Category Archive 'Evolution'

23 Aug 2018

Hybrid Python Supersnake?

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The Miami Herald reports scholarly speculation on the results of python cross-breeding in the Florida Everglades.

What started out as a straightforward genetic study of Florida’s invasive python population has turned up a surprising plot twist: a small number of crossbred Burmese and Indian pythons with the potential to become a kind of Everglades super snake.

For the study, published Sunday in the journal Ecology and Evolution, U.S. Geological Survey researchers examined the tail tissue of 400 snakes captured in South Florida, from the Big Cypress Swamp to the Everglades. While the vast majority appeared to be closely related Burmese pythons — imagine a family reunion packed with first and second cousins — 13 had genetic markers from Indian pythons, a different species that unlike the swamp-loving Burmese snake prefers high, dry ground.

The number is clearly small, but it raises the risk that over time some Everglades snakes could become better suited to a more varied landscape. Scientists call it hybrid vigor.

Python hunter Dusty Crum carries a python caught as part of South Florida Water Management District licensed hunting program in May. The state has been paying a select group of hunters to kill the invasive snakes on state lands since March 2017.

“If the Indian pythons have a wider range, perhaps these Everglades snakes now have that capability,” said lead author and USGS geneticist Margaret Hunter. “It’s quite interesting and quite surprising, but we don’t know the extent it’s in the population.”

RTWT

30 Jul 2013

Not Only From the Apes…

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Ingrid Newkirk of PETA contends that, really, “A Rat Is a Pig Is a Dog Is a Boy.”

Newkirk’s pig=boy equivalence receives support from Phys.Org, which links a scientific blog-site listing a long series of anatomical comparisons, which it argues constitute evidence that human beings do not only descend from apes.

Dr. Eugene McCarthy is a Ph.D. geneticist who has made a career out of studying hybridization in animals. He now curates a biological information website called Macroevolution.net where he has amassed an impressive body of evidence suggesting that human origins can be best explained by hybridization between pigs and chimpanzees. Extraordinary theories require extraordinary evidence and McCarthy does not disappoint. Rather than relying on genetic sequence comparisons, he instead offers extensive anatomical comparisons, each of which may be individually assailable, but startling when taken together. Why weren’t these conclusions arrived at much sooner? McCarthy suggests it is because of an over-dependence on genetic data among biologists. He argues that humans are probably the result of multiple generations of backcrossing to chimpanzees, which in nucleotide sequence data comparisons would effectively mask any contribution from pig.

Generally speaking, interspecies hybrids—like mules, ligers (lion-tiger hybrids), or zedonks (zebra-donkey hybrids)—are less fertile than the parents that produced them. However, as McCarthy has documented in his years of research into hybrids, many crosses produce hybrids that can produce offspring themselves. The mule, he notes, is an exceptionally sterile hybrid and not representative of hybrids as a whole. When it comes time to play the old nuclear musical chairs and produce gametes, some types of hybrids do a much better job. Liger females, for example, can produce offspring in backcrosses with both lions and tigers. McCarthy also points out that fertility can be increased through successive backcrossing with one of the parents, a common technique used by breeders. In the case of chimp – pig hybridization, the “direction of the cross” would likely have been a male boar or pig (Sus scrofa) with a female chimp (Pan troglodytes), and the offspring would have been nurtured by a chimp mother among chimpanzees (shades of Tarzan!). The physical evidence for this is convincing, as you can discover for yourself with a trip over to macroevolution.net.

When I asked McCarthy if he could give a date estimate for the hybridization event, he said that there are a couple broad possibilities: (1) It might be that hybridization between pigs and apes produced the earliest hominids millions of years ago and that subsequent mating within this hybrid swarm eventually led to the various hominid types and to modern humans; (2) separate crosses between pigs and apes could have produced separate hominids (and there’s even a creepy possibility that hybridization might even still be occurring in regions where Sus and Pan still seem to come into contact, like Southern Sudan).

This latter possibility may not sound so far-fetched after you read the riveting details suggesting that the origin of the gorilla may be best explained by hybridization with the equally massive forest hog. This hog is found within the same habitat as the gorilla, and shares many uncommon physical features and habits. Furthermore, well-known hybridization effects can explain many of the fertility issues and other peculiarities of gorilla physiology.

Read the whole thing.

Via the Dish.

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In the film “Gettysburg” (1993), on the evening of July 2nd, Confederate Corps Commander James Longstreet, Divisional Commander George Pickett and his Brigade Commanders Kemper and Armistead, discuss Charles Darwin’s new scientific theory of Evolution. Personally, I think General Pickett gets the best of the argument.

16 Jun 2012

Harvard Prof: Evolution Endorses Nanny-State Coercion

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Daniel E. Lieberman, Professor of Human Evolutionary Biology, Harvard University

It was not for nothing that the late William F. Buckley, Jr. declared: “I would rather be governed by the first two thousand people in the Boston telephone directory than by the two thousand people on the faculty of Harvard University.”

