Evolution details revealed through 21-year E. coli experiment
In 1988 an associate professor started growing cultures of Escherichia coli. Twenty-one years and 40,000 generations of bacteria later, Richard Lenski, who is now a professor of microbial ecology at Michigan State University, reveals new details about the differences between adaptive and random genetic changes during evolution.
Sequencing genomes of various generations of the bacteria, which had been frozen periodically over the years, Lenski and his team found that adaptive and random genomic changes don’t necessarily follow the same patterns. Rather than a plodding equilibrium, even in a consistent environment, the interplay between these two kinds of genomic changes “is complex and can be counterintuitive,” Lenski said in a prepared statement.
In some of the eraly stages of the experiment observations showed that adpatations followed what some would consider the classic and ievitable tendency of the bacteria to produce adptations that would ebenfit the survival of the bacteria. Yet as the experiment progressed – the 20,000 generation – some of the mutations did not seem to have any discernible advangtage of for the orgaisms. They were mutations that were neutral in terms of benefits to the bacteria or just random mutations. Is it really a wonder that nucletides would try out different products or be froced to by enviromental factors like variance in teperature, humidity and light. A commenter at the link seems to think since the experiment did not have a neat linear progression toward what we know in 20/20 hindsight is more complex and reached a dynamic stability the experiment failed to prove anything about how evolution works. On the contrary, evolution is the history of biological trial and error. It srtill is. Life in all its forms is beautiful, intriging and complex – all of the mechaims involved a far way from being fully explained. That bacteria, one of the less complex forms of life should try different kinds of macromolecular bonds is perfectly atutal. nature is in a way lazy. It is always lokking for an more enegitically favorable way of strurtucal support, energy storage, protection against destruction, nutrient transport, defense against environmental factors and destructive chemical bonds, regulation that maintains stability, movement, and storing the information that has helped it to survive. Human beings or the human brain does not involve itself at this level, they are issues resolved at the nucleotide and protein level. If the human brain in all its supposed perfection directed cellular function at the protein level, we could simply mentally repair cancer or heart disease. To regress, imagine those bacteria 4.6 billion years ago – about the age of when its thought some crude life began on earth. The bacteria in the experiment is a mere 20 years old. Imagine the sheer number of trials and errors that have taken places in 4.6 billion years of mutations – some to an organisms advantage, some neutral, some merely excess baggage. Just like those bacteria much of the human genome is excess baggage, is neutral, while and some is capable of and does in fact kill millions of us every year. Oncogenes are proof that if we had a perfect designer he or she designed a heart breaking defect into human DNA. One in a hundred human humans carry a mutation for heart disease. Again, given billions of years, our nucleotides are still trying to work out the best design. It doesn’t help that the environment we live in keeps changing so even if they suddenly got things perfect this year, next year they’d have to come up with more mutations to keep up. Nucleotides have no comprehension of perfection or divine insight, what they seem to strive for is surviving long enough to produce more nucleotides.
I was prepared to blame public education or private for that matter for anyone having the notion that evolution is guided by a kind of deluxe erector set of instructions in which the goal is to build ever more complex and beneficent beings, but I looked through a couple current high school level text books before i wrote this post and they do not meander off into any such quasi-philosophical views of evolution.
Painting features ‘oldest watch’
Art experts think they may have found the world’s oldest painting to feature an image of a watch.
The Science Museum is investigating the 450-year-old portrait, thought to be of Cosimo I de Medici, Duke of Florence, holding a golden timepiece.
Curators have sent their findings to renaissance experts at the Uffizi gallery in Florence, and are awaiting their comments.
The painting is being shown as part of the museum’s Measuring Time gallery.
The first watches appeared shortly after 1500 in Germany and horologists believe the picture, painted by renaissance master Maso da San Friano around 1560, “may well be the oldest to show a true watch”.
And we’ve been obsessed with time ever since.
inkbluesky 