Category: Evolution

Human Species Is Highly Adaptable to Climate Variation

(p. A15) In “Evolution’s Bite,” paleoanthropologist Peter S. Ungar follows the stories encapsulated in our enamel-coated anatomy.
Mr. Ungar’s story isn’t so much about teeth themselves as about the sweeping tale of human evolution as seen through the mouth.
. . .
Unpredictability in climate and resources, Mr. Ungar emphasizes, has made us a species adapted to variation. Drawing from the work of researchers like Elisabeth Vrba and Rick Potts, he underscores how environmental shifts influence our evolution just as they have for other animals. The invention of culture did not somehow free us from nature. Our existence and continuing evolution are still influenced by shifts in climate and their effects. Humans didn’t become locked into just one narrow mode of life but rather became a flexible species as comfortable above the Arctic Circle as on the equator. “Climate change,” he writes, “drove human evolution, in large part by swapping out food options available on the biospheric buffet.”
This new story–that humans became adapted to the variability of the world rather than any one set of conditions–hasn’t had time to become pop-culture canon just yet. Images of Man the Hunter stepping out onto the savanna in search of big game still dominate. “The story used to be simpler,” Mr. Ungar writes, when it seemed that “the spreading savanna coaxed our ancestors down from the trees, and the challenges it brought made them human.” All the same, the mounting swell of research doesn’t show a slow and steady transition from a chilly Ice Age world to the warmer one we know today. Instead, Mr. Ungar points out, temperatures dipped and spiked in a haphazard pattern prior to our influence on the climate, having an overall trajectory that we can detect now but that probably would have seemed simply chaotic to the people and creatures living through it.

For the full review, see:
Brian Switek. “BOOKSHELF; Chewing Over History.” The Wall Street Journal (Weds., May 31, 2017): A15.
(Note: ellipsis added.)
(Note: the online version of the review has the date May 30, 2017, and the title “BOOKSHELF; Chewing Over Humanity’s History.”)

The book under review, is:
Ungar, Peter S. Evolution’s Bite: A Story of Teeth, Diet, and Human Origins. Princeton, NJ: Princeton University Press, 2017.

“Unfettered Science, If We Have the Courage to Let It Unfold”

(p. 26) “How to Tame a Fox” sets out to answer a simple-seeming question: What makes a dog a dog? Put another way, how did an animal that started out as a bloodthirsty predator become one that now wants nothing more than a nice belly rub and the chance to gaze adoringly at a member of another species? In the late 1950s, a Russian scientist named Dmitri Belyaev decided to address this puzzle by taking the unheard-of tack of replicating the domestication process in real time. He and his colleagues took silver foxes, widely bred in vast Siberian farms for their luxurious pelts, and made them into friendly house pets. It was a deceptively simple process: Take the puppies from only the friendliest foxes, breed them and repeat. Lyudmila Trut, the current lead researcher of the silver fox experiment, who began work as Belyaev’s intern, along with Lee Alan Dugatkin, an American scientist and writer at the University of Louisville, documents their monumental effort in this sparkling new book.
Belyaev died in 1985, but the experiment is still ongoing, with 56 generations of foxes bred to date — a far cry from the snarling creatures that used to snap at the hands of their caretakers when the research began. The new foxes run toward people, jump on the bed and nuzzle one another as well as their human caretakers. Such a behavioral transformation was to some degree expected, since they were bred from the tamest members of their groups. Perhaps more intriguing, they also look more doglike, with floppy ears, wagging tails and piebald fur.
. . .
The book, . . . , is not only about dogs, or foxes, or even science under siege from political interests. . . . It may serve — particularly now — as a parable of the lessons that can emerge from unfettered science, if we have the courage to let it unfold.

For the full review, see:
MARLENE ZUK. “Fox and Friends.” The New York Times Book Review (Sun., MAY 7, 2017): 26.
(Note: ellipses added.)
(Note: the online version of the review has the date MAY 5, 2017, and has the title “How Do You Make a Fox Your Friend? Fast-Forward Evolution.”)

The book under review, is:
Dugatkin, Lee Alan, and Lyudmila Trut. How to Tame a Fox (and Build a Dog): Visionary Scientists and a Siberian Tale of Jump-Started Evolution. Chicago: University of Chicago Press, 2017.