Daniel E. Lieberman, a Harvard-educated Anthropologist who has managed to segue smoothly from his native social science to teaching Evolutionary Biology, won recent top marks in Scientism, the inappropriate and hubristic application of scientific theories to political and moral issues, when in a New York Time’s editorial last week, he informed readers that Evolution was voting in favor of Mayor Bloomberg’s soft drink ban specifically and government coercion in general.

Lessons from evolutionary biology support the mayor’s plan: when it comes to limiting sugar in our food, some kinds of coercive action are not only necessary but also consistent with how we used to live. …

Since sugar is a basic form of energy in food, a sweet tooth was adaptive in ancient times, when food was limited. However, excessive sugar in the bloodstream is toxic, so our bodies also evolved to rapidly convert digested sugar in the bloodstream into fat. Our hunter-gatherer ancestors needed plenty of fat — more than other primates — to be active during periods of food scarcity and still pay for large, expensive brains and costly reproductive strategies (hunter-gatherer mothers could pump out babies twice as fast as their chimpanzee cousins).

Simply put, humans evolved to crave sugar, store it and then use it. For millions of years, our cravings and digestive systems were exquisitely balanced because sugar was rare. Apart from honey, most of the foods our hunter-gatherer ancestors ate were no sweeter than a carrot. The invention of farming made starchy foods more abundant, but it wasn’t until very recently that technology made pure sugar bountiful.

The food industry has made a fortune because we retain Stone Age bodies that crave sugar but live in a Space Age world in which sugar is cheap and plentiful. …

We humans did not evolve to eat healthily and go to the gym; until recently, we didn’t have to make such choices. But we did evolve to cooperate to help one another survive and thrive. Circumstances have changed, but we still need one another’s help as much as we ever did. For this reason, we need government on our side, not on the side of those who wish to make money by stoking our cravings and profiting from them. [Emphasis added] We have evolved to need coercion.

Professor Lieberman neglects to explain how Evolution effectively draws the line between acceptable, desirable, and morally justifiable forms of state coercion, including taxes, regulations, and special paternalistic supervision of children, and even more effective and draconian measures, for instance, the Khmer Rouge marching the overweight urban inhabitants of Cambodia back into the country at machine gun point, aimed at “restoring a natural part of our environment. ”

He doesn’t offer any general principled account of why Evolution supports this and doesn’t support that precisely because he hasn’t got one. Professor Lieberman simply assumes that Evolution and Science (and Progress and the God of History) is embodied in the world by the consensus of people like himself, by the current opinions of the educated elite community of fashion.

One can find the scientific way of deciding things simply by reading the editorial pages of the Times.

All this, of course, is rubbish. The opinions and theories of Evolutionary Biology (let alone Anthropology) are anything but set in stone. Someone may discover next week the intense Neolithic cultivation of sugar beets in the Fertile Crescent. Medicine may decide that obesity is really caused by a particular gene, and that the specifics of diet play only a small role.

In the 1950s, Evolution would have decreed that you must drink milk to cure ulcers produced by the unnatural stress of modern capitalist life. Our latest information contends that bacteria are to blame and milk-drinking doesn’t do a thing.

More importantly, though, mere scientific facts are incapable of addressing philosophical questions of individual rights and the proper role and limits of the powers of government. Those issues have nothing to do with imaginary dietary teleologies and have to be debated on an entirely different level.

Scientism, the presumptuous attempt to misapply scientific theories or data in contexts in which they cannot possibly be determinative, is actually, I would argue, decisive evidence of bad education and intellectual incompetence.

It has been recognized for many decades now, certainly back to the 1960s or 1970s when Bill Buckley offered his famous apothegm concerning the faculty of Harvard, that there exists a tremendous and thoroughly alarming disconnect between our establishment intelligentsia and wisdom and common sense. Professor Lieberman is simply the most recent in a long series of wise fools.

16 Nov 2009

Dandelion Or Orchid?

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Are you a genetically a dandelion or an orchid? Both have their place in the evolutionary scheme of things according to a recent article in the Atlantic by David Dobbs.

Most of us have genes that make us as hardy as dandelions: able to take root and survive almost anywhere. A few of us, however, are more like the orchid: fragile and fickle, but capable of blooming spectacularly if given greenhouse care. So holds a provocative new theory of genetics, which asserts that the very genes that give us the most trouble as a species, causing behaviors that are self-destructive and antisocial, also underlie humankind’s phenomenal adaptability and evolutionary success. With a bad environment and poor parenting, orchid children can end up depressed, drug-addicted, or in jail—but with the right environment and good parenting, they can grow up to be society’s most creative, successful, and happy people.

Hat tip to Bird Dog.


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