle one of the biggest questions in reconstructing the history of life:

Some of the biggest questions in evolutionary biology deal with the origin of life. For example, if I go back one generation, I find my parents. Two generations, my grandparents. Ten generations are human beings who may or may not have looked like me. Five hundred thousand are, oh, I don’t know. Maybe a bipedal hominid? Anyway, if we continue going backward like this, we inevitably get to time zero and encounter some big-time questions that can really cause a brain to cramp up.

I promise you, if you read the whole thing, you will not experience brain cramps. Quite the opposite, in fact.

In other news, Nothing in Biology Makes Sense! has put out a call for guest contributors. If you work in biology—anything from medicine to plant breeding—and you’ve been thinking about giving this science blogging thing a try, send us an e-mail!&nbsp ◼

Nothing in Biology Makes Sense: Did humans send North America’s large mammals to extinction?

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Are ancient humans to blame for mammoths’ extinction in North America? Photo by W9NED.

After a beginning-of-semester scheduling hiccup, the group blog Nothing in Biology Makes Sense! is up and running for the spring, starting with a great post by contributor Noah Reid. Noah breaks down a big, complex study that applied species distribution modelling, paleontological data, and ancient DNA analysis to try and determine whether humans were responsible for the mass extinction of North America’s ancient large mammals.

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 find out, go read the whole thing. ◼

Nothing in Biology Makes Sense: Tracing the evolutionary history of HIV infection

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The molecular structure of HIV. Photo by PHYLOMON!.

In the latest post at the group blog Nothing in Biology Makes Sense!, contributor Luke Swenson describes how biologists can reconstruct the evolutionary history of HIV to estimate when the virus make the jump from chimps to humans, or even when a single patient became infected.

Although HIV evolves rapidly, it does so at a fairly constant rate. In essense, you can use this constant rate to act like a clock to tell you roughly how many changes accumulate over a year. Then, by figuring out the number of changes it would take for both sequences to converge on a single identical sequence (their most recent common ancestor, “MRCA”), you can get an estimate of the date that the MRCA existed at.

This is one of the best cases I know about in which evolution directly informs medical practice and treatment, and it’s well worth reading the whole thing. ◼