Laura Quinney, Brandeis University, Prof.
You have to compare at least a few dozen base pairs before you can see the uncanny way that organisms in the same genus match up far better than organisms in different classes for example. Here, for example, is an alignment of some cytochrome C amino acid sequences from various organisms for discussion see here.
If Wells were interested in giving his readers a useful graphic, he could have easily found something like this, published in a article of the Journal of Molecular Evolution: The following example comes from the mitochondrial DNA sequence data from Horai et al. See that page, notes for a course on evolution at Montana State, for further discussion.
A discussion of the sequence analysis and the mathematics of nested phylogenies is here: Even when different molecules can be combined to give a single tree, the result is often bizarre: A study using 88 protein sequences grouped rabbits with primates instead of rodents; a analysis of 13 genes in 19 animal species placed sea urchins among the chordates; and another study based on 12 proteins put cows closer to whales than to horses.
What Wells isn't telling you is that some of these results are not in fact ridiculous. Cows, for example, are artiodactyls which are indeed thought to be closely related to whales, a suspicion which has received striking confirmation from recent transitional fossil discoveries see the webpage of the discoverer Thewissen, http: Sea urchins phylum echinodermata do indeed group "among the chordates" but this is because they are a sister group to chordates, not within chordates as Wells implies.
This taxonomy is a long accepted fact see e. The very paper that Wells cites recognizes these distinctions explicitly.
The rabbits and rodents study, on the other hand, has methodological flaws although the two groups are indeed more distantly related than the nonexpert might expect. All of this is discussed in detail, with references, by talkorigins poster John Harshman.
The Root of the Tree of Life.
The 'Tree of Life' is the idea, most famously advocated by Darwin, that all known life is descended from a common ancestor and is connected by a phylogenetic 'tree': I believe this simile largely speaks the truth.
The green and budding twigs may represent existing species; and those produced during each former year may represent the long succession of extinct species. As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching and beautiful ramifications.
In IconsWells has a ball with recent scientific debates over whether or not lateral gene transfer mixed up ancient genomes so much that deepest branches of the tree are mixed up. Basically, some scientists have proposed that the idea of a single "last common ancestor" should be replaced with the idea of a "last common gene pool" that the extant three domains of of life -- eukaryotes, archaea and eubacteria, in one classification scheme -- gradually emerged from.
Carl Zimmer describes this as the 'Mangrove of Life' idea. Wells of course milks this for all it's worth, proclaiming the downfall of common descent and the 'uprooting of the tree' and whatnot, but he is distorting things. This entire debate is, among scientists, about the very oldest part of the tree, known as the ' root.
Apart from being the most remote event to study timewise, the question of the rooting of the tree is greatly complicated by lateral gene transfer, by differing rates of evolution between genes and lineages, by the fact that eukaryotes are the result of symbioses between archaea and eubacteria, and by the fact that, by definition, the Tree of Life has no outgroup, which creates technical problems for placing the root.
Scientists are attempting to discern the most ancient events in the history of life here, so complications are to be expected. One recent article that is highly skeptical of much of the work that Wells cites is Cavalier-Smith What Wells does not point out is that this entire controversy has precious little to do with eukaryote phylogeny which is coming along just fine, thank you, see e.The Spiders Part II: The Diamond Ship The Spiders Part II: The Diamond Ship () is a much less successful film than Part I.
Its storytelling is flat, and it is full of Chinatown melodrama and racistly stereotyped villains. Charles Darwin was born in , seven years after his grandfather Erasmus had died. Charles grew up during a conservative period in British and American society, shortly after the Napoleonic Wars.
Apr 09, · Evidence in Science and Religion, Part Two. By Stanley Fish April 9, Michael K. declares that “the equivalence between the methodological premises of scientific inquiry and those of religious doctrine is simply false.
But if evidence is never independent and is only evidence within the precincts of a particular theory. Western culture, sometimes equated with Western civilization, Occidental culture, the Western world, Western society, and European civilization, is a term used very broadly to refer to a heritage of social norms, ethical values, traditional customs, belief systems, political systems and specific artifacts and technologies that have some origin or association with Europe.
This special issue makes a specific contribution to this recent questioning of secularism within IR by noting and interrogating the multiple ways in which the boundaries between the religious and the political blur in contemporary politics.
We measure political ideology (very conservative, conservative, middle of the road, liberal, very