Chemistry of Love: Owl Monkeys Shed Light on Evolution of Love - [Article]

(National Geographic, 13, Feb 2013) - It may not seem like monkey business, but emotional bonds in animals such as primates may have evolved into love as we know it.

Journal article: Till Death (Or an Intruder) Do Us Part:Intrasexual-Competition in a Monogamous Primate

Take owl monkeys, tiny tropical tree-dwellers that treat every day like it's Valentine's Day. A male and a female stick together as long as possible, never cheat, and never "divorce" their mates—extremely unusual behavior, even among people. (Also see "Male Monkeys Wash With Urine to Attract Females?")

Sometimes, though, young adult owl monkeys that can't find mates—monkeys that scientists call floaters—pick vicious fights with established pairs, eventually kicking one of them out.

Now, new research shows that the monkeys forced to take on new partners have fewer babies than owl monkeys that haven't been broken up, said Eduardo Fernandez-Duque, a biological anthropologist at the University of Pennsylvania in Philadelphia who led a new study on owl monkey relationships.

The results show how monogamy helps owl monkeys—and may even shed light on how human relationships evolved, said Fernandez-Duque, who has received funding for his work from National Geographic's Committee for Research and Exploration. (National Geographic News is part of the National Geographic Society.)

"Call it love, call it friendship, call it marriage—there is something in our biology that leads to this enduring, emotional bond between two individuals that is widespread among human societies," Fernandez-Duque said in a statement.

Only about 5 percent of mammals are monogamous, and the phenomenon most often arises when both parents are needed to raise offspring, as in the case of people.

With owl monkeys, fathers take on most of the childcare after a baby is born, relying on the mother only for milk. (See video: "Owl Monkey Fathers Know Best?")

But floaters—which Fernandez-Duque and colleagues first noticed in 2003 in Argentina's Chaco region (map)—can spell trouble in paradise.

Drawing on nearly two decades of observations of 18 owl monkey groups, the team discovered that pairs that stay intact produce 25 percent more babies than monkeys in severed pairs.

The exiled animal from those broken relationships, meanwhile, is usually injured and often dies.

Since the team studied more than 150 animals, "I felt very confident that what he was telling us is a real phenomenon—it's not a flash in the pan," noted Patricia Wright, who was one of the first people to study owl monkeys in the 1980s.

"He had the goods on the animals. I was really excited about that," said Wright, an anthropologist at Stony Brook University in New York.

Wright said she was personally pleased that the study reinforced findings that owl monkeys stay true to one another unless forced to separate.

"I knew that these little monkeys didn't fool around," she said.

Why monkeys that are broken up have fewer babies is unknown, though Fernandez-Duque suspects there's an emotional component. (See more pictures of all-star animal dads.)

Just as a man and a woman need time to get to know each other and form a deep connection, so do owl monkeys. So when a marauding monkey enters into a new relationship, there's a delay in mating—usually about a year, Fernandez-Duque  said.

In fact, pair bonding in monogamous animals, such as owl monkeys, may be "sort of evolutionary antecedent to love in humans," said Larry Young, a behavioral neuroscientist at Emory University in Atlanta and author of the new book The Chemistry Between Us: Love, Sex, and the Science of Attraction.

Young, who studies the brain chemistry of love and emotion, does most of his research on monogamous prairie voles.

Though human love is a rich emotion reflective of our advanced brains, he said, "the foundation of that emotion is very similar to the neuromechanisms that are causing the bond between these two prairie voles."

For instance, experiments have shown that if a vole loses its partner, the "widowed" animal shows depressive symptoms—measured by a lack of willingness to escape a dangerous situation.

According to Young, our brains are in the love seat, so to speak: The organs "have evolved the mechanism to produce an emotional attachment," he said.

That attachment is spurred by oxytocin—produced during intimate contact in both people and animals—and dopamine, which is responsible for feelings of exhilaration and happiness.

So, many splendored as it is, love, he said, "is really the result of a cocktail of chemicals."

Evolution Doesn't Always Mean The Most Badass - [Comic]

Size Does Matter. Brain Size!

Big brains, but all they
want to talk about is mackerel. 

(Discover Magazine, Sept, 11, 2012) - Every whale and dolphin evolved from a deer-like animal with slender, hoofed legs, which lived between 53 and 56 million years ago. 

Over time, these ancestral creatures became more streamlined, and their tails widened into flukes. They lost their hind limbs, and their front ones became paddles. And they became smarter.  Today, whales and dolphins – collectively known as cetaceans – are among the most intelligent of mammals, with smarts that rival our own primate relatives.

