Notes about biology

August 13, 2011 permalink

Floral Acoustics

I’ve heard that plants attract insects and other pollinators using nectar guides (nature’s own user interface!), but I’ve never heard of this adaptation: the plants depicted above manipulate sound rather than light to attract attention, a bit of floral acoustics.

Ralph Simon at the University of Ulm in Germany and his colleagues analysed the leaf’s acoustic properties and found that its unique shape produces a strong, constant echo across a range of sound-source angles. They then trained bats to seek a feeder hidden in artificial foliage. The animals found feeders topped with the cup shape in an average of 12 seconds — around half the time it took them to locate unadorned feeders or those under other leaf shapes.

(Via Nature)

July 3, 2010 permalink

James Joyce Synthetic Cell

To live, to err, to fall, to triumph, to recreate life out of life.

The above quote from James Joyce’s Portrait of the Artist as a Young Man was inscribed as a watermark into the DNA of the much-discussed synthetic cell created a couple of months back by Craig Venter’s team. From The Loom:

The scientists who produced the new synthetic cell copied the genome of a microbe, letter for letter, and then inserted the synthetic version into a host cell. To determine that their experiment worked, they needed a way to tell the genomes of their synthetic cells from the natural genomes that were their model. So they inserted “watermarks” into the artificial genome. These sequences of DNA (which spelled out the work of Joyce and others through the genetic code) sit in non-coding regions of the microbe’s DNA. As a result, these watermarks cannot disrupt any essential protein-coding genes or stretches of DNA that are vital for switching genes on and off.

August 29, 2009 permalink

Human uniqueness and the denial of death

[Geneticist Danny Brower] explained that with full self-awareness and inter-subjectivity would also come awareness of death and mortality. Thus, far from being useful, the resulting overwhelming fear would be a dead-end evolutionary barrier, curbing activities and cognitive functions necessary for survival and reproductive fitness. […] In his view, the only way these properties could become positively selected was if they emerged simultaneously with neural mechanisms for denying mortality.
If this logic is correct, many warm-blooded species may have previously achieved complete self-awareness and inter-subjectivity, but then failed to survive because of the extremely negative immediate consequences. Perhaps we should be looking for the mechanisms (or loss of mechanisms) that allow us to delude ourselves and others about reality, even while realizing that both we and others are capable of such delusions and false beliefs.

We humans are an odd lot.

From Nature’s Correspondance section, “Human uniqueness and the denial of death”, August 5, 2009. doi:10.1038/460684c;