Tag Archives: evolution

Happy International Darwin Day!

Today is International Darwin Day and to celebrate I’m reading some excellent articles from the nice people at darwinday.org, starting with this referral page which acts as my one-stop go-to resource to which I send people who don’t think they know enough about evolution to make an informed decision about its existence. You might just want to skip to the Evolution 101 page.

Because we all want to be open-minded and educate ourselves, right? Because we are never too old to learn new stuff.

However, if you’re just not in the mood right now for those more time-consuming articles, you can watch the video on this page from PBS’s Nova about Darwin and evolution and how our understanding of it has changed since his time. Or any one of a number of these Ted Talks which explain some of the uncounted ways evolution shows itself on earth.

One of my favorites (below) talks about how humans might evolve to better survive long periods in space.

USC professor does a takedown of Ben Carson

Ben Carson Beat Operation jefferly.com
, USC Annenberg professor and Norman Lear Center director, takes an academic’s look at Ben Carson and is shocked at what he has seen:
When Wolf Blitzer asked Carson if he wanted to amend or take back his comparison of Obama’s America to Nazi Germany, he replied, “Absolutely not.”

Am I comparing Carson to Nazis? Absolutely not. I’m comparing the compatibility of a scientific education and intellectual ignorance with the compatibility of a humanistic education and moral ignorance.

The simple yet appalling fact is that we have at least some solid evidence that a top scientific education and a distinguished career in medicine does not make a man any less capable of believing untruths to be true and truths to be false.

I don’t know how I’d react if a shooter opened fire in my classroom. Maybe I’d risk my safety to protect others. Maybe I’d be too petrified do anything. But I do know the feeling that would devastate me if someone I loved became “a body with bullet holes”; it would not be the feeling that the Second Amendment is in jeopardy. It is at least conceivable that the clinical detachment required by a doctor to deal with the deaths in this room makes the deaths in the next room less urgent, less real.

I know plenty of physicians of whom that is not true. But when Ben Carson blames a mass murderer’s victims for failing to foil him, I know of at least one man of science whose capacity for moral response has been absorbed by fictions.

A good piece. And a total slapdown by one respected academic of a candidate who 1) has chosen to turn his back on his education for political purposes or 2) is so blinded by ideology he has lost all reason.

Source: Ben Carson, the Nutty Neurosurgeon | Marty Kaplan

When did our dogs become dogs?


Anyone who has a dog for whom they are the primary human in that dog’s life — the pack leader, the person that dog will most consistently follow even if two humans without food in their hands get up to leave a room at the same moment — can attest to the loyalty and love of a dog.

Anyone else who has lived with a dog or who has access to YouTube or a TV can also bear witness to the amazing abilities of dogs to adapt and learn a wide range of human-like abilities; everything from apparently singing to music while they pound piano keys, to jumping rope and solving simple shape-based puzzles.

Considering how much dog research is now happening on myriad fronts in respected universities around the world, it’s worth noting how short a time ago it was that science largely scoffed at the notion of studying dogs. Dog behavior that we now consider a sign of their intelligence and emotional inner lives was considered by most scientists to be a matter of genetics and evolution; not learned behavior but behaviors based in thousands of years of evolution from wild animals to dogs.

But a few scientists had already started considering the possibilities surrounding the fact that dogs are the only animal (aside from cats) that co-evolved in close, domestic contact with humans. This forced them to start looking at our unique relationship, including experiments beginning with the simple fact that humans point at things to indicate interest or an action to be taken, something scientists dubbed “referential intention.” dogs

Chimpanzees, our closest living relatives in the animal world, fail miserably at referential intention. If a chimpanzee knows you have food, yet you point at the place where you have put that food when the chimp was not looking, the chimp will simply stare at you bewildered.

Dogs ace these test because they — along with some domesticated cats — know what pointing means from living with us in close quarters for so long. This ability to understand referential intention is one of the reasons dog owners can endlessly amuse themselves by sitting on the couch with a ball in a hand they raise up as if they are going to throw it, but drop it behind the couch instead. The dog thinks your faked action of throwing the ball means the ball must be somewhere out there where you usually throw balls. 

They don’t have to see the ball flying through the air. They saw your arm “throwing” and that is all that is needed to send them on a confused chase. But if you then point behind the couch, most dogs will get through referential intention that the ball is where you pointed.

The same characteristics that allows we humans to understand referential intention has evolved in domesticated dogs alongside us. An action that most dog owners see as the simplest thing imaginable is actually a remarkable by-product of co-evolution. Even six-week-old puppies with no special training can understand pointing.

Another domesticated dog trait is the ability to understand and react to the utterance and inflection of the command “No!” dogs

If you have a steak on a table and a dog slowly creeps up and looks as if it will try to grab that steak, the command “No!” will cause most dogs to retreat — though generally not far.

If you do the same thing to a tail-wagging, face-licking non-domesticated wolf raised from a puppy, you can scream “No!” until you are out of breath and the wolf will simply grab the steak anyway while keeping a close eye on you while it is doing it.  Wolves don’t really care if you are scolding them. That steak is theirs.

(Note that people who work with wolves do not try to grab the purloined steak from a wolf’s mouth as they might do with a cocker spaniel.)

But none of these situations answer questions that are engaging research efforts around the world. Did we domesticate dogs or, in a manner of speaking, did dogs domesticate us?

