- Αγία Γραφή περί Προέλευσης του Ανθρώπου Νο2 - .-= ΜΥΘΟΣ & ΘΡΗΣΚΕΙΑ =-.

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Τόσες εκατομμύρια μεταλάξεις, δεν χρειάστηκαν, κατά τους εξελικτές, ούτε για όλα τα ειδη.....Λιγότερες, έκαναν την αλυσίδα των ζώων, μέχρι τον ανθρωπο,σύμφωνα με τους εξελικτές

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ο κ. Λένσκι, λέει,οτι οι αλλαγές που παρατηρήθηκαν, δεν είχαν καμία σχέση με εξέλιξη, αλλά, με προσαρμογή, δεν έχουν καμία σχέση με ότι περίμεναν ,σε επίπεδο μετάλλαξης,συγκρινόμενα τα νούμερα των πολλαπλασιαζομένων βακτηρίων,με τις εκατομμύρια μεταλλάξεις,που οι εξελικτικοί,ισχυρίζονται, ότι άλλαξαν και έδωσαν, αυτή τη ζωή στον πλανήτη....Ούτε τυχαία, ούτε ως εξέλιξη, έγινε η ζωή...

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Πρώτον είσαι βλάκας και δεν μπορείς να συσχετίσεις εξέλιξη με προσαρμογή, οι οργανισμοί εξελίσσονται επειδή πρέπει να προσαρμοστούν. Αυτή ακριβώς είναι και η ορολογία του Δαρβίνου, adaptation. Δεύτερον, δεν είναι βιβλίο είναι επιστημονική εργασία, ημιμαθή

Τέλος το ανωτέρω λινκ είναι ΟΛΟΚΛΗΡΗ η εργασία του Λένσκι, ακριβώς με τον τίτλο που έδωσες, διάβασε το συμπέρασμα στο τέλος που αποδεικνύει ΠΟΣΟ ΗΛΙΘΙΟΣ και ευκολόπιστος είσαι

Αντιγράφω απλώς:

Conclusions

For over a decade, my group has maintained 12 populations of the bacterium Escherichia coli, founded from the same ancestor, in a simple defined laboratory environment in which glucose provides the sole source of carbon and energy. The evolving populations have undergone more than 20,000 generations of binary fission. Each populations had a billion or so mutations apperar, although only a tiny fraction were actually substituted in the population.

Extensive phenotypic evolution has occurred, including substantial gains in competitive fitness. After 20,000 generations, the evolved bacteria on average grow about 70% faster than the ancestor when they compete in the same environment. Average cell size also dramatically increased in evolving populations. The evolved bacteria have tended to become glucose specialists, with mostly subtle reductions in many other catabolic functions. This specialization reflects pleiotropic trade-offs of mutations that are benficial in glucose medium, much more than it does drift accumulation of neutral mutations in unused genes. Several populations evolved defects in DNA repair and became hypermutable as a consequence, but the mutator lines don not exhibit proportionately greater adaptation or specialization.

The rate of phenotypic evolution has decelerated over time. Decelaration in the rate of adaptation reflects each population's approach to an adaptive peak or plateau, not an inability to measure further adaptation owing to non-transitive competitive interactions. Evolution was often parallel across the replicate populations, not only for fitness in the selec-

tive environment but also for cell morphology and underlying physiology as reflected by performance on other substrates and patterns of gene expression. On the other hand, such parallelism is surprising given that the populations relied entirely on new mutations for genetic adaptation. On the other hand, the large population size and large number of generations ensured that almost any one-step mutation was accessible in every population.

We are now in the midst of finding mutations that have been substituted in these evolving populations. Several different approaches are being used, including sequencing both candidate and random genes. Once a mutation of interest is found, the gene must be manipulated, such as by moving the mutation onto an otherwise isogenic background, to test its effects on fitness and other traits of interest. For example, in the course of screening catabolic breadth, we found that all 12 populations had lost their ability to grow on ribose. Molecular genetic analysis found similar,although not identical,deletions of the rbs operon associated with an adjacent mobile genetic element. Both spontaneous and engineered mutations that eliminated this operon were produced in the ancestral background, and these mutations were shown to confer a selective advantage in the environment used in the long-term experiment. Similarly, evolved changes in gene-expression profiles led to a discovery of point mutations in the spoT gene in 8 of the 12 populations. By precisely moving an evolved spoT allele into the ancestral genome, we showed that this mutation provided a significant competitive advantage in the environment of the long-term evolution experiment.

