The earliest astronomers?

Reaching for the stars in Lascaux Cave
Standard

This post was chosen as an Editor's Selection for ResearchBlogging.orgThe short ver­sion of this post is that Astronomy in the Upper Palaeolithic? by Hayden & Villeneuve is a great paper. If you’re inter­ested in astro­nomy in hunter-gatherer soci­et­ies you should read it. I’m going to dis­agree with some parts of the paper below, but if Hayden & Villeneuve are wrong about some things, then it’s for inter­est­ing reas­ons. And it’s by no means cer­tain that I’m right to dis­agree about the things that I do.

Reaching for the stars in Lascaux Cave

Reaching for the stars in Lascaux Cave. Photo (cc) tourisme_vezere.

The archae­ology of astro­nomy is con­ten­tious at the best of times, but the Palaeolithic is a par­tic­u­larly dif­fi­cult period to study, because the remains are so frag­ment­ary and few in num­ber. So to put this in con­text we need to know when the Upper Palaeolithic is.

You’re prob­ably famil­iar with the Three Age System, Stone, Bronze and Iron Ages. In this sys­tem in Europe the Stone Age ends roughly between 4000 and 2500 BCE depend­ing on where you are and exactly where you want to draw the line. Everything before this is a long time period so you can split it up fur­ther. The Neolithic is a period when people settle down and become farm­ers, it starts between 8000 and 4000 BCE in Europe depend­ing on where you are. The south-east of Europe adopts farm­ing much sooner than the people in the north-west. The Palaeolithic, if you ignore all sorts of sub­tleties is the period before that. To nar­row down things fur­ther the Palaeolithic is sub-divided into three sec­tions, Lower, Middle and Upper. Again, roughly speak­ing, the Lower Palaeolithic is the time of early humans, the Middle is the time of Neanderthals roughly 300,000 BCE to 35,000 BCE, and the Upper Palaeolithic is the period after that with Homo Sapiens.

This gives the astro­nom­ical read­ers a rough idea of when we’re talk­ing about. Archaeological read­ers could very eas­ily pick holes in more or less everything I’ve said about the dates. One import­ant reason we’ll get to later is that when we use terms like Bronze Age or Palaeolithic, we’re not dir­ectly talk­ing about a spe­cific time, we’re talk­ing about the tech­no­logy we find that’s asso­ci­ated with a spe­cific time. So some ‘peri­ods’ make no sense out­side of Europe. If you live some­where where Obsidian was much easier to get than Bronze, then it’s pos­sible local people never bothered with a Bronze Age.

Hayden & Villeneuve real­ise that evid­ence from the Upper Palaeolithic is scant, but they also recog­nise that the Upper Palaeolithic is not just a time, but it’s tied to a place. What they’re inter­ested in is whether or not eth­no­graph­ies of mod­ern hunter-gatherer soci­et­ies can give us inform­a­tion about pos­sible uses for astro­nomy. You can’t simply say that mod­ern hunter-gatherers from now were exactly like hunter-gatherers twenty thou­sand years ago, but you can see if tack­ling astro­nom­ical prob­lems pro­duces debris sim­ilar to what archae­olo­gists find. You can also see if there are com­mon fea­tures in astro­nomy around the world from hunter-gatherers. If you can see hunter-gatherer astro­nomy in action then you have clues why hunter-gatherers used astro­nomy in the past and that can pro­duce work a lot more inter­est­ing than “there’s marks on this bone, people could be count­ing moon phases.“
Continue read­ing

Copernicus and the Star that was bigger than the Universe

The constellation Delphinus
Standard

I’ve been try­ing to watch Cosmos by Carl Sagan. I’ve never seen it and it’s prov­ing to be a bit of a struggle. He def­in­itely can write. Some of the sequences are fant­astic, but some of it is badly dated. The thing that really grates to me is his dis­missal of Ptolemy and his geo­centric uni­verse. For Sagan at best Ptolemy’s sys­tem held back astro­nomy by 1,500 years. At worst he’s only worth men­tion­ing to say he’s dead wrong, like in the first episode.