Put another way: did early humans discover that if you raised wild dogs from puppies they made good hunting animals and pets? Or did wild dogs slowly discover that if they hung around humans without attacking them, they could find warmth, food scraps and the like?

These questions have proven difficult to answer since all we have are archeological sites dating back tens of thousands of years which show clearly that dogs or dog-like creatures have been a part of our lives for a very long time. Some sites have had grave sites which contained the remains of a human and a dog with artifacts suggesting the burial was an honorable one for both human and beasts. There appear to have been dog lovers going back to very ancient times.

dogsBut how can we know with any accuracy when the dogs were domesticated?

As it turns out the ability to breed behavioral and genetic traits in and out of dogs so quickly can give us that answer — making a Pug as opposed to a Dachsund, or controlling genetically for friendliness or the ability to hunt.

Scientists have discovered if you breed wild canines (foxes, for example) and control successive generations only for friendliness and no physical characteristics whatsoever, an amazing thing happens. Foxes start to look like dogs. Floppy ears, shorter snouts; the range of physical characteristics which make dogs look like dogs.

Domesticated canines don’t need the pointy ears (for extra sensitive hearing) and long snouts (housing lots of long, sharp teeth; crushing jaw muscles and a top-level carnivore’s sense of smell). So these things start to dull in dogs whose every meal is handed to them. Knowing this happens will help researchers ascertain whether dog skulls found at burial sites were dogs that were domesticated or canis which were present for other reasons.

Their brains change, too, as this article from this month’s special issue of Scientific American (note: paywall)  points out:

These kinds of anatomical changes are the first signs of domestication, Germonpré and others say.

Similar changes are found in the skulls of the silver foxes that are the focus of a famous, long-running experiment at Novosibirsk State University in Russia. Since 1959 researchers there have selected the foxes for tameness and bred them. Over the generations their coats have become spotted, their ears floppy, their tails curly, their snouts shorter and wider—even though the scientists have been selecting only for behavior. Similar changes are seen in other domesticated species, including rats and mink. Investigators have yet to explain why docile animals are consistently altered in these ways. They do know that the tame silver foxes have smaller adrenal glands and much lower levels of adrenaline than their wild counterparts.

Last year other scientists came up with a testable hypothesis: tame animals may have fewer or defective neural crest cells. These embryonic cells play a key role in the development of the teeth, jaws, ears and pigment-producing cells—as well as the nervous system, including the fight-or-flight response. If they are right, then all those cute domestic traits—spotted coats, curly tails, floppy ears—are a side effect of domestication.

Germonpré believes that the apparent domestication at Pˇredmostí was a dead-end event; she doubts that these animals are related to today’s dogs. Nevertheless, to Germonpré, “they are dogs—Paleolithic dogs.” She says these early dogs probably looked very much like today’s huskies, although they would have been larger, about the size of a German shepherd. Germonpré calls the Pˇredmostí specimens “dogs” because of what she interprets as some type of relationship between the canids and the Gravettians. For instance, a dog’s lower jaw was found near a child’s skeleton, according to the diary of the original excavator.

The dogs were also included in rituals in ways that other species were not. In one case, a Gravettian tucked what is most likely a piece of mammoth bone between the front teeth of one of the dog skulls after the animal died and arranged its jaws so that they clamped together on the bone. Germonpré suspects that an ancient mammoth hunter placed the bone there as part of a ritual related to hunting, or to help sustain in death an animal the hunter revered, or to enable the dog to assist a human in the afterlife. “You see this kind of thing in the ethnographic record,” she says, citing, as one example, a Chukchi ceremony in Siberia for a deceased woman in the early 20th century. A reindeer was sacrificed and its stomach placed in the mouth of a dead dog’s head, which was then positioned to protect the woman on her death journey.dogs

Many researchers imagine that these early people set about making the wolf into the dog to help us hunt big game. In her book The Invaders, published by Harvard University Press earlier this year, anthropologist Pat Shipman argues that the first dogs (or wolf-dogs, as she calls them) were like a new and superior technology and helped the mammoth-hunting modern humans outcompete the Neandertals. But she, Wayne, Larson and others think that wolves joined forces with humans on their own; that the canny, adaptable canids identified us as a new ecological niche they could exploit. The alternative scenario—people brazenly raiding wolf dens to steal pups young enough for taming—would have been a dangerous undertaking. And raising wolves in camps with young children would have presented another serious risk.

“We didn’t do [domestication] deliberately—not at first,” Larson surmises. Instead wolves most likely started following people for the same reason that ants trail into our kitchens—“to take advantage of a nutritional resource, our trash.” Over time some of these camp-following wolves increasingly lost their fear of people—and vice versa—and a mutually beneficial relationship developed. Wolf-dogs would sniff out prey for us, and we would share the resulting meat with them. (Circumstantial evidence for this scenario comes from the silver fox experiment. By selecting foxes that were less fearful of humans, the researchers at Novosibirsk eventually developed a silver fox that runs to greet people. Most silver foxes in captivity hide in the back of their cage.)

Pretty amazing stuff if you are, as I am, an unabashed fan of all things dog.

Source: New Clues about the Evolution of Dogs – Scientific American

So much ignorance in one sign


Evolution is real…and it goes in reverse

Proof that evolution can be reversed