Now, Shixia Xu from Nanjing Normal University has found that a gene called ASPM seems to have played an important role in the evolution of cetacean brains. The gene shows clear signatures of adaptive change at two points in history, when the brains of some cetaceans ballooned in size. But ASPM has also been linked to the evolution of bigger brains in another branch of the mammal family tree – ours. It went through similar bursts of accelerated evolution in the great apes, and especially in our own ancestors after they split away from chimpanzees.

It seems that both primates and cetaceans—the intellectual heavyweights of the animal world—could owe our bulging brains to changes in the same gene. “It’s a significant result,” says Michael McGowen, who studies the genetic evolution of whales at Wayne State University. “The work on ASPM shows clear evidence of adaptive evolution, and adds to the growing evidence of convergence between primates and cetaceans from a molecular perspective.”

For decades, we’ve known that similarities between primate and cetacean intelligence run deep. For a start, both groups have members with unusually big brains. We humans have brains that are 7 times bigger than you’d expect for an animal of their size. The equivalent number is 2-3 for chimps and some monkeys, and 4-5 for some dolphins.

Over the last decade, scientists have identified seven genes that are linked to primate brain size. They’re called MCPH1 to MCPH7 (ASPM is the fifth in the line). Faults in these genes can lead to microcephaly – a developmental disorder characterised by a debilitatingly small brain.

McGowen had already shown that, unlike in humans, MCPH1 doesn’t neatly correlate with brain size in cetaceans. Xu wanted to see if ASPM would be more interesting. He sequenced the gene in fourteen species of cetaceans, from the bottlenose dolphin to the minke whale. He then compared these to known sequences from 18 other mammals, including several primates and the hippopotamus (the closest living relative to cetaceans).

Xu found that ASPM went through two periods of strong positive selection – where beneficial new versions of the gene spread through a population. The first coincides with the point when toothed whales (like sperm whale and dolphins) split away from the baleen whales (like blue, fin and humpback whales). Their brains got bigger. The second period marks the split of the toothed whales into the delphinoids (including all oceanic dolphins and porpoises) and all the others. The delphinoids’ already big brains got bigger still.

Xu also found signatures of positive selection within the ASPM genes of primates, but not in any other mammal groups. During their history, both groups must have experienced some evolutionary pressures that meant bigger brains suddenly became advantageous. We can only speculate what these might have been. For cetaceans, the toothed whales evolved to navigate with echolocation, and may have needed a larger brain to process the information from all the returning echoes. The delphinoids may owe their larger brains to the mental demands of living in large, complex social groups. (Both hypotheses have been on the cards for some time, and Xu’s ASPM discovery doesn’t provide a smoking gun for either.)

What does ASPM actually do? The gene is activated in neuroblasts, the embryonic cells that eventually divide into neurons. It helps to create structures in dividing cells that send a full complement of DNA into each daughter. If ASPM isn’t working properly, the neuroblasts cannot divide evenly, and brains get smaller. It’s not clear how the reverse happens – how changes in ASPM lead to bigger brains, but it’s now clear that this has happened in at least two mammal groups.

Xu found certain mutations that were associated with the bigger brains of toothed whales, and others that are associated with the even bigger brains of delphinoids. What these mutations did is anyone’s guess, and something that will take a lot of experimental work to uncover.

Here’s one critical nugget, though: they’re different to the changes you see in primates. The same gene may have enlarged the brains of both groups, but it did so in different ways. And undoubtedly, other genes were also involved.

(To close, here’s possibly my favourite ever example of convergent evolution, which also involves cetaceans. Toothed whales and some bats both use echolocation, and their abilities depend on the same changes to the same gene – Prestin. This was discovered at the same time by two independent groups of researchers, one led by Yang Liu and the other by Ying Li!)

Reference: Xu, Chen, Cheng, Yang, Zhou, Xu, Zhou & Yang. 2012. Positive selection at ASPM gene coincides with brain size enlargements in cetaceans. Proc Roy Soc B.

Evolutionary Comparison Finds Shocking History for Vertebrates

 !!0_0!!

Wired UK (Oct, 12. 2011) - Evolutionary biologists from Cornell University have discovered that just about every vertebrate on Earth — including humans — descended from an ancient ancestor with a sixth sense: the ability to detect electrical fields in water.

About 500 million years ago there was probably a predatory marine fish with good eyesight, powerful jaws and sharp teeth roaming the oceans, sporting a lateral line system for detecting water movements and a well-developed electroreceptive system to sense predators and prey around it. The vast majority of the 65,000 or so living vertebrate species are its descendants.

