Monthly Archives: August 2014

Is “epigenetics” a revolution in evolution?

There are a handful of examples showing that environmentally-induced changes can be passed from one generation to the next. In nearly all of these examples, the changes disappear after one or two generations, so they couldn’t effect permanent evolutionary change.

Adaptive changes in an organism — or any change that has been fixed in a species — rest on inheritance that is based on changes in the DNA.

See also http://doubtfulnews.com/2014/08/facepalming-article-suggests-darwin-may-fall-via-epigenetic-findings/ .

Why Evolution Is True

One often hears the suggestion that the neo-Darwinian view of evolution is on the skids, and that that view will be completely changed—if not overturned—by new biological ideas like modularity, genetic assimilation, evolvability, and epigenetics.  Epigenetics in particular (I’ll define it in a moment) has been especially touted as a concept that will revolutionize evolutionary biology.

Call me an old fogey, but I think the idea of epigenetics as a Darwin-destroyer is completely bogus.  Although certain discoveries in that area are interesting, and have certainly expanded our notion about how genes work, there is not the slightest evidence that the findings of epigenetics will dispel the main ideas of neo-Darwinism, which include the ideas of evolutionary change via natural selection and genetic drift, the randomness of mutations, the ideas of speciation and common descent, and the gene-centered view of evolution.  I’ve explained my views on epigenetics as a revolution in…

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Picture of the Day: Cumulonimbus Cloud over Africa

It’s not a UFO; it’s a Cumulonimbus cloud

TwistedSifter

Cumulonimbus Cloud over Africa

Photograph by NASA

[NASA April 21, 2010] Perhaps the most impressive of cloud formations, cumulonimbus (from the Latin for “pile” and “rain cloud”) clouds form due to vigorous convection (rising and overturning) of warm, moist, and unstable air. Surface air is warmed by the Sun-heated ground surface and rises; if sufficient atmospheric moisture is present, water droplets will condense as the air mass encounters cooler air at higher altitudes. The air mass itself also expands and cools as it rises due to decreasing atmospheric pressure, a process known as adiabatic cooling. This type of convection is common in tropical latitudes year-round and during the summer season at higher latitudes.

As water in the rising air mass condenses and changes from a gas to a liquid state, it releases energy to its surroundings, further heating the surrounding air and leading to more convection and rising of the cloud mass to higher…

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