The Octopus, Though Intelligent, Only Lives for Two Years

(p. C5) Around 600 million years ago there lived in the sea a small unprepossessing worm, virtually eyeless and brainless. For some reason this species split into two, thus seeding the vast zoological groupings of the vertebrates and the invertebrates. On one branch sit the mammals; on the other sit the molluscs (and many others). Among these two groups, two notable creatures eye each other warily: the human and the octopus. They have no common ancestor apart from that lowly worm, yet there is a strange affinity, a bond almost. For they are both evolutionary experiments in intelligence–pockets of genius in a vast ocean (sorry!) of biological mediocrity.
In “Other Minds,” Peter Godfrey-Smith, a philosopher at CUNY and an avid scuba diver, has given us a smoothly written and captivating account of the octopus and its brethren, as observed by humans. He celebrates the cephalopods: the octopus, the squid and the cuttlefish. He stresses their dissimilarity to us and other mammals, but he also wants us to appreciate what we have in common. Just as eyes have evolved independently in many lineages, so have intelligent minds. From those mindless worms, via two separate evolutionary paths, to the glories of consciousness and curiosity–we are brothers in big brains.
. . .
(p. C6) Mr. Godfrey-Smith mixes the scientific with the personal, giving us lively descriptions of his dives to “Octopolis,” a site off the east coast of Australia at which octopuses gather. There they make their dens in piles of scallop shells. He also reproduces some excellent photographs of the octopuses and other cephalopods he has observed in his submerged city. It is with a jolt, then, that he announces the average life span of the cephalopod: one to two years. That’s it: That marvelous complex body, the large brain, lively mind and amazing Technicolor skin–all over so quickly. There are boring little fish that live for 200 years, and the closely related nautilus can live for 20 years, but the octopus has only a year or two to enjoy its uniqueness. Mr. Godfrey-Smith speculates that the brevity results from a lifestyle that forces the animal to reach reproductive age as soon as possible, given the problem of predators such as whales or large fish.
Whatever the biological reason for such a brief life, it is a melancholy fact.
. . .
What is it like to be an octopus? It’s not easy to say, but I speculate soft, malleable, brimming with sensation, vivid, expressive, exciting, complicated, tragic and determined. They make good, if brief, use of their portion of consciousness. They must live by the evolutionary laws that have created them, but there is an inner being that makes the best of its lot. Though it’s easy to think of octopuses as alien, a better view is that they are our cousins in biological destiny–spirits in a material world.

For the full review, see:
COLIN MCGINN. “Experiments in Intelligence.” The Wall Street Journal (Sat., December 3, 2016): C5-C6.
(Note: ellipses added.)
(Note: the online version of the review has the date Dec. 4 [sic], 2016, and has the title “Our Noble Cousin: The Octopus.”)

The book under review, is:
Godfrey-Smith, Peter. Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness. New York: Farrar, Straus and Giroux, 2016.

Rat Ticklers Find Ticklishness Has Deep Evolutionary Roots

(p. A12) As Michael Brecht and Shimpei Ishiyama of the Bernstein Center for Computational Neuroscience in Berlin point out in their report, tickling raises many questions. We don’t know why it evolved, what purpose it might serve and why only certain body parts are ticklish. And what about that disappointing and confounding truth that all children and scientists must grapple with: You can’t tickle yourself.
The researchers were also inspired by earlier studies. ” ‘Laughing’ Rats and the Evolutionary Antecedents of Human Joy?” published in 2003 in Physiology & Behavior, reported that rats would emit ultrasonic calls when tickled. Ultrasound is too high for humans to pick up.
. . .
The scientists found that tickling and play, which involved chasing a researcher’s hand, both caused the same ultrasonic calls and the same brain cells to be active. The scientists also stimulated those cells electrically, without any tickling or play, and got the same calls.
And they found that you can’t tickle rats when they are not in a good mood, something that is also true of people.
. . .
And the similarity of tickling in rats and humans is, Dr. Brecht said, “amazing.” They even have similar areas that are susceptible for unknown reasons, including the soles of their hind feet, but not of their forepaws.
That similarity suggests that tickling is evolutionarily very ancient, going back to the roots of touch as a way to form social bonds in the ancestors of rats and humans.
“Maybe,” Dr. Brecht speculated, “ticklishness is a trick of the brain to make animals or humans play or interact in a fun way.”