A few hundred million years ago, there was a major fork in the evolutionary tree. One lineage led to the ray-finned fishes, or actinopterygians, and they’ve kept a weak electroreceptive system to this day. Sturgeon have receptors in the skin of their heads, for example, and the North American paddlefish has 70,000 receptors in its snout and head.

The other lineage led to lobe-finned fishes, or sarcopterygians, which in turn gave rise to land vertebrates. Some land vertebrates, including salamanders like the Mexican axolotl, still have electroreception. But in the change to terrestrial life, the lineage leading to reptiles, birds and mammals lost that electrosense and the lateral line.

The researchers took the axolotl (to represent the evolutionary lineage leading to land animals) and the paddlefish (as a model for the branch leading to ray-finned fishes) to find out the history of this sense. They found that electrosensors develop in precisely the same pattern from the same embryonic tissue in the developing skin, confirming that this is an ancient sensory system.

Also, the electrosensory organs develop immediately adjacent to the lateral line, providing compelling evidence “that these two sensory systems share a common evolutionary heritage,” said Willy Bemis, Cornell professor of ecology and evolutionary biology and a senior author of the paper.

Bemis and his colleagues will now be able to build a better picture of what the common ancestor of these two lineages looked like.

Richard Dawkins Interview

An interview with the evolutionary biologist, best-selling author and outspoken atheist.

'Once in a lifetime' rare white whale calf spotted off Australia

The Telegraph.co.uk (Sept. 29, 2011) - An extremely rare white humpback whale calf has been spotted near Australia's Great Barrier Reef in an event witnesses described Thursday as a "once in a lifetime experience".

Believed to be just a few weeks old, the baby humpback was seen at Cid Harbour in the famous reef's Whitsunday Islands area by local man Wayne Fewings, who was with his family in a boat when he spotted a whale pod.

"We were just drifting when I noticed the smaller whale in the pod was white. I couldn't believe my eyes, and I just grabbed my camera," Fewings said.

"Then the white calf approached my boat, seeming to want to check us out. I was just so amazed at seeing this animal, it made me think how truly astounding the Great Barrier Reef is," he added of the sighting on Saturday.

"I feel very lucky to have witnessed this, it's a once in a lifetime experience."

Reef official Mark Read said white whales were highly unusual, with only 10-15 believed to exist among the 10,000-15,000 humpbacks living along Australia's east coast, and purely white ones – like the calf spotted on Saturday – rarer still.

Its parents could both have been dark humpbacks carrying the recessive white whale gene, but Read said one or either may also have been white themselves, raising speculation it was the offspring of famous white humpback Migaloo.

Migaloo – the name is an Aboriginal word meaning "whitefella" – is the world's best-known all-white humpback and has built up a loyal following in Australia since first being sighted in 1991.

Humpback whales are currently on their southern migration and Mr Read said the baby white would be feeding heavily from its mother as it laid down fat stores for the "cold Antarctic waters."

Its sex was unknown and Read said there were no plans to bestow the young mammal with a name of its own.

"We'd be pretty comfortable for him or her just to simply remain anonymous and just live out its life in relative peace and harmony," Read said.

Australia's east coast humpback population has been brought back from the brink of extinction following the halting of whaling in the early 1960s, he added, describing it as a "conservation success story."

Sexy snacks: Study finds female mate searching evolves when mating gifts are important

PHYSORG.com (Sept. 28, 2011) - In the animal world, males typically search for their female partners. The mystery is that in some species, you get a reversal -- the females search for males.

A new study of katydids in the latest issue of the journal Proceedings of the Royal Society B -- co-authored by U of T Mississauga professor Darryl Gwynne -- supports a theory that females will search if males offer a lot more than just sperm.

"In this beast [in this study], it's a big cheesy, gooey substance that the male ejects when he copulates," says Gwynne. "It's attached to his sperm packet, so while she's being inseminated, she can reach back and grab this mating gift and eat it."

Gwynne met the lead author of the study, Jay McCartney, while on sabbatical at Massey University in New Zealand. Since part of his own research expertise covered the mating behaviours of these types of insects, Gwynne was asked to act as a co-supervisor of the project and suggested that the data could provide clues into the diversity in nature of how animals search for mates.

"Males mostly do the searching, because the Darwinian sexual selection process is typical stronger in males; they're competitive," says Gwynne." As a consequence of their eagerness to get to the females, the females just hang out waiting for the males to come to them."

In the insects that Gwynne works with, some males sing to advertise that they have a safe burrow to offer the females, while in other species, they offer the females a nutritional perk. In the katydids, where a female searched for a male, she stood to gain the largest nutritional gift.

