Conceptualizing Evolution of A. Sediba And Homo With Diagrams

The recently named new hominid species from S. Africa Australopithecus sediba has generated a lot of articles and blog posts. Many of them are very informative and content rich. But going through them I found them to be text heavy and lacking in diagrammatic representations.

Its confusing trying to wade through all the possible scenarios of the relationship between Au. sediba and Homo that are being discussed. I found thinking of the relationships with diagrams eased some of that confusion.

So this post is relatively light on text and diagram rich. Here are evolutionary scenarios depicted in simple diagrams that I created:

1) Au. Africanus evolved into Au. sediba which then later evolved into Homo.

This scenario envisages evolution of a new species via phyletic gradualism in which the entire species transforms into a new species. Although new species could arise this way, in this case the fossils of Au. sediba are younger (1.7 - 1.9 mya) than the oldest representatives of Homo ( 2.3 mya) negating the possibility that Au. sediba transformed into Homo. John Hawks though outlines a situation where this model could still hold and that would be if the oldest representatives of Homo have been misclassified as Homo and are really australopithecines.

The next two scenarios are the ones favored by the authors of the paper.

2) Au. sediba is derived via cladogenesis from Au. africanus at an early date possibly as early as 3 million years or so.  Homo then evolves in a later speciation event from Au. sediba. The recently found fossils of Au. sediba represent a relict population. This is the punctuated equilibrium model of speciation wherein one population of a species becomes reproductively isolated from other populations and evolves into a new species. The ancestor and descendant species may then co-exist for a time period. 

3) Au. sediba and Homo share a common ancestor..either Au. africanus or a close cousin.

In both the above scenarios (2,3) the similarities between Au. sediba and Homo are due to a shared ancestry.

4) Many critics of the above interpretation prefer the following scenario.

Au. sediba evolved either via phyletic gradualism or via cladogenesis from Au. Africanus in S. Africa. Homo evolved from some other lineage of bipedal hominid elsewhere.  I have shown Au. afarensis as an ancestor of Homo but only as an example. There may have been several lineages of bipedal hominids and Homo could have been derived from within any one of them.

In this case the similarities between Au. sediba and Homo are a result of convergent evolution in response to similar locomotary and dietary pressures.

5) Donald Johanson, discoverer of Lucy favors this scenario.

Au. sediba has been misclassified as an australopithecine. It is really a representative of Homo. But Homo likely evolved somewhere in eastern Africa about 2.3 million years ago and the fossils found recently in S. Africa which are 1.7. to 1.9 my old is a migrant Homo population, descendants of east African Homo.

Plenty to chew on..

Twittering During An Earthquake

All you Geo-twitterers take note:

Source: xkcd

That puts social networking on a very shaky ground.

Undamming India: Two Dams On Himalayan Bhagirathi River Cancelled

A high powered committee created by the Prime Minister of India reviewed the social and environmental aspects of two planned dams on the Bhagirathi river, a Himalayan tributary of the Ganga and recommended that the projects be shelved.

Respect for social and religious sentiments of the people along with environmental concerns was the reason given.

Mr. Jairam Ramesh the Minister for Forest and Environment was one member of the committee along with Finance Minister Pranab Mukherjee and Power Minister Sushil Shinde.

This good news though hides a more ubiquitous failure and that is that the system put in place to review large infrastructure projects did not object to these projects. The Environmental Impact Assessment (EIA) which should have raised a red flag instead waved a green one. Its only a higher level intervention by the Prime Minister that has saved a stretch of this river from being reined in.

In fact this high powered committee reassessed the EIA and found violations in the environmental clearance process.

The EIA needs to be fixed from the bottom up and that means fixing some of its the structural problems. As I have written before the EIA is becoming a rubber stamp for getting clearances for projects. The Terms of Reference are deliberately kept restricted. Not enough time is given for comprehensive studies. And it does not have the authority to make the project conditional to the findings of the study.

This is what Mr. Jairam Ramesh needs to fix.

If he has to run to the Prime Minister, let it not be for creating another high level committee to specially look into one project  ...but to plead to the PM that the ground level process set in place to review all big projects have real teeth and muscle to delay, redesign or need be cancel projects. He should ensure that fly by night consultants who do incredible shoddy science are fired and permanently blacklisted and projects not started until a serious scientific assessment of the project is complete.

There seems to some movement on that front. Mr Ramesh has ordered that the cumulative impact of a cascading series of hydroelectric dam projects on the river Alaknanda in Uttarakhand and the river Teesta in Sikkim be studied. Previously the EIA were restricted to studing each dam in isolation as if nothing was happening upstream and downstream of that one project.

The river Bhagirathi falls in the Ganga basin. The Ganga is a pretty special river and so complaints about damage to religious sentiments and the ecosystem have plenty of sympathetic ears. There is a special Ganga River Basin Authority set up to restore and clean up the river.

Other rivers and projects are not that lucky and overall the system put in place to evaluate projects is failing.

That's what needs to be corrected pronto if India want to develop while still protecting critical, sensitive and bio-diverse ecosystems.

What Makes Chimps and Humans Different

Yeah..yeah...chimps are hairier and while in heat the bare skin of a female chimp's bottom gets all red and swollen..I haven't noticed that in humans...but really deep down the question  most people want to ask is why is there so much cognitive difference between chimps and humans.