For the full story, see:

JAMES GORMAN. “When Tickled, Rats Giggle and Leap, Researchers Find.” The New York Times (Fri., NOV. 11, 2016): A12.
(Note: ellipses added.)
(Note: the online version of the story has the date NOV. 10, 2016, and has the title “Oh, for the Joy of a Tickled Rat.”)

Ishiyama and Becht’s recent report, discussed above, is:
Ishiyama, S., and M. Brecht. “Neural Correlates of Ticklishness in the Rat Somatosensory Cortex.” Science 354, no. 6313 (Nov. 11, 2016): 757-60.

The earlier paper mentioned above, is:
Panksepp, Jaak, and Jeff Burgdorf. “”Laughing” Rats and the Evolutionary Antecedents of Human Joy?” Physiology & Behavior 79, no. 3 (Aug. 2003): 533-47.

Another paper in this line of research, is:
Rygula, Rafal, Helena Pluta, and Piotr Popik. “Laughing Rats Are Optimistic.” PLoS ONE 7, no. 12 (Dec. 2012): 1-6.

Laws to Protect “Endangered” Species “Lag Far Behind Scientific Research”

(p. A19) The first large study of North American wolf genomes has found that there is only one species on the continent: the gray wolf. Two other purported species, the Eastern wolf and the red wolf, are mixes of gray wolf and coyote DNA, the scientists behind the study concluded.
The finding, announced Wednesday, highlights the shortcomings of laws intended to protect endangered species, as such laws lag far behind scientific research into the evolution of species.
The gray wolf and red wolf were listed as endangered in the lower 48 states under the Endangered Species Act in the 1970s and remain protected today, to the periodic consternation of ranchers and agricultural interests.

For the full story, see:
Zimmer, Carl. “The One and Only Wolf Species of North America.” The New York Times (Thurs., JULY 28, 2016): A19.
(Note: ellipses added.)
(Note: the online version of the commentary has the date JULY 27, 2016, and has the title “MATTER; DNA Study Reveals the One and Only Wolf Species in North America.”)

Life Discovered 220 Million Years Earlier than Previous Oldest

(p. A12) Geologists have discovered in Greenland evidence for ancient life in rocks that are 3.7 billion years old. The find, if confirmed, would make these fossils the oldest on Earth and may change scientific understanding of the origins of life.
. . .
The new fossils, described on Wednesday [August 31, 2016] in the journal Nature, are the first visible structures found in the Isua rocks. They are thought to be stromatolites, layers of sediment packed together by microbial communities living in shallow water.
They are some 220 million years more ancient than the oldest previously known fossils, also stromatolites. Those are 3.48 billion years old and were discovered in the Pilbara Craton of Western Australia.
The new report “provides the oldest direct evidence of microbial life,” said Gerald Joyce, an expert on the origin of life at the Scripps Research Institute in La Jolla, Calif.
. . .
If life on Earth did not begin until after the Late Heavy Bombardment, then it had a mere 100 million years in which to evolve to the quite advanced stage seen in the new fossils.
If so, Dr. Allwood wrote, then “life is not a fussy, reluctant and unlikely thing.” It will emerge whenever there’s an opportunity.

For the full story, see:
NICHOLAS WADE. “Greenland Fossils Could Be Oldest Ever Found.” The New York Times (Thurs., Sept. 1, 2016): A12.
(Note: ellipses, and bracketed date, added.)
(Note: the online version of the commentary has the date AUG. 31, 2016, and has the title “World’s Oldest Fossils Found in Greenland.”)

The article in Nature, mentioned above, is:

Nutman, Allen P., Vickie C. Bennett, Clark R. L. Friend, Martin J. Van Kranendonk, and Allan R. Chivas. “Rapid Emergence of Life Shown by Discovery of 3,700-Million-Year-Old Microbial Structures.” Nature (2016), DOI: 10.1038/nature19355.