And from the male's perspective, a large food gift not only potentially benefits his offspring, but distracts the female long enough to ensure that he has time for a full insemination. Otherwise, says Gwynne, "she's hungry…if he didn't give her this gift, she'd just pull off the sperm packet and snack on that like a little hors d'oeuvre." Gwynne says that female searching behaviour exists elsewhere in the animal kingdom -- for example, in singing animals like frogs -- and deserves further study.

Mother Tongue Comes from Your Prehistoric Father

ScienceDaily (Sep. 17, 2011) — Language change among our prehistoric ancestors came about via the arrival of immigrant men -- rather than women -- into new settlements, according to new research.

The claim is made by two University of Cambridge academics, Peter Forster and Colin Renfrew, in a report to be published in Science on September 9.

They studied the instances of genetic markers (the male Y chromosome and female mtDNA) from several thousand individuals in communities around the world that seem to show the emergence globally of sex-specific transmission of language.

From Scandinavian Vikings who ferried kidnapped British women to Iceland -- to African, Indian and Polynesian tribes, a pattern has emerged which appears to show that the arrival of men to particular geographic locations -- through either agricultural dispersal or the arrival of military forces -- can have a significant impact on what language is spoken there.

Professor Renfrew said: "It may be that during colonisation episodes by emigrating agriculturalists, men generally outnumber women in the pioneering groups and take wives from the local community.

"When the parents have different linguistic backgrounds, it may often be the language of the father which is dominant within the family group."

Dr Forster, of Murray Edwards College, also pointed to the fact that men have a greater variance in offspring than women -- they are more likely to father children with different mothers than vice versa. This has been recorded both in prehistoric tribes such as the 19th and 20th century Polar Eskimos from Greenland and in historic figures like Genghis Khan, who is believed to have fathered hundreds of children.

Indeed, his Y chromosome is carried by 0.5 per cent of the world's male population today.

Perhaps the most striking example of sex-biased language change however comes from a genetic study on the prehistoric encounter of expanding Polynesians with resident Melanesians in New Guinea and the neighbouring Admiralty Islands. The New Guinean coast contains pockets of Polynesian-speaking areas separated by Melanesian areas. The Polynesian mtDNA level (40-50%) is similar in these areas regardless of language, whereas the Y chromosome correlates strongly with the presence of Polynesian languages.

Past studies have shown similar findings in the Indian subcontinent among the speakers of Tibeto-Burman and among the immigrant Indo-European languages as opposed to indigenous Dravidian languages.

In the Americas, too, language replacement in the course of postulated farming dispersal has also been found to correlate for the Uto-Aztecan language family.

Added Forster: "Whether in European, Indian, Chinese or other languages, the expression 'mother tongue' and its concept is firmly embedded in popular imagination -- perhaps this is the reason why for so many years the role of fathers, or more likely, specific groups of successful males, in determining prehistoric language switches has not been recognised by geneticists."

"Prehistoric women may have more readily adopted the language of immigrant males, particularly if these newcomers brought with them military prowess or a perceived higher status associated with farming or metalworking."

Journal Reference:
P. Forster, C. Renfrew. Mother Tongue and Y Chromosomes. Science, 2011; 333 (6048): 1390 DOI:10.1126/science.1205331

A Discovery Could Help Date Monkey-Ape Split

***TESTER BLOG***

There are a few important differences between Old World monkeys and apes. Old World monkeys, like baboons and macaques, have tails and a great deal of agility, enabling them to jump and swing from tree branches.

Apes, which include gorillas and chimpanzees, are tail-less and tend to have a more upright posture. Scientists agree that Old World monkeys and apes share a common ancestry, but at some point two lineages diverged, one giving rise to the Old World monkeys and another to both apes and humans. Exactly when the split happened is a matter of debate.

A primate skull unearthed outside of Mecca in Saudi Arabia is the closest common ancestor to apes and Old World monkeys, researchers say, and helps date the split. Sediment records indicate that the fossil is 25 million to 29 million years old, making 24 million to 29 million years ago the window in which the monkey-ape split may have occurred. The ape and human lineages split later.

The research appears in the journal Nature.  

“It is neither a monkey, nor an ape,” said Iyad Zalmout a palaeontologist at the University of Michigan and the study’s lead author. “You have an intermediate primate that tells you a story about Old World monkeys and apes.”

Based on the skull, the primate was medium-sized and weighed about 30 pounds to 40 pounds. It had broad upper molars and a long, baboon like snout.  

A previous estimate, made with DNA samples of living primates found that the split occurred earlier, 34.5 million to 29.2 million years ago. There is however, no fossil evidence to support this.

***TESTER BLOG***