 Almost As Brainy

What is the genetic basis of the brain differences between chimps and humans and how did they come about through evolution?

On NPR's Cosmos and Culture blog, Ursula Goodenough has a terrific post on gene regulation and brain development and research that is beginning to tease out the reasons for the differences between chimps and us.

...brains build themselves. Bottom up. When A happens, that allows B and C to happen; B allows D and E to happen; and so on.

Because brain development is so contingent on what has gone on before, it's pretty easy to alter what happens. For example, if the pioneer neurons in our example carried a switch mutation that prevented them from secreting the nerve growth hormone at the appropriate time, the next phalanx of neurons wouldn't move towards them and might, instead, pick up on a more distant hormonal signal from another brain region and move in that direction, forming synapses with a new set of neurons altogether. A brain is still constructed, but it will have different kinds of neural pathways and connections and hence, perhaps, different ways of doing things.

So now we can return to the chimp-human question. If the chimp and human protein-encoding genes are virtually all the same, then are there any interesting differences in their switch regions? Given the bottom-up nature of development, mutant switches could have large-scale consequences.

The answers that is emerging is ..yes..there seems to be differences in switch regions between chimps and humans.

The post is a quick lesson in the genetic innovations that occured through the transition from unicellular to multicellular life and fast-forwards to brain development and the role of genetic switches in evolving human-specific patterns of regional differentiation of the brain.

The question of when these changes in the brain occurred is not dealt with but a reasonable answer would be.. beginning with the Homo lineage about 2 million years or so and continuing ..even today? It was about 2 mya when we begin to see in the hominid fossil record a noticeable departure (increase) in brain size compared to the earlier fossil hominids and modern chimps ..accompanied by a more varied tool.

I suspect these kind of discoveries will provide fodder for the many controversies about the emergence of "modern humans". Did the sudden emergence of a new genetic switch enable symbolic behavior or ...language?

This post by Ursula Goodenough deals with the developmental aspects of brain differences. An evolutionary narrative awaits.

Cutting Academic Programs In U.S. Universities

A friend sent me an article from the Chronicle Of Higher Education entitled  Disappearing Disciplines.(behind pay-wall)

It illustrates quite well the problems and conflicts arising out of budget cuts and program streamlining initiatives many U.S. Universities are being forced to undertake.

Administrators and faculty are at times working together to limit the damage and at other times the two are at loggerheads, often decisions are being taken by Administration without involving faculty. The Faculty especially  worry that programs are being evaluated using only one measure like enrollment number that might lead to programs considered by faculty as essential for a well rounded education to be eliminated.Or by completion rate which might put pressure on academic programs to lower standards to push up graduation rates.

Here is a nice glimpse into the different priorities of those involved:

Administration view:

The 14 universities in the Pennsylvania State System of Higher Education (which does not include the Pennsylvania State University system) have been ordered this spring to review all of their "low completion" programs—that is, those with fewer than 30 graduates during a five-year period. The campuses are being encouraged to consider consolidating or suspending those programs.

"With the limited resources we have, we want to be sure that our academic programs are appropriate to our universities' needs and to the needs of the commonwealth," says Kenn Marshall, a spokesperson for the system. "We are looking long-term, to make sure that we can operate within a balanced budget."

And the faculty view:

Several of the small departments that have come under scrutiny are philosophy programs. Wendy Lynne Lee, a professor of philosophy at Bloomsburg University of Pennsylvania, has been leading a campaign to protect those departments.

"A university without a robust philosophy major ... is simply anathema to the mission of a university," she wrote on Leiter Reports, a philosophy blog, in March. "This is not about enrollment; it is about what distinguishes a trade/professional/technical school from a university. Every single minute we are willing to play ball according to the chancellor's rules, which fallaciously link enrollment to program quality, we are in point of fact conceding to play by these rules."

At my Alma Mater Florida State University the geology program has been eliminated as an individual graduate degree program and has been merged with Oceanography and Meteorology. Several of the faculty I knew have had their contracts canceled.

Its a painful situation. Some feel that involving faculty in the program evaluation process might help mitigate the sense of marginalization faculty feel..there have been small success stories where faculty persuaded administration to retain a program..that however is no consolation for those who do get sacked. And often the manner in which lay-offs have occurred rankles. Prof. Froelich Jr. of Florida State University points to oceanography in which he has been tenured since 1978. The University recently encouraged the department to hire two new tenure-track appointments and then fired them 6 months later. 

Meanwhile Robert C. Dickeson, a higher-education consultant and a former president of the University of Northern Colorado has come up with a list of factors to consider when evaluating programs:

• History, expectations, enrollment demographics. (For instance, does the program cater to part-time, older students to help them complete degrees?)
• Demand from incoming students
• Demand for program's courses to fulfill distributional requirements
• "Inputs," such as quality of faculty members, students, and curriculum
• "Outcomes," such as test scores and scholarly research
  Size, breadth, and depth
• Overall impact and "essentiality" to college's strategic plan
• Opportunity for saving or growing the program

Overall the message being sent out by faculty members is - we understand the Universities are in a crisis..but involve us in the restructuring process.