It’s not really fair to lay into Sagan for his atti­tude to Ptolemy. His work is a product of its time and it was writ­ten over thirty years ago. But the idea that Ptolemy was clearly wrong seems to the pop­u­lar under­stand­ing of Renaissance astro­nomy. The ques­tion here is Why did some people oppose the helio­centric the­ory of the uni­verse? not Who in their right mind would accept it? It over­looks the power of the Ptolemaic sys­tem. If you fol­lowed Ptolemy’s work you could pre­dict where the plan­ets would be with enough accur­acy for naked-eye astro­nomy. If Copernicus had only used simple circles, then his model might have seemed bet­ter, but he too needed to add epi­cycles and fudges to make his sys­tem match the observ­able sky. It needed fewer epi­cycles, but it was hardly perfect.

Popular belief is that the prob­lem was solved when Galileo picked up his tele­scope and proved the helio­centric the­ory. In fact a recently pub­lished paper by Christopher Graney, The Telescope Against Copernicus: Star Observations by Riccioli Supporting a Geocentric Universe in the Journal for the History of Astronomy shows that the tele­scope could have dealt a ser­i­ous blow to the Copernican model of the uni­verse.
Continue read­ing

Archaeologists prove the secret to a successful date is knowing what is on the menu

Standard
Bora Bora Dining and Food at Sunset

Knowing about food will increase the suc­cess of your dating

ResearchBlogging.orgLooking from the out­side, one of the most under­rated areas of archae­olo­gical research at the moment is the Archaeology of the Pacific. It’s pos­sible to make excit­ing dis­cov­er­ies any­where in the world. In Polynesia though, it’s hard not to. The reason is that Polynesian archae­ology has an odd con­tra­dic­tion. There’s been some excel­lent research done in the Pacific, yet it’s likely to be wrong. The prob­lem is in the dating.

Take Easter Island. The big story there is the eco­lo­gical col­lapse of the island. We know there was an eco­lo­gical col­lapse because set­tlers arrived AD 800, their set­tle­ment pat­terns changed around AD 1200 and when they were dis­covered by Europeans there were rel­at­ively few people on the island. We know they were on the island in AD 800 because that’s been radiocar­bon dated. If those dates were wrong, like if they were too old and set­tlers arrived later, then it’s not just a mat­ter of tweak­ing dates on the timeline in text­books. Suddenly there’s no native-caused pop­u­la­tion crash to explain.

Across the Pacific it turns out that many radiocar­bon dates are too old. Testing the human factor: radiocar­bon dat­ing the first peoples of the South Pacific by Petchey et al. (2011) is a paper that helps explain why, but also shows which dates are accur­ate. First here’s a brief reminder on how radiocar­bon dat­ing works.
Continue read­ing

8000 years of genetic engineering in your fruitbowl

Kadali. Photo (cc) Dinesh Valke
Standard

More blog­ging about research, without a Research Blogging logo, because this is way out­side my area of expert­ise — but it looks inter­est­ing. I spot­ted it going through the accep­ted papers list at Annals of Botany and ser­i­ously con­sidered put­ting this for­ward for a press release. I decided not to — I don’t fully under­stand it — and blog it instead. So I’ve been wait­ing for this to come out and slightly miffed that I missed it due to a cold. It’s not in the prin­ted journal yet, but you can see it now, and look at what I get wrong because it’s an open access paper.

The reason I’m going to make a fool of myself and blog it any­way is that this is research that is import­ant to the ori­gins of agri­cul­ture, one of the BIG archae­olo­gical prob­lems. And it’s about bana­nas, and everyone’s famil­iar with bananas.

Bananas are actu­ally strange. Aside from the fact that banana plants ‘walk’ (not really, see this excel­lent blog post), they’re also all clones. I also have to admit that if I saw a banana in the trop­ics I prob­ably wouldn’t recog­nise it. The big yel­low curvy fruit I think of as a banana is just one of many vari­et­ies. As a starchy plantain Musa (some of which are bana­nas) are a staple diet in Asia. They have been for thou­sands of years and they’re sterile so there’s a bit of a mys­tery. How can they still be here?