Άρθρο του ΙΔΙΟΥ του ΛΕΝΣΚΙ με τη φάτσα του Δαρβίνου στο πλάι...

Scientific knowledge may permit humans to guide future evolution

By Richard Lenski

Most of us think about evolution in the past tense. After all, we were first exposed to the concept of evolution when we saw dinosaurs and other fossils at museums. But evolution has not stopped; it is an on-going process. Charles Darwin emphasized this point when he closed On the Origin of Species by saying: “… from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.”

With patience and skill, one can even watch evolution in action in some organisms. Peter and Rosemary Grant have spent decades in the Galápagos Islands observing the evolution of beak shape in certain birds, known as Darwin’s finches, in response to changes in seed availability caused by a fluctuating climate and competition. Microbiologists, too, observe evolution in action, including bacteria that become resistant to antibiotics.

Because bacteria reproduce so quickly, we use them in experiments to test evolutionary hypotheses. For over 20 years and 45,000 bacterial generations, my students and I have maintained twelve populations of E. coli in small flasks of sugar water. We measure the process that Darwin discovered – adaptation by natural selection – by competing ‘modern’ bacteria against their ancestors, which we store frozen and then revive for the tests. Imagine if we could bring Homo erectus back to life, and challenge them to games of football and chess! In our flasks, the modern bacteria outscore their ancestors in the struggle for existence.

You might wonder if the twelve lineages improved in the same or in different ways. Just how repeatable would evolution be if, in the metaphor of Stephen Jay Gould, we could replay the tape of life? On the one hand, mutations are random, so the lineages would tend to diverge. On the other hand, selection would favor the same adaptations because they live in identical environments. We have seen many cases of parallel evolution. The individual cells in all twelve lineages are larger than their ancestors, and all are more efficient at using the glucose in the culture medium we grow them in. Also, all twelve lines have similar mutations in several genes. In other ways, however, they have diverged, including a striking case where a single lineage evolved the ability to consume citrate, another source of energy in the medium, but one the ancestors could not exploit. In fact, a characteristic feature of E. coli as a species is that it cannot grow on citrate. We are now investigating the series of mutations that enabled this transcendent change.

What does evolution hold for the future? First, we humans have changed landscapes and climates, causing some species to go extinct, allowing others to colonize new habitats, and altering the selective pressures on those that survive. We have left a profound mark on the future evolution of life. Second, the increased density and mobility of our species provides new opportunities for pathogens to gain a foothold and evolve to exploit us. We ignore evolution at our peril. Third, we humans have acquired the scientific knowledge and technological tools to guide evolution in potentially useful ways. Researchers today can combine genes from distantly related species that cannot interbreed, synthesize genes that have never existed in nature, and evolve molecules in novel contexts. Moreover, and remarkably, the processes that allow evolution have been transported from nature into artificial realms. Self-replication, mutation, recombination and competition have been introduced into computer programs – ‘digital organisms’ – that can then evolve to solve computational problems. Similar approaches allow electronic circuits and even robots to evolve complex and interesting functions.

Darwin would be amazed to see where his ideas have led. Not only do we understand the history of life on Earth and the mechanisms of evolution far better than anyone in his day, we can directly observe the process of evolution and harness its power toward new ends.

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Richard Lenski is the Hannah Distinguished Professor of Microbial Ecology at Michigan State University. His research attracts world-wide recognition and focuses on the genetic mechanisms and ecological processes that drive evolutionary change. Lenski is a Member of the National Academy of Sciences and a Fellow of the American Academy of Arts and Sciences. The National Science Foundation supports his long-term evolution experiment with E. coli.

Βλέπεις τι λέει για την εξέλιξη ο Λένσκυ βλάκα; Για το Δαρβίνο; Είσαι βλάκας με περικεφαλαία ή απλώς εντεταλμένος;