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The agents of natural selection cause evolutionary changes in population gene pools. They include a plethora of familiar abiotic and biotic factors that affect growth, development, and reproduction in all living things.

The post The hidden side of natural selection appeared first on OUPblog.

As the 2016 presidential election season begins (US politics, unlike nature, has seasons that are two years long), we will once again see Republican politicians ducking questions about the validity of evolution. Scott Walker did that recently in response to a London interviewer. During the previous campaign, Rick Perry answered the question by observing that there are “some gaps” in the theory of evolution and that creationism is taught in the Texas public schools (it isn’t, of course).

The post The dangers of evolution denial appeared first on OUPblog.

Analyses of Neanderthal genomes indicate that when anatomically modern humans ventured out of Africa around 50,000 years ago, they met and mated with Neanderthals, probably in regions of the Eastern Mediterranean.

The post Meeting and mating with Neanderthals: good and bad genes appeared first on OUPblog.

Phew. It's the last day of March and I'm exhausted, but elatedly so (is it possible to feel both elated and exhausted concurrently?) I could scramble for my dictionary to check, but, to be honest, I'm just too tired. Instead, I am going to sit here in my comfy chair and tell you all about the month that was, and why I'm just so tired (and elated). To start with, the end of February saw me

Lana Goldsmith, Intern

John C. Avise is Distinguished Professor of Ecology and Evolutionary Biology at the University of California, Irvine.  His new book, Inside the Human Genome: A Case For Non-Intelligent Design, tackles the philosophical question of why humans are imperfect on the genetic level if made by a Creator God.  In this excerpt, Avise asserts that evolution is not random (as Intelligent Design proponents argue) due to natural selection.

Advocates of Intelligent Design contend that complex biological features cannot arise by chance, the implication being that chance equates to sentient forces.  From a scientific vantage, however, the driving force of adaptive evolution–natural selection– is itself the antithesis of chance.  Hereditary factors that promote organismal survival and reproduction in a particular environment tend to be precisely those that proliferate across the generations and thereby come to characterize natural populations.  Whenever genetic variation and differential reproduction exist in nature (as they do in all known species), natural selection is inevitable, both logically and empirically.  Biological traits that emerge from this inexorable operation may have the superficial aura of intelligent artistry, but that appearance is illusory (under a scientific interpretation).  Natural selection can be a highly creative process (given a suitable supply of genetic variation to work from), but it is merely a mechanistic phenomenon– as inescapable and insentient as gravity.

This is not to say that evolution is devoid of important stochastic (i.e. chance) elements.  Natural selection can sift only among the genetic variants available for its scrutiny, and two of the three primary sources of genetic variability– de novo mutation and recombination– occur essentially at random with respect to forging adaptations.  The new mutations and recombinant genotypes that arise in each generation have no biased tendency to enhance either an individual’s genetic fitness (its reproductive success relative to other individuals) or the adaptive needs of a species.  In other words, favorable alleles and more fit genotypes have no known mutational tendency to arise disproportionately when needed.  In this important sense, the genetic fodder upon which natural selection acts can indeed be characterized as stochastic or chancy in origin.

The third source of population genetic variation entails a mixture of “chance and necessity.”  Apart from de novo mutations and recombinant genotypes, the genetic variety available for natural selection in any generation is also a function of historical circumstance, that is, of idiosyncratic genealogical outcomes that have been affected by both stochastic and directive evolutionary processes across all prior generations.  Evolution going forward can work only with the biological substrates–”ghosts of evolution past”– are not supernatural legacies, but instead they are real genetic lineages and real species that have been subjected for eons to the full panoply of evolutionary processes including natural selection (the directive agent of adaptive evolution) as well as idiosyncratic mutation, recombination, and genetic drift (stochastic forces in the sense described above).

The temporal nature of heredity also means that evolu

Last night, I was feeling philosophical, but had nothing to ponder on. I looked at my PC and was struck with the sheer lack of technical expertise I had in electronics, rendering any opinion I had on the intricacies of the device around 10 years out of date. I started looking on Wikipedia, before feeling pretty belittled by my lack of knowledge of space physics. Then, inspiration hit me. Actually, it hit the window.

“Bzzzz. Whack. Bzzzzzz. Whack. Bzzzzz. Whack”. I looked around to try and locate the origin of such debacle, then I saw it. A fly was buzzing around, hitting off the window repeatedly.

I found myself at a fork in the path of destiny in my life. It would have been easy to ignore the offending beast and go back to my scholarship on the theorised negative pressures exhibited by dark matter. But no, unfortunately I chose the other path open to me: I concentrated on the fly.

Bzzzzzz. Whack. Bzzzzzz. Whack.

On watching the poor creature, I couldn’t help but admire its boundless stoicism and determination. However, the net feeling in my mind was not one of reckless pity. It was more a feeling of disappointment. I wasn’t disappointed in the fly: how could a creature that is probably less than a day old really understand the enormity of its stupidity? Rather, I was disappointed with evolution. I had really hoped that over two billion years of cumulative learning and development, the animal kingdom would have overcome such a barrier.

Image via Wikipedia

Evolution is always cited as such a wonderfully intelligent thing. Even as I write this, I can hear Richard Attenborough saying, “Look how the tree has learned to lean towards the sunlight.”. Of course there is far more to be said for evolution and its wonderful creations. But 2 billion years? I had really hoped for more.

Bzzzzzzz. Whack.

I was starting to get quite upset. If I was locked in a room the size of earth for 2 billion years, I would have expected to design a fly that could learn from its mistakes.

Bzzzzzzz. Whack.

The window was dirty, I noticed with increasing desperation. Surely the resultant deviation from transparency would register with the fly?

Bzzzzzzzz. Whack.

This was the last straw. I had to do it, I had to be the vector for natural selection. From that moment on, any offspring of the fly would spend their entire adult lives whacking into inanimate objects without the brainpower to overcome such a simple problem.

Bzzzzzz. Whack. I knew then, if I didn’t do it, the animal kingdom would be doomed. I reached for a newspaper. I rolled it up in my hands. The future of the world was in my hands.

Image via Wikipedia

Bzzzzzz. Whack. This only steeled my resolve. I made my move. The fly, with almost pre-cognitive reflexes, dodged to the side and flew away. Knowing that my newspaper probably created a pressure wave that aided the fly in its escape, I poked holes in my holy smiting tool, ready to continue in my role as God of evolution.

Bzzzzzzz. Whack. The fly was back. I leapt at it.

The ensuing struggle was too horrible to even describe. The bloodshed? Non-existent. The perspiration on my brow? Fairly prominent. The fly? Still alive. My curtains? In a heap on the floor. My desktop belongings? Scattered. My glass of coke? Spilt.

The fly had won. I slumped in a heap of desolation on the floor. I couldn’t help but wonder if the attempts to get through the window were simply an ingenious experiment to prove quantum theory (if you hit an object enough times you will go through it) or if the fly’s erogenous zones were on its forehead. Either way, the little bugger had won.

Bzzzzzzz. Whack. Back to trying to decipher space physics, I suppose.

Author: Babette Cole
Illustrator: Babette Cole
Published: 2001 Peachtree Publishers
ISBN: 1561452572 Chapters.ca Amazon.com

Growls, scowls and rowdiness meet high-brow how-to in this boisterous blend of rules and rule-breaking. Speaking of civility, we do apologize — this chat accidentally spirals into Babette Cole related babbling…

Other books mentioned:

• Mommy Never Told Me
• Dr. Dog