Tuesday, September 2, 2014

Human Evolution - Out Of Africa, Assimilation, Multi-Regionalism

So much has happened in the field of human evolution in the last few years!

Two end member theories have been popular for some time. The Out Of Africa theory says that modern humans originated in Africa around hundred thousand years ago and then spread all over the world replacing local populations of humans from older migrations. On the other hand the multiregional scenario said that modern humans did not originated exclusively in Africa. Rather modern humans evolved from local populations everywhere i.e. eg. modern Chinese evolved from Homo erectus  (which migrated there from Africa several hundred thousand years ago) in China with some gene flow between regions.

That extreme multiregionalism has now been rejected by recent advances in understanding genetic relationships between human populations but in a way so has the extreme Out of Africa version. There is evidence now that modern humans interbred with older regional populations as they spread across the world. This is now termed Out of Africa with assimilation or as "leaky replacement" by some.

Chris Stringer a researcher at the Natural History Museum London writes a good summary of the various theories of modern human origins. It is open access and worth reading.

A short excerpt:

 ‘Modernity’ was not a package that had a single African origin in one time, place, and population, but was a composite whose elements appeared, and sometimes disappeared, at different times and places and then coalesced to assume the form we see in extant humans [6]. However, during the past 400 000 years, most of that assembly took place in Africa, which is why a recent African origin still represents the predominant (but not exclusive) mode of evolution for H. sapiens. Rather than saying ‘we are all multiregionalists trying to explain the out-of-Africa pattern’ [1], it would be more appropriate to say ‘we are all out-of-Africanists who accept some multiregional contributions’.

Thursday, August 21, 2014

On The Consequences Of A One To One Scale Map

 My Book Shelf # 30

I have just started reading A History Of The World In Twelve Maps by Jerry Brotton, an exploration of influential maps through our history that shaped the way we viewed the world and in turn how our cultural habits, religious beliefs and political power equations of the day shaped decisions of how and what to represent. Each period in our history argues Jerry Brotton gets the map it deserves. It promises to be a really interesting read.

Early in the introduction I came across this passage on the use of scale:

The only map that can ever completely represent the territory it depicts would be on the effectively redundant scale of  1:1. Indeed, the selection of scale, a proportional method of determining a consistent  relationship between the  size of the map and the  space it  represents is closely related  to the problem of abstraction, and has been  a rich source of pleasure  and  comedy for many writers. In Lewis Carroll's Sylvie and Bruno Concluded (1893), the other worldly character Mein Herr announces that 'we actually made a map of the country, on a scale of  a mile to the mile!' When asked if the map has  been used much,  Mein Herr admits, 'It has never been spread out'. and 'the farmers objected: they said it would cover the whole  country,  and shut out the  sunlight! So we now use the country itself, as its own map, and I assure you it does  nearly as well.' The conceit was taken a stage further by Jorge Luis Borges,  who, in his one-paragraph short story 'On Rigour in Science' (1946), recast Caroll's account  in a darker key. Borges describes a mythical empire where the art of mapmaking  had reached such a level of detail that 

the Colleges of Cartographers set up a Map of the Empire which had the size of the Empire itself and coincided with it point by point. Less Addicted to the  Study of Cartography, Succeeding Generations understood that this widespread Map was useless and with Impiety they abandoned it to the Inclemencies of the Sun and of the Winters. In the deserts of the west some mangled Ruins of the Map lasted on, inhabited by Animals and Beggars; in the whole Country there are no other relics of the Disciplines of Geography.

Borges understood both the timeless quandary and potential hubris of the mapmaker: in an attempt to produce a comprehensive map of their world, a process of reduction and selection must take place. 

Wonderful passage! (but i wonder not having  read the story -if the map was as large as the empire, where did they keep it? :) )  If you want a shorter summary of the book do listen to Jerry Brotton on BBC Pop-Up Ideas podcast -  Mapping History. It is an enjoyable talk.

Now,  back to reading!

Wednesday, August 20, 2014

Conversation With An Ecologist About Fossils And Conservation

T R Shankar Raman, an ecologist who blogs at View At Elephant Hills and tweets @mizoraman wrote in last week with a question about fossils, field work and conservation. It ended up being a long conversation via email and so with his permission I am posting our conversation below.

In geology, field sampling does lead to outcrops being damaged and in-situ context of important fossils being lost. At least when I was a student, these issues about how to go about working an outcrop so as to cause least damage to the outcrop and what are the ethics of fossil collection did not come up for any discussion. Do faculty discuss this with students these days here in India?  I don't see these issues being widely discussed in the geology community here. I will be talking to a palaeontologist to get her views about the legality and ethics of collecting fossils from private and public lands in India which I will write up as a blog post.

In the meantime, below is our exchange.

Shankar Raman-

if you have the time. If geologists find something like this, how do they decide whether to leave it in situ (conservation) or remove (collection) for study? How many of the scientific collections are then actually subject to study and make it into publications and how many are simply lost? If locations of such fossils are made public/advertised, does it lead to their loss or a kind of vandalism? (I ask because there are parallels from ecology/field biology of collecting animal or plant specimens and related ethical and conservation concerns.)

Suvrat Kher

you raise interesting and important issues. I do feel conservation issues in the sense of leaving fossils or minerals in situ have not been widely discussed in the geology community yet. On a broader scale geologists do agree that some sites are of great importance as a geological heritage and those should (and some are) conserved. The Geological Survey of India is working of an expanded list of geological sites that they will ask for protected status. But at an individual level, a geologist or palaeontologist working in a field area is likely to sample whatever is available (the feeling may be that someone else would sample it and scoop my research :) ).

