Human influence on biological speciation (NY Times)

This article (NY Times, may require registration) is interesting for many reasons. The main idea is to point out the influence that humans have on the evolution of other organism populations. The process of speciation seems to be moving towards hybridization and selection for intermediate traits for many organism populations. Classification issues will abound - a good biology "hook" for the idea of representing "differentiated" cognitive resource populations.

A whole new twist on "I Can't Quit You Baby"

Patterson et al have published a study in Nature (press release) indicating that the common ancestry of humans and chimpanzees is more complex than suggested by recent and historic data interpretation. The new study, which utilized a large number of high fidelity DNA sequence comparisons, presents data that suggests that the common ancestor population split once, came back together to form a hybrid population, and then diverged once again to form the modern human and the modern chimpanzee. DNA sequence similarities (particularly on the X chromosome) indicate that the first population break resulted in the modern chimp line, and that the hybrid population evolved into the modern human.

..."Don'tcha realize sweet baby? Woman I don't know... which way to go. Woman I can't quit you babe." (from "I Can't Quit You Baby", a blues song performed by a number of great artists)

A distal enhancer and an ultraconserved exon are derived from a novel retroposon : Nature

A distal enhancer and an ultraconserved exon are derived from a novel retroposon : Nature

In essence: DNA sequencing of all modern vertebrates shows that there are many regions that are always the same, whatever the organism. Enter the modern "coelacanth", an organism (recently thought to be extinct) that has changed very little (in multiple measures) in hundreds of millions of years. When comparing the DNA of the coelacanth with vertebrates (especially mammals), it is found that some of the highly conserved regions in vertebrate DNA act as transposons (sequences of DNA that frequently switch position within the genome) in the coelacanth. Researchers looked at the vertebrate function of one of these transposon sequences and found that it had positioned itself within an RNA processing gene, making it possible for the cell to have another alternative splicing pattern for that protein product (thereby altering the function of the protein).

Potential difficulties with cognitive resource classification

For now, this is just a quick post so that I don't forget a thought that I had during yesterday's CogGroup presentation by JED. Before the presentation, I used a white board to draw a cladistic representation of a classification system for cognitive resources. One of the theoretical benefits of cladistic classification is that, as Dawkins points out in The Blind Watchmaker, with perfect information, and with consideration only of currently (emphasis mine) living individual organisms, we should be able to make a branching represenation that has only binary pathways. This is part of his discussion on dealing with intermediate forms in systemics - Dawkins argues that the biosphere is unique in that it is possible to perfectly classify organisms in unique and non-overlapping categories (i.e. an organism can only belong to one species, whereas I might want to classify my CDs by Mos Def and Talib Kweli as both "Hip Hop" and "Urban Folk").

Now let's shift into considering classification activities with regard to cognitive resources - the species of thought, which exist in what is called the noosphere. The thought I had yesterday is with regard to intermediate forms. I was showing my advisor how the cladistic representation has a "built-in" ability to show the results and process of at least one type of conceptual change (dual construction). The problem, though, is with the common ancestor: is it really "dead"? It seems that the context sensitivity and complexity of the neurocognitive system would make it very difficult to survey the cognitive ecosystem (an issue with "perfect information"), and anecdotal experience along with intuition tells me that the ideas that students have when they begin a learning process (the common ancestor) will likely persist beyond conceptual change. So, there is certainly divergence of a population and speciation, but the common ancestor still seems to survive. This common ancestor is, by definition, an intermediate form!

Ahhhhhh...now this feels familiar. A wrench in the works: cognitive evolution can occur within the neural life cycle. Must be on to something :) Now it's time to teach...