When two baboon troops go to war

An epic battle between hundreds of Hamadryas baboons is caught on camera by a BBC natural history film crew.

See original: Earth | Earth News When two baboon troops go to war

The downside of beauty [Gene Expression]

250px-Triumph_of_Achilles_in_Corfu_Achilleion.jpgWell, I don't quite know about that, but that's the sort of take-away from a new paper in PLoS Biology which looks at the downsides of female attractiveness. A Cost of Sexual Attractiveness to High-Fitness Females:

Adaptive mate choice by females is an important component of sexual selection in many species. The evolutionary consequences of male mate preferences, however, have received relatively little study, especially in the context of sexual conflict, where males often harm their mates. Here, we describe a new and counterintuitive cost of sexual selection in species with both male mate preference and sexual conflict via antagonistic male persistence: male mate choice for high-fecundity females leads to a diminished rate of adaptive evolution by reducing the advantage to females of expressing beneficial genetic variation. We then use a Drosophila melanogaster model system to experimentally test the key prediction of this theoretical cost: that antagonistic male persistence is directed toward, and harms, intrinsically higher-fitness females more than it does intrinsically lower-fitness females. This asymmetry in male persistence causes the tails of the population's fitness distribution to regress towards the mean, thereby reducing the efficacy of natural selection. We conclude that adaptive male mate choice can lead to an important, yet unappreciated, cost of sex and sexual selection.

The dynamic is well illustrated by the first figure:

journal.pbio.1000254.g001.png

The two lines above the shaded distribution illustrate variant male preference strategies. The solid lines shows random preference for females as a function of size, while the dashed line shows biased preference toward larger fitter females. The two lines below show the distribution of female fitness in response. In the case of the solid line you see the fitness of females in the context of random preferences; that is, males do not strongly prefer females who are fecund because of their large size. The reason that a large female may be more fecund is rather obvious, more physiological resources expendable upon the offspring. The evolutionary anthropologist Sarah Blaffer Hrdy claims the same principle is operative among humans in her book Mother Nature, larger females are less likely to miscarry and have complications, and can provide more robustly for their young. If one is healthy enough to construct a large and robust physique, one normally does so.

And yet as you can see above, strong male preference for these fecund females reduces their fitness. Male persistence from what I can tell might be colloquially termed "harassment." The energetic surfeit which larger females might allocate to their own reproductive output for provisioning has to be expended upon fending off males. In a context where males strongly prefer large females their fitness advantage is actually mitigated! This is a really weird outcome of sexual preferences.

The model rests on four primary assumptions:

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Also check out the featured ScienceBlog of the week: Neurotopia

See original: ScienceBlogs Select The downside of beauty [Gene Expression]

Journal of Happiness Studies - made my day. http://ff.im/cBjV0

EvoMRI: Journal of Happiness Studies - made my day. http://ff.im/cBjV0

See original: Twitter Journal of Happiness Studies - made my day. http://ff.im/cBjV0

Climate change report calls for passenger tax on flights to reduce CO2

8/12/2009 Gatwick would still operate with just one runway.Heavy taxes on passengers and a ban on expansion at regional airports will be needed to curb Britain’s insatiable appetite for air travel, a climate change report will say today .  But it will still be possible to build a third runway at Heathrow, add second runways [...]

See original: Resources for a sustainable future Climate change report calls for passenger tax on flights to reduce CO2

Malcom Gladwell on

Malcom Gladwell on Steven Pinker, Judith Rich Harris, Nassim Taleb: C-Span Interview by Brian Lamb [...] [...] TRANSCRIPT

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Creative Commons Casestudies, Featuring Status.Net

The Centre For Internet and Society and JAAGA organised a CC Salon on 02nd December, 2009 at 7.30pm.

See original: Home Page Creative Commons Casestudies, Featuring Status.Net

Water shortages forge huge market in Mumbai and the poor go thirsty

8/12/2009 BBC  The heat is scorching as the young woman knocks on the window of my taxi, though rather than begging for cash she points at my water bottle, then to her mouth.In a city where clean water has become a commodity that is delivered to the highest bidder, the poor often have to go without. [...]

See original: Resources for a sustainable future Water shortages forge huge market in Mumbai and the poor go thirsty

Prize Lectures in Economic Sciences, Dec. 8

Watch today's live webcast of Prize Lectures in Economic Sciences, 3:00 –4:20 p.m.CET.

Lecture titles: Beyond markets and states: polycentric governance of complex economic systems by Elinor Ostrom

The economics of governance by Oliver E. Williamson

See original: Nobelprize.org Prize Lectures in Economic Sciences, Dec. 8

Nobel Lecture in Chemistry, Dec. 8

Watch today's live webcast of Nobel Lectures in Chemistry 12:30–2:30 p.m CET.

Lecture titles: Decoding the genetic message: The 3D version by Venkatraman Ramakrishnan

From understanding ribosome structure and function to new antibiotics by Thomas A. Steitz

Polar bears, unpaved roads, Everest climbing and ribosomes in action by Ada E. Yonath

See original: Nobelprize.org Nobel Lecture in Chemistry, Dec. 8

Nobel Lecture in Physics, Dec.8

Watch today's live webcast of Nobel Lectures in Physics, 9-11:05 am CET.

Lecture titles:
Sand from centuries past send future voices fast by Charles K. Kao
Charles K. Kao's lecture will be held by Mrs Gwen Kao.

CCD – an extension of man's vision by Willard S. Boyle

The invention and early history of the CCD by George E. Smith

See original: Nobelprize.org Nobel Lecture in Physics, Dec.8

القمر الجليدي تيثيس من كاسيني



مالذي يعطي سطح تيثيس، أحد أقمار زحل، هذا الشكل الغريب؟ سؤال دفع ناسا لإرسال مركبة كاسيني الآلية بالقرب من هذا القمر الغامض سنة 2005. الصورة المرفقة من أدق الصور الملتقطة للقمر تيثيس. يعتقد أن لونه الأبيض راجع للتهاطل المستمر لجزيئات الجليد من الحلقة E الموجودة حول زحل، والتي يعتبر قمر إنسيلادوس مصدرها الرئيسي. بينما يبقى أصل بعض الأنماط التضاريسية مجهولا. التفحص الدقيق للصورة المرفقة للقطب الجنوبي لتيثيس تظهر مايشبه المجرى الجرفي يمتد قطريا من المركز يعرف باسم إيثاكا كازما (Ithaca Chasma). يرجح أن يكون هذا الفج تشكل نتيجة تجمد المحيطات الداخلية للقمر. إن صحت هذه النظرية، فإن القمر قد يحوي محيطات، ربما تكون شبيهة بتلك الموجودة في باطن القمر الآخر إنسيلادوس اليوم، وربما تخبئ معها حياة مجمدة؟

See original: Pixelpost القمر الجليدي تيثيس من كاسيني