Regarding whether fossil collections go unstudied, the answer is the age-old "it depends" on who did the collecting and when. For example the GSI has enormous collections of fossils from more than a century of mapping the country. Much of these lie in museums and archives, unstudied, although some GSI geologists do describe them in monographs and such. But more value addition in terms of their ecological and evolutionary significance remains to be done.

On the other hand academic departments have shorter term goals, limited funding and a pressure to publish (esp in recent times). Their sampling programs hence tend to be limited and focused and much if not all of the fossils eventually will be published. In some cases though palaeontology departments are on the wane and so yes their collection may remain unstudied.

In terms of keeping fossil sites secret, not sure how that will work. If you publish then the location has to be disclosed. That is scientific practice. Vandalism however is a real threat and is happening with private collectors making of with a bounty (example minerals like zeolites found around Pune are providing a fortune for dealers). I guess one can't protect the entire sedimentary basin but demarcating protected areas and provided funds to secure such sites is the best one can hope for. Perhaps we need to make a distinction of collecting fossils from private lands (with permission) versus protecting public sites which fall within National Parks and such. The U.S has such a distinction.  In any case unfortunately this is not given enough importance and if there is a law against collection nobody seems to be aware (including me!) of it and am sure it is widely disregarded.

thanks for making me think aloud about these issues!

Shankar Raman-

Thanks for your thoughtful response. I see the parallel concerns and differences that you describe. In our field of work, there are serious concerns regarding (a) collection of specimens (a significant number languish without final description with scientists who dont want to be scooped and dont want to share or deposit in museums), (b) possible impacts on the habitat and the population of the species in the area where the study or collection is carried out. So it is a matter of both ethical and conservation concern.

And this is not just restricted to India... listen to this NPR broadcast for instance, triggered by a paper in Science: http://www.npr.org/2014/06/18/318307574/is-collecting-animals-for-science-a-noble-mission-or-a-threat

In our field (wildlife conservation), there is also the related issue of tourism in natural areas and other threats such as poaching. So we always try to be careful and sometimes decide to not disclose a specific location of an endangered species (a rare orchid, say, the nest of a breeding hornbill, or a wild male elephant with huge tusks) or do so after some kind of embargo period or with less specific geographic coordinates. Striking a balance is tricky... one does not want to end up with a situation that further stifles genuine research and also creates more bureaucratic red-tape for permits.

Hence my email and reticence regarding specific details about the fossils before I understand how things play out in geology. About law: the Indian wildlife act does prohibit removal of plants, animals (even dead, body parts etc) or destroying habitat in any way. But if someone chips away a bunch of fossils or pockets/bags a few... will they be caught? If caught, will they be fined or acted against? No idea! You should do a blog post about this someday! Conservation is a general enough word to be relevant to artistic heritage, geology, and
wildlife!

Thanks for the discussion!

Tuesday, August 12, 2014

In Darwin's Footsteps: A Book On The Galapagos Daphne Major Finches

Years ago I read Jonathan Weiner's excellent book The Beak Of The Finch. He describes the work of Peter and Rosemary Grant on the finches of Galapagos Islands with its fertile volcanic landscapes and biodiversity having inspired another aspiring naturalist in the 1830's to great discoveries. The Grants studied for decades evolution of finch populations, observing in them natural selection in action.

Now they have written their own book- 40 Years of Evolution: Darwin's Finches on Daphne Major Island.

Jonathan Weiner writes about it in the New York Times:

They kept up their watch during years of downpours and years of drought — seasons of feast and famine for the finches. And Darwin’s process unfolded before their eyes in intense episodes that illustrated better than anything in the Origin the struggle for existence, and the ways that life adapts and emerges fitter from the struggle.

.. and on the possible beginnings of a distinct lineage -

Big Bird’s lineage has now lasted for 30 years and seven generations. The Grants are cautious about its prospects — “It is highly unlikely that we have witnessed the origin of a long-lasting species, but not impossible,” they write — but other scientists are buzzing.

This is exciting work, the stuff that inspires young students of the subject to push ahead with their own dreams and aspirations. The Grants are both 77 years young now... and still studying their beloved finches.


Monday, July 28, 2014

Some Interesting Podcast's I've Listened To Recently

I should be sharing this list more often-

1) On America's other migrant farm workers - Bees! Biologist Laurence Packer talks about the importance of bees in American agriculture. Incredible- millions of them are transported by trucks to aid in pollinating almonds and other fruit crops from one end of the U.S to the other!

2) Science Friday- Summer Book List 2014- What is not to like about a conversation that discusses a book like Proof- The Science of Booze!... and many more books featured in this talk.

3) Science Friday- Crafting Perfect Beer- more on the microbiology of beer and the burgeoning craft beer industry in the U.S.

4) Planet Money- The History of Light: Before there was the light bulb there was fat! Planet Money is one of my favorite podcast; it is economics explained with a light touch. This episode features how we got from candles made from cow fat and whale blubber to light at the flick of the switch and its economic implications in terms of the massive increase in human work productivity.

5) On Point Radio- The End of Night: A nostalgic look at what we have lost with our city life- the end of the night sky. Wonderful remembrances by callers too.

6) Fresh Air: To End All Wars: Its the 100th anniversary of the beginning of the Great War (World War I) and author Adam Hochschild discusses his book To End All Wars- you read this with a shudder- " I think the war remade the world for the worse in every conceivable way: It ignited the Russian Revolution, it laid the ground for Nazism and it made World War II almost certain. It's pretty hard to imagine the second world war without the first."