Scientists Reviving Extinct Tortoise Species

(p. D1) . . . the story of extinct Galápagos tortoises has taken a strange, (p. D5) and hopeful, twist.
More than a century ago, it turns out, sailors dumped saddlebacked tortoises they did not need into Banks Bay, near Wolf Volcano on Isabela Island. Luckily, tortoises can extend their necks above water and float on their backs. Many of them made it to shore, lumbered across the lava fields and interbred with Isabela’s native domed tortoises.
In 2008, scientists tagged and collected blood samples from more than 1,600 tortoises living on the flanks of the volcano. Back in the laboratory, there was a genetic eureka: Eighty-nine of the animals were part Floreana, whose full genetic profile DNA had been obtained from museum samples.
Some had genes indicating their parents were living purebred Floreana tortoises, hinting that the species may not be extinct after all.
Seventeen tortoises were shown to have high levels of Pinta DNA. Tortoises can live for more than 150 years, so some of them may well be George’s immediate next of kin.
Last month, scientists went back to find them. Their plan was to capture and separate tortoises with high levels of Pinta and Floreana DNA, and then breed animals that are genetically closest to the original species.
In just a few generations, it should be possible to obtain tortoises with 95 percent of their “lost” ancestral genes, the scientists said.

For the full story, see:
SANDRA BLAKESLEE. “A Lost Species Crawls Back to Life.” The New York Times (Tues., DEC. 15, 2015): D1 & D5.
(Note: ellipsis added.)
(Note: the online version of the commentary has the date DEC. 14, 2015, and has the title “Scientists Hope to Bring a Galápagos Tortoise Species Back to Life.”)

Details of a Case of Gene Transfer Between Species

(p. A7) . . . in recent years, scientists have pinpointed many instances of horizontal gene transfer–genes being ferried from one species into an entirely unrelated species that happens to live in the same environment.
For example, a gene from a species of bacteria has been discovered in the genome of the coffee berry borer beetle, where it enables the beetle to feed exclusively on coffee beans. It is through horizontal gene transfer that bacteria typically develop antibiotic resistance.
A few months ago, a team of U.K. researchers concluded that the “jumping gene” method enabled humans to acquire more than 145 foreign genes from bacteria, viruses and fungi over the course of our evolution.
The big mystery is: How does this happen? In the latest study, researchers suggest a possible route whereby the genes of parasitic wasps jump into the genomes of butterflies and moths.

For the full story, see:
GAUTAM NAIK. “Scientists Find How Genes Jump Species.” The Wall Street Journal (Fri., Sept. 18, 2015): A7.
(Note: ellipsis added.)
(Note: the online version of the story has the date Sept. 17, 2016, and has the title “Scientists Learn How Genes Can Jump Between Species.”)

The academic paper reporting the possible details of a process of horizontal gene transfer, is:
Gasmi, Laila, Helene Boulain, Jeremy Gauthier, Aurelie Hua-Van, Karine Musset, Agata K. Jakubowska, Jean-Marc Aury, Anne-Nathalie Volkoff, Elisabeth Huguet, Salvador Herrero, and Jean-Michel Drezen. “Recurrent Domestication by Lepidoptera of Genes from Their Parasites Mediated by Bracoviruses.” PLoS Genetics 11, no. 9 (Sept. 17, 2015): e1005470.

The Roles of Bad Luck and Periodicity in Species Extinctions

To the extent that bad luck, and periodically recurring natural causes, explain species extinctions, the role of humans in causing extinctions may be less than is sometimes assumed.

(p. A21) Dr. Raup challenged the conventional view that changes in diversity within major groups of creatures were continuous and protracted, and advanced the theory that such changes can be effected by random events.

