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Humans and Birds Use Same Mechanism to Produce Sound.

Birds and humans look different, sound different and evolved completely different organs for voice production. But now new research published in Nature Communications reveals that humans and birds use the exact same physical mechanism to make their vocal cords move and thus produce sound……

Švec: “To me it was very surprising and fascinating to discover that such different vocal organs make sound in the same way”.

According to Elemans the new discovery not only sheds new light on the sophisticated vocal talents of song birds. The discovery is also interesting and useful because it can be paired with the knowledge about another interesting vocal mechanism shared by some birds and humans: The neural mechanisms underlying vocal learning. Both songbirds and humans are not born with the ability to speak or sing, but must learn their language or song by listening to others, a process called vocal imitation learning or simply vocal learning.


Scientists Claim Brain Memory Code Cracked

Despite a century of research, memory encoding in the brain has remained mysterious. Neuronal synaptic connection strengths are involved, but synaptic components are short-lived while memories last lifetimes. This suggests synaptic information is encoded and hard-wired at a deeper, finer-grained molecular scale.

In an article in the March 8 issue of the journal PLoS Computational Biology, physicists Travis Craddock and Jack Tuszynski of the University of Alberta, and anesthesiologist Stuart Hameroff of the University of Arizona demonstrate a plausible mechanism for encoding synaptic memory in microtubules, major components of the structural cytoskeleton within neurons.

More here

First questions about LECA

We have seen that science has discovered the last eukaryotic common ancestor was essentially as complex as a modern day eukaryotic cell (see here and here and here).  Furthermore, I have argued that this complex cell plan that has defined eukarya since the time of LECA has worked to facilitate the eventual emergence of metaozoan-type complexity.

So perhaps it is time to begin contemplating the origin of this complexity.

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LECA Front-loaded Metazoa?

In the previous posting, we saw that the last common ancestor of all eukaryotic organisms was quite modern-like in terms of its complexity.  Doubt me?  Well, here is Figure 3 – Major transitions in evolution of the endomembrane system – from Evolution of the eukaryotic membrane-trafficking system: origin, tempo and mode).  Have a look:

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Spock’s Scanner

Ever wonder what Mr. Spock was seeing when he looked into his scanner? Wonder no more:

Adherens junctions poised to appear

In the previous posting (which was originally posted over a year ago), I was able to track down some papers which uncovered evidence for the existence of various adherens junctions proteins in unicellular organisms.  Well, a few days ago, I had the time to probe databases with sequence from human genes in search of homologs for adherens junction proteins in unicellular organisms.

Recall the basic components of an adherens junction as seen in the below figure:

As you can see, the cadherin is the membrane protein used to link cells together. The cadherin, in turn, is linked to the cytoskeletal microfilaments through a complex composed of beta-catenin, alpha-catenin, alpha-actinin, and vinculin.

Below is a table that lists what I found.

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