Review: Darwin’s Unfinished Symphony by Kevin N. Layland

darwin symphonyA version of this review appeared in Issue 75 of Cosmos Magazine, July 2017 

The runaway evolution that drove human brilliance

Darwin’s Unfinished Symphony: How Culture Made the Human Mind
by KEVIN N. LALAND
Princeton University Press (2017)

Evolutionary biologists are often loath to admit the vast gap that exists between our own brilliance and the relatively modest smarts of our animal brethren. Tracing an evolutionary sequence of incremental changes in body shape from apes to humans is reasonably simple. Charting changes in intellect presents more of a challenge. Humans alone have built particle accelerators, propelled astronauts into space, and manipulated the genetic code of other organisms. No other animal even comes close.

In Darwin’s Unfinished Symphony, Kevin Laland not only admits that a seemingly insurmountable gap exists, he takes up the challenge of explaining how a step-wise process of natural selection – as it was first explored by Darwin in his Descent of Man (1871) – can be used to explain what sets the human mind so dramatically apart.

Laland draws on more than two decades of work in his own lab, as well as work by other animal behaviourists and evolutionary biologists, to argue that culture has colluded with genetics to catapult humans far ahead of other animals on the intelligence league board. His elegant theory also positions the human mind as an architect in its own evolution.

Laland traces human intelligence back to its elemental components. Conveniently, many of these components, such as the abilities to imitate, innovate, teach and communicate, have been rigorously interrogated in a staggering array of species, from honeybees to crows, stickleback fish to chimpanzees, dolphins to meerkats.

In recent decades, it has become clear that none of these skills is entirely unique to humans. Chimpanzees use tools to solve puzzles, meerkats teach their young how to kill scorpions, whales bellow out songs in regional dialects. But only in humans do these components come as a package deal. And all promote the evolution of large brains and greater intelligence.

Once our ancestors became reliant on two of these foundational elements – the ability to innovate, and the ability to accurately copy the behaviours of more learned members of our social group – a path towards culture was set. Innovation brought things like stone tools, which became entrenched in our culture thanks to our ability to copy, teach and communicate with each other.

As each of these cognitive skills was honed, more cultural practices were added to our repertoire and retained from one generation to the next. The cultural practices in turn cemented the mental abilities we needed in order for culture to thrive and become more complex. Rather than being a simple outgrowth of human mental abilities, says Laland, culture is part of the explanation for those mental abilities.

Culture also influenced traits not related to our brain. For example, when Northern Europeans began dairy farming, a rare gene variant that allowed adults to digest lactose, the sugar in milk, rapidly spread through the population, and remains common in dairy-consuming cultures today.

This intimate feedback between our genes and our culture created a runaway process, and the speed of human evolution, particularly of the mind, ratcheted up in response. Laland’s account provides a satisfying – if at times laborious – explanation for the origins of intelligence and culture that extends beyond our own existence to that of other animals, our prehistoric forebears, and our hunter-gatherer contemporaries.

The next generation of weapons against antibiotic-resistant superbugs

From Cosmos Magazine, June 30, 2017 (Image: naturalismus via Flickr) 

At his North Adelaide practice, Peter-John Wormald has the unenviable job of unblocking the noses of people with chronic sinusitis. Many of his patients have spent years on antibiotics that have failed to budge their infection, providing the perfect breeding ground for resistant superbugs.

For four out of five of them, surgery is the answer. Wormald carves away inflamed tissue, widens sinus openings and flushes out accumulated pus. For the stubborn one in five, however, Wormald is conducting one of the world’s first clinical trials into phage therapy, a century-old idea that predates modern antibiotics.

Such trials are desperately needed. We are on the threshold of returning to the dark ages that preceded antibiotics. Read more… 

Killer whale menopause evolved from mother-daughter conflict

Killer whale Shawn McCready.jpg

From Cosmos Magazine, January 13, 2017 (Image: Shawn McCready via Flickr)

Menopause is an evolutionary anomaly. Only in three species – humans, orcas and short-finned pilot whales – does female reproduction grind to a halt part-way through life.

For orcas (Orcinus orca), a new study published in Current Biology shows that menopause isn’t just a quirk of nature, but a reproductive strategy that specifically evolved to match their social structure. Read more…

Tails gave early land animals a leg up

From Cosmos Magazine, July 8, 2016. (Image: Klaus Stiefel via Flickr)

The muscular tails that propelled prehistoric fish through water may have been essential for their move onto land, a study in Science reports.

The transition from life in Earth’s watery depths to life on land occurred roughly 385–360 million years ago. All modern four-limbed land animals – “tetrapods” including mammals, birds, reptiles and amphibians – can trace their lineage back to pioneering land dwellers from this time.

But how aquatic animals moved about on land has been a matter of speculation. Until now, palaeontologists have largely relied on fossils and track marks to make their predictions. Read more…

Jawbone and teeth reveal hobbit’s 700,000-year-old ancestors

From Cosmos Magazine, June 9, 2016. (Photo by Kinez Riza)

A jawbone and six teeth push back the origins of the “hobbit” – a tiny species of early human – by more than half a million years.

Two studies, published in Nature, detail the remarkable find.

They suggest that the hobbit’s ancestors were already dwarfed and living on the Indonesian island of Flores 700,000 years ago. Read more…

Where did we come from? A primer on early human evolution

From Cosmos Magazine, June 9, 2016. Homo floresiensis photo by Karen Neoh via Flickr

The story of human origins is a messy one. Each bone fragment that’s unearthed or ancient genome that’s decoded adds a new piece to the puzzle – and it doesn’t necessarily make the picture any clearer.

“Human evolution is not a line of cartoons from a bent-over chimpanzee to a modern human,” says Fred Spoor, a palaeoanthropologist from University College, London. “It’s a complex business.”

While Spoor and his colleagues revel in the increasingly bushy family tree that is emerging, the rest of us can be left up the proverbial tree.

So, here’s what we do – and don’t – know about where we came from. Read more…

How the fruit fly got its stink

Dmelanogaster
Drosophila melanogaster (photo credit: André Karwath via Flickr)

Male fruit flies dampen the libido of sexual rivals with smelly pheromone.

The struggle to reproduce and leave behind a genetic legacy has seen the evolution of a variety of weird and wonderful mating features. While male birds such as the peacock don fancy feathers and conduct elaborate courtship dances to outcompete rivals, male fruit flies employ a far less savoury tactic.

For the fruit fly Drosophila melanogaster, the tiny workhorse of the genetics lab, mating isn’t a guarantee of reproductive success. A male who has successfully mated with a female could still be outdone if a rival comes along and mates with his partner after he has wandered off in post-coital bliss. Sperm from both males will compete for the ultimate prize of fertilising the female’s egg.
One way that male fruit flies try to keep their sexual conquests to themselves is by offering their lover a smelly pheromone perfume as a parting gift to repel further would-be suitors.

How this intriguing system evolved is the subject of study published this week in the Proceedings of the National Academy of Sciences, USA. Continue reading “How the fruit fly got its stink”