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One hundred years ago, on 28 November 1924, anthropologist Raymond Dart opened a crate. It held a consignment of fossils from Taung, a quarry in South Africa, including a small skull that looked part-ape, part-human. Dart named it 鈥溾��. It was the first Australopithecus specimen to be identified, and the first evidence that early humans evolved in Africa 鈥� instead of Eurasia as was widely assumed at the time. The importance of the 鈥淭aung Child鈥�, as it鈥檚 known, is crystal clear.
Half a century later, Donald Johanson and his colleagues were excavating in the Afar region of Ethiopia. They found a partial skeleton on 24 November 1974 鈥� almost 50 years to the day after Dart opened his crate. During the subsequent celebrations, they played the Beatles song Lucy in the Sky with Diamonds, and expedition member Pamela Alderman suggested calling the skeleton 鈥淟ucy鈥�.
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Later, this ancient human also got a scientific name: Australopithecus afarensis. But the name 鈥�Lucy鈥� stuck and became part of pop culture, in a way that 鈥渢he Taung Child鈥� hadn鈥檛. Nowadays it is the done thing to assign names to significant hominin specimens: hence we have the famous fossils known as Neo, Selam and Denny.
(Incidentally it has also been 20 years since describing another ancient human species, the 鈥渉obbits鈥�, Homo floresiensis, from Flores in Indonesia. However, , so I鈥檓 not counting it as a major anniversary. Likewise, the species Homo habilis was , 60 years ago, but the remains were found several years earlier.)
So, what made Lucy such a big deal?
Lucy is one of those stories that I have heard a few times too often. I was born in the early 1980s, some years after the discovery. When I became interested in human evolution, Lucy鈥檚 discovery was an established myth, endlessly told and retold.
As a result, my relationship to Lucy is a bit like my relationship to the Beatles: they belong to my parents鈥� generation. The band鈥檚 music is so influential, so widely copied, that it takes a hefty imagination to understand what it must have been like to experience it as brand new: to hear that dramatic suspended chord at the start of A Hard Day鈥檚 Night or the dissonant wails of Tomorrow Never Knows, and know that you鈥檒l never listen to music quite the same way again.
On a side note: some years ago, when I was a staff writer for New 杏吧原创 and working in the London office, a group of us who were interested in human evolution discussed our favourite species. I realise now that we all picked groups that had been discovered in the 21st century: the hobbits, Australopithecus sediba and (my pick) the Denisovans. Those were the ones that 鈥渂elonged鈥� to our generation.
Anyhow, when it comes to human evolution, Lucy is now part of the furniture. But in 1974 she was a novelty.
Lucy is held up as an amazing single find. And she is: the skeleton is about 40 per cent complete, including bits of the skull, ribcage, arms and legs. Having this many bones from a single individual reveals things you couldn鈥檛 see if you had the same number of bones, but from several dozen individuals.
鈥淵ou can look at body proportions,鈥� says at the University of Missouri. By studying the relative lengths of Lucy鈥檚 limbs, and other details, we can see that she walked bipedally. 鈥淪he was just as good as you or I walking across the savannah.鈥� Likewise, from her teeth and other clues, we can get a sense of her diet 鈥� which was plant-heavy.
And so we started to paint a picture of a species based on this one specimen. The thing is, Lucy is not a typical A. afarensis.
Today we have more fossils of A. afarensis than of most other hominins. 鈥淟ucy stands out as the smallest,鈥� says at the University of California, Berkeley. 鈥淚f you played the tape again and only Lucy were found, you鈥檇 have a fundamentally misleading image of what afarensis is.鈥� He says it would be like if aliens abducted a human at random and got diminutive 1970s gymnast Olga Korbut, then tried to estimate our average height.
鈥淎ny time we find a fossil, we can鈥檛 assume that this is going to be the absolute average individual,鈥� says Ward.
However, was found, Johanson鈥檚 team made an equally seismic discovery at a nearby site: over 200 hominin bones belonging to at least 13 individuals. , like Lucy, and date from the same time: 3.2 million years ago. Technically known as 鈥淎.L. 333鈥� (meaning, fossil number 333 from the Afar Locality), they are nicknamed the 鈥溾��.
鈥淭丑补迟 afarensis sample is the gold standard for all early hominids until Neanderthals,鈥� says Ward. Because so many individuals are preserved, 鈥渨e actually have a window into variation in one species in the past鈥�.
This makes it easier to decide if a new specimen represents a new species or is just another A. afarensis. 鈥淲e have young and old individuals, we can say something about growth,鈥� says Ward. 鈥淲e have males and females, you can talk about dimorphism and social behaviour.鈥�
The fact so many individuals were found together implies that A. afarensis lived in groups, says , who is now at Arizona State University. 鈥淢ales and females lived together with offspring,鈥� he says. 鈥淭丑补迟, to me, was quite remarkable.鈥� In contrast, he points out, the Taung Child from 50 years earlier was found in isolation.
Lucy is best understood as part of the broader collection of A. afarensis fossils from that time period. Taken as a set, these bones paint a picture of a population of hominins roaming the Ethiopian landscape. They show us A. afarensis, not as a single data point on the line between apes and humans, but as living, breathing hominins that walked around and ate and had babies. Lucy may have personalised extinct hominins for the first time, but the First Family diversified them.
For White, the biggest discoveries in palaeoanthropology have been the ones where lots of individuals are found together. A.L. 333 is one such example. He also cites , which has yielded Ardipithecus, Australopithecus and Homo remains; Dmanisi in Georgia, with its Homo erectus remains that told us a lot about the first hominin to live outside Africa; and Sima de los Huesos in northern Spain, which holds the remains of early Neanderthals.
What unites these sites, argues White, is that they allow you to study a species in something approximating its full richness, rather than simply how it differs from another species.
Ward offers another perspective on the importance of spectacular fossils like Lucy. 鈥淏ig finds are truly remarkable,鈥� she says. 鈥淲hat they do is, they don鈥檛 answer the questions: they bring up the new questions.鈥� When Johanson and his team found Lucy, by extension they also found her entire species 鈥� and that raised all sorts of questions that could only be answered by more A. afarensis fossils.
鈥淭he hard part of science is not answering questions,鈥� says Ward. 鈥淚t鈥檚 knowing which questions to ask, because if you don鈥檛 ask the right questions, you鈥檒l never get the right answers.鈥� The lasting importance of Lucy, and the Taung Child for that matter, is that they prompted people to ask new questions. I never want to hear the story about the song ever again, but so long as Lucy keeps triggering new ideas and questions, she鈥檒l continue to be important.
