The evolution perspective: Do antidepressants do more harm than good?

Posted on April 30, 2012 by

The popular antidepressant drug Prozac (Image via Wikipedia).

A review of the pros and cons of antidepressant medication for treatment of major depression appeared this past week in the journal Frontiers in Evolutionary Psychology. The authors, Paul W. Andrews, J. Anderson Thomas Jr., Ananda Amstadter, and Michael C. Neale, use an evolutionary perspective combined with medical data to evaluate whether prescribing antidepressants should be the first choice of doctors to treat depression, as it currently is. They conclude that antidepressant medication can do more harm than good, and should be reserved for only the most serious cases (you can read the full text here).

The authors point out that most antidepressant drugs disrupt the way the neurotransmitter serotonin is used in the brain. Since serotonin is very conserved across evolutionary time (it evolved at least 1 billion years ago), and it is involved in many important processes in the body, disrupting it could have major negative effects. Some of these effects are: causing neuronal damage, bleeding, stroke, low blood sodium, and adverse sexual effects. Continue reading →

Posted in Human sex, Sex and society | Tagged , , , , | 1 Comment

Sex or no sex, that is the question

Posted on April 21, 2012 by

My lovely spider plant, trying to reproduce sexually and asexually. Make up your mind!

There are pros and cons to everything in life, and sex is no exception. From an evolutionary biology standpoint, sex is a compromise (which may explain why so many of our lawmakers seem to be against it).

Reproducing asexually means you don’t have to share with anyone else: all your genes get packed into each offspring and carried off into future generations. On the other hand, it’s the equivalent of putting all your eggs in one basket. If a disease comes along that your particular set of genes can’t fight against, all your offspring will be wiped out–the  ”game over” of evolution.

So, sex is used to add variation into the gene sets of all your kids. You can’t pass on all your genes to every kid, but there’s less chance they’ll all be killed off by the same strain of the flu (See: Red Queen hypothesis).

Abstaining from sex in order to pump out clones of yourself also means your genes never get a chance to fix themselves if they suffer a damaging mutation. Genes are fixed by using someone else’s genes as a template. Over time, if enough mutations build up, your genes may simply cease to exist in the population because they just don’t work anymore (See: Muller’s Ratchet).

But some species seem to thrive without sex, gene mutations be damned. Like flatworms. Continue reading →

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Male pygmy hippos control sex ratio with their sperm

Posted on April 1, 2012 by
You're still my mum

6 month old pygmy hippo Monifa snuggling up to her keeper at the Taronga Zoo. Image by myopixia via Flickr.

Okay, I’ll admit it: I’m using this paper as an excuse to post pymy hippopotamus pictures. They’re so cute! It’s also a nice distraction from what I am actually supposed to be working on: my thesis. My posts will continue to be sporadic for the next couple of months while I focus on, finally, getting this Ph.D.

Besides the cuteness of miniature hippos, the science in this paper is also really cool. Joseph Saragusty and colleagues at the Leibniz Institute for Zoo and Wildlife Research, along with Tim Bouts of the Zoological Society of London discovered that male pygmy hippos can control the ratio of female-to-male offspring they father. The paper was published in the February 28 issue of Nature Communications. Continue reading →

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Mama’s boys: How fig wasp mothers protect their sons

Posted on March 10, 2012 by

Fig wasps inside a fig. The love-children of an insect-plant romance.

I recently read this paper about fig wasps. Then I took some aspirin, put a cold press to my head, and had a nap. You may have seen my one other post about plants, so you might already know about my deep-seated distrust of the vegetable kingdom, rooted in my lack of understanding of plant biology.

The paper by Hui Yu and Stephen G. Compton was published in PLoS One. But it’s more than just a scientific paper. It’s a love story: fig and wasp, destined to be together and mutually dependent on each other for continued survival. It’s also about the love of a mother for her sons. And every love story has its tragedy. In this case, it’s the free-loading enemy wasps that kill the love-children of the wasp/fig romance and force the wasp mother to choose which children to protect.

I had a pretty good grasp on the animal side of this interspecies sex story: female fig wasps (who have to lay their eggs inside of figs–I’ll get to that in a bit) lay eggs containing sons in flowers that end up closer to the center of the fig. This leaves the daughters on the periphery where they are more exposed to attacks by enemies. Protecting the boys ensures that there will be enough males in the next generation, since males are naturally rarer than females.

But what’s all this fig business? Continue reading →

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Beetle moms benefit from absentee dads

Posted on February 29, 2012 by

Nicrophorus vespilloides. Image via Wikipedia.

What’s good for the goose ain’t always good for the gander–until it is.

In evolutionary biology-speak, sexual selection happens when one sex benefits from something that harms the other. For example, male seed beetles use their spiky penises to transfer as much sperm as possible during mating, but as you might imagine, those spikes aren’t as popular with the ladies. When this kind of conflict occurs, the “losing” sex may evolve counter-measures to try to even the playing field (like vaginal spikes in the seed beetle).

But who are we to say what works for a beetle? Instead of fighting back, the “losing sex” may actually adapt to the sub-optimal situation–until it becomes the optimal situation. Think of it as making lemonade when life hands you lemons. And then becoming dependent on lemonade.

In the burying beetle, Nicrophorus vespilloides, parents put a lot of effort into raising their young. Often, it seems to be too much effort for the dads, and they simply take off, in search of new ladies to knock up and desert. Sounds pretty bad for the moms, right? Scientists at the University of Cambridge wanted to know just how bad this scenario is for a single beetle mom. Research carried out by Giuseppe Boncoraglio and Rebecca M. Kilner found that actually, mom’s better off without him. The study was published Feb. 15 in the journal PLoS One. Continue reading →

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