And he questioned the accepted notion that biodiversity — that is, the number of extant species — has vastly increased over the past 500 million years, pointing out, among other things, that because newer fossils embedded in newer rock are easier to find than older fossils in older rock, it is possible that we simply have not uncovered the evidence of many older species whose existence would undermine the theory. His conclusion, that the data of the fossil record does not allow the unambiguous presumption that biodiversity has increased, has profound implications.
. . .
Dr. Raup’s most famous contribution to the field may have been the revelation in 1983, after a six-year study of marine organisms he conducted with J. John Sepkoski Jr., that over the last 250 million years, extinctions of species spiked at regular intervals of about 26 million years.
Extinction periodicity, as it is known, enlivened the study of huge volcanic eruptions and of changes in the earth’s magnetic field that may have coincided with periods of mass extinction. It has also given rise to numerous theories regarding the history of life, including that the evolution of myriad species has been interrupted by nonterrestrial agents from the solar system or the galaxy.
. . .
“Much of our good feeling about planet Earth stems from a certainty that life has existed without interruption for three and a half billion years,” he wrote. “We have been taught, as well, that most changes in the natural world are slow and gradual. Species evolve in tiny steps over eons; erosion and weathering change our landscape but at an almost immeasurably slow pace.”
He continued: “Is all this true or merely a fairy tale to comfort us? Is there more to it? I think there is. Almost all species in the past failed. If they died out gradually and quietly and if they deserved to die because of some inferiority, then our good feelings about earth can remain intact. But if they died violently and without having done anything wrong, then our planet may not be such a safe place.”

For the full obituary, see:
BRUCE WEBER. “David M. Raup, Who Transformed Field of Paleontology, Dies at 82.” The New York Times (Thurs., JULY 16, 2015): A21.
(Note: ellipses added.)
(Note: the online version of the obituary has the date JULY 15, 2015 and has the title “David M. Raup, Who Transformed Field of Paleontology, Dies at 82.”)

Some “Rescue” Groups “Kidnap and Mutilate” Street Dogs

(p. D1) MONTAGUE, Mass. — Think of all the dogs out there: labradors and poodles and labradoodles; huskies and westies and dogues de Bordeaux; pit bulls and spaniels and lovable mutts that go to doggy day care.
Add them up, all the pet dogs on the planet, and you get about 250 million.
But there are about a billion dogs on Earth, according to some estimates. The other 750 million don’t have flea collars. And they certainly don’t have humans who take them for walks and pick up their feces. They are called village dogs, street dogs and free-breeding dogs, among other things, and they haunt the garbage dumps and neighborhoods of most of the world.
In their new book, “What Is a Dog?,” Raymond and Lorna Coppinger argue that if you really want to understand the nature of dogs, you need to know these other animals. The vast majority are not strays or lost pets, the Coppingers say, but rather superbly adapted scavengers — the closest living things to the dogs that first emerged thousands of years ago.
. . .
(p. D6) In 2001, their book “Dogs: A Startling New Understanding of Canine Origin, Behavior & Evolution” challenged the way scientists thought about the beginnings of dogs.
They argued against the widely held view that one day a hunter-gatherer grabbed a wolf pup from a den and started a breeding program. Instead, they argued, dogs domesticated themselves.
Some wild canines started hanging around humans for their leftovers and gradually evolved into scavengers dependent on humans. Not everyone in canine science shares that view today, but many researchers think it is the most plausible route to domestication.
. . .
Although the Coppingers recognize the social cost of animals that are unvaccinated and running free, they argue that killing the dogs, as some countries do during rabies epidemics, does not help. It’s impossible to kill them all, and because they breed rapidly, the population quickly rebounds.
Nor do the Coppingers have any sympathy for rescue groups that, as Dr. Coppinger puts it, “kidnap and mutilate” street dogs from the Caribbean and elsewhere to bring them to American shelters to live as pets, “where they are made totally dependent and entirely restricted.” This is supposed to benefit the dogs, but Dr. Coppinger argues that they are taken from a rich social environment, with many dogs, to lives of relative isolation.

For the full story, see:
JAMES GORMAN. “Don’t Call them Strays.” The New York Times (Tues., APRIL 19, 2016): D1 & D6.
(Note: the online version of the story has the date APRIL 18, 2016, and has the title “The World Is Full of Dogs Without Collars.”)

The dog books mentioned above, are:
Coppinger, Raymond, and Lorna Coppinger. What Is a Dog? Chicago: University of Chicago Press, 2016.
Coppinger, Raymond, and Lorna Coppinger. Dogs: A Startling New Understanding of Canine Origin, Behavior & Evolution. New York: Scribner, 2001.