Kadali. Photo (cc) Dinesh Valke
Kadali, a type of Musa plantain, like banana. Photo (cc) Dinesh Valke.

The bana­nas we have today are the products of thou­sands of years of care­ful selec­tion for spe­cific traits by farm­ers. The ancient people doing this had no concept of ‘genes’, but if we were to do the same sort of thing today we’d be genet­ic­ally engin­eer­ing the plant. The reason ancient people did this is because edib­il­ity and seeds are prob­ably not com­pat­ible in bana­nas. Get a muta­tion without seeds and you have an edible berry. You don’t have seeds though so you have to start propagat­ing it more inventively.

Lack of banana sex means that the genetic diversity of these plants is very lim­ited. If you have a pest that can kill one plant, you’ve got a pest that can wipe your entire crop and you neigh­bours’ crops. So it would be amaz­ingly help­ful to be able to trace back the genetic his­tory of bana­nas to see where they came from and how they were domest­ic­ated into their cur­rent form. That’s what the authors of ‘Did back­cross­ing con­trib­ute to the ori­gin of hybrid edible bana­nas?’ pro­pose to do.

What they’ve found is that it looks like edible bana­nas are hybrids. That might not be such a sur­prise. What they’ve also found though is evid­ence of care­ful thought in hybrid­isa­tion to favour some traits over oth­ers, using a tech­nique called back­cross­ing. I had to have this explained to me.

You have two banana plants A and B. If you cross them you can get a hybrid banana AB.

Basic diagram of banana genetics

Banana Genetics

Backcrossing is when you take this hybrid and cross it back with an earlier gen­er­a­tion. So if you take your AB banana and back­cross it with an A banana you get banana with much more A genes in it than B genes. You can take this new hybrid and back­cross it again with A or B to pro­duce the next gen­er­a­tion and so on. The authors have a math­em­at­ical model for this and I won’t pre­tend I under­stand it. It’s a shame, because that’s most of the paper.

With my archae­olo­gical hat on, it’s a use­ful paper. If you’re inter­ested in how the trans­ition to agri­cul­ture occurred in south Asia then clearly under­stand­ing banana domest­ic­a­tion is import­ant. The ancient bana­nas them­selves have long rot­ted away, to being able to pull apart the genes of a banana to see how it was domest­ic­ated is a massive help. If this paper is right, and the authors pro­pose a few exper­i­ments to test the idea, then the banana is the res­ult of some very clever and select­ive breeding.

The reason I’m par­tic­u­larly excited is that Annals of Botany also had a paper on domest­ic­a­tion of Pitaya di Mayo recently by eth­no­bot­an­ists. This was a study of domest­ic­a­tion as it hap­pens. The kind of local selec­tions for spe­cific traits that Mexican farm­ers are using for pitaya look like they’d pro­duce the kind of com­plex genetic his­tory being found in bananas.

I live in a tem­per­ate zone, so the limit of my banana exper­i­ence till now has been that it’s a deli­cious, yel­low and some­times humour­ous fruit. Papers like this show that the banana going soft in your fruit bowl is an eight thou­sand year old con­nec­tion to some very clever farmers.

Past lives caught in the dust of trees

Standard

ResearchBlogging.org I’m cur­rently work­ing at the Annals of Botany to help out with their social media side. There’s a bit more to it than subtly drop­ping links to their site, like this one. At the moment I’m strug­gling with the Facebook integ­ra­tion, but there’s a fun side too. I wouldn’t have browsed AoB if I’d not been hired, and that means I would have missed out on papers like Phytoliths in woody plants from the Miombo wood­lands of Mozambique by Julio Mercader and his team at Calgary. I’ll admit the art­icle title doesn’t say much to the lay­man, but it’s actu­ally some­thing deeply cool that I didn’t find out about till my MPhil.

If mega­liths are big stones and micro­liths are small stones like arrow­heads, then phyto­liths are clearly phyto-stones. Phyto– in this case mean­ing plant.

Phytoliths are micro­scopic stones formed in some plants. When a plant’s roots draw up water they also draw up the min­er­als dis­solved within it. In the case of the silica this gets pulled out of the water and depos­ited either in the cells or between the cells. The exact shape of the phyto­liths var­ies on the part of the plant the silica is depos­ited in, the avail­ab­il­ity of silica and, most excit­ingly for archae­olo­gists, the spe­cies of the plant.

Phytoliths are use­ful because nor­mally bio­lo­gical mater­ial doesn’t hang around long in the soil. Once some­thing is dead it’s lunch for some­thing else. Phytoliths are bio­lo­gical mater­ial but not organic, so they don’t break down in the same way. Mercader et al. are clear that’s is not an unam­bigu­ous relal­tion­ship. Time still has an effect, but it’s easier to find phyto­liths than it is to find organic remains for plants. Still as use­ful as they are, phyto­liths alone are not enough. A hand­ful of phyto­liths under a micro­scope would just look like a nobbly (or smoothish) thing. If you haven’t seen what a baobab phyto­lith looks like, you’re not likely to guess from simply look­ing at the phyto­lith and this is where Mercader et al step in.

Elephants in Miombo woodland. Photo by Jussi Mononen.

Elephants in Miombo wood­land. Photo by Jussi Mononen.

If you’re inter­ested in study­ing the palaeoe­co­logy of Africa in the past you’ve been rel­at­ively lim­ited to north of the equator. Mercader spot­ted that the biggest phyto­chor­ion (plant eco­sys­tem) south of the Sahara is the Miombo wood­lands. It’s huge. It runs from Angola and Namibia in the west to Mozambique in the east and from the Tanzanian shores of Lake Victoria in the north to Botswana and South Africa in the south. The dom­in­ant tree is Miombo, hence the name, which refers to a num­ber of trees of the same genus, but with dif­fer­ent spe­cies. Obviously it’s a cru­cial zone for under­stand­ing the eco­logy of sub-Saharan Africa, but no-one has described the phyto­liths of the region.

Miombos Botanical Transect after Mercader et al.

The area stud­ied was a tran­sect through the forest between the Lake Niassa shore at Metangula and the high­lands at Njawala, a dis­tance of 50km and a rise from 465m above sea-level to 1841 above sea-level. They also used indi­gen­ous col­lect­ors to sample the flora in a 5km radius around Metangula and Njawala. They estim­ate they got over 90% of the spe­cies used by the nat­ive peoples. Given that a lot of usage is likely to be dom­in­ated by rel­at­ively few spe­cies, that’s a lot of plant mater­ial. There’s then a LOT of list­ing and descrip­tion of phytoliths.

The com­mon fea­ture that amazes me is how small many of these phyto­liths are. Some are just 20–40 μm long. A micro­metre (μm) is one thou­sandth of a mil­li­metre. Despite this Mercader et al, point to the phyto­liths at the other end of the scale, some are around 200μm in length and over half are over 50μm. This means if you use stand­ard tech­niques to sieve for phyto­liths using a 50.238 to 63.246μm cut-off, you’ll miss all these lar­ger phyto­liths. That’s going to mat­ter if what you want to find evid­ence of a ‘Zambezian’ forest at an archae­olo­gical site.

It’s the sort of sci­ence that is easy to over­look. The authors don’t con­clude that whole text­books need to be re-written or that our under­stand­ing of Africa’s past has to be rebuilt from scratch. It’s also the kind of sci­ence that’s easy to whine about. Here they are, pick­ing flowers to exam­ine tiny stones in the stems rather than just appre­ci­at­ing the beauty.

But it’s also the kind of sci­ence that increases the amount of beauty and mys­tery in the world.

Until I took my MPhil, I was com­pletely ignor­ant of phyto­liths. I could view the same plants an archaeo­bot­an­ist, but saw a lot less. Before I read this paper I didn’t know that that the Miobos wood­lands were unex­amined. Knowing that these things are out there opens up new pos­sib­il­it­ies for what can be done. At Çatal­höyük they’re examin­ing phyto­liths left behind in what are almost shad­ows of woven bas­kets to flesh out details of human life in the past. In the case of this paper, it provides a bench­mark for meas­ur­ing future study­ing against. It’s detailed, metic­u­lous and some­times opaque to the non-specialist, but it’s also a descrip­tion with last­ing value. Currently pub­lic­a­tions are often judged on cita­tions garnered over a few years. That misses the value of this paper as it will be import­ant for dec­ades. Indeed, if this eco­sys­tem sud­denly becomes a tar­get for eco­nomic devel­op­ment it could even be import­ant for cen­tur­ies as a snap­shot of the cur­rent state of the Miombos woodlands.

If you want to see the phyto­liths they found, you can down­load the paper for free.

ResearchBlogging.orgMercader, J., Bennett, T., Esselmont, C., Simpson, S., & Walde, D. (2009). Phytoliths in woody plants from the Miombo wood­lands of Mozambique Annals of Botany, 104 (1), 91–113 DOI: 10.1093/aob/mcp097

Photo credit: Elephants in Miombo wood­land. Photo by Jussi Mononen.

Planets and Anomalies in the Antikythera Mechanism

Standard

This post was chosen as an Editor's Selection for ResearchBlogging.orgMathematicians have a concept, Omega, that is defined as some­thing so huge that any attempt to define it actu­ally defines some­thing smal­ler. In a sim­ilar vein I reckon that any attempt to describe the ingenu­ity of the Antikythera Mechanism actu­ally ends up describ­ing some­thing less ingeni­ous instead. More research on the device has been pub­lished recently in the Journal for the History of Astronomy. I real­ise that people might be drop­ping on to this entry from a search engine, without hav­ing read any of the earlier posts, here’s a quick recap of what the mech­an­ism is.
Continue read­ing

Preserving a culture in wild honey

Standard

This post was chosen as an Editor's Selection for ResearchBlogging.org

What is her­it­age?” sounds like the kind of essay ques­tion a lec­turer might set when they run out of inspir­a­tion. It depends where you ask it. In some places it’s a ques­tion that car­ries a sting for the unwary. In the UK it’s almost always old build­ings. Sometimes it’s very old build­ings, but we build our her­it­age around the things we build. Sometimes a place can have a his­tor­ical potency, like a medi­eval bat­tle­field, but usu­ally we insist that some­thing leaves a mark before we acknow­ledge its his­tor­icity. It’s not sur­pris­ing. The UK is an indus­trial soci­ety. It’s a settled soci­ety. So is the rest of indus­tri­al­ised world. So how to you even start to exam­ine the her­it­age of a non-industrial soci­ety? Is the very concept of her­it­age loaded in a way that dis­em­powers some peoples? Mick Morrison, Darlene McNaughton and Justin Shiner have a paper ‘Mission-Based Indigenous Production at the Weipa Presbyterian Mission, Western Cape York Peninsula (1932–66)’ that tackles the prob­lems of power in 20th cen­tury Australia by look­ing at indi­gen­ous activ­ity around Weipa.

Weipa, North Queensland. Image © Google, used under edu­ca­tional terms.

Weipa is in the north­ern part of North Queensland on the west side of Cape York, the pointy bit at the top of Australia. It’s around here that the Dutch made first land­fall in Australia. The set­tle­ment was built due to the arrival of a Presbyterian Mission in last years of 19th cen­tury. The mis­sion was moved closer to the shore and it’s the later mis­sion that the art­icle is about. There’s a plan of the mis­sion and the first thing that struck me was the pos­i­tion of the Boy’s Dormitory and the Girls Dormitory. I wondered where the adults slept, then I wondered why the chil­dren were sleep­ing in dorm­it­or­ies any­way and not with their fam­il­ies. Finally, because I’m a bit slow of think­ing, I real­ised what the mis­sion was doing there.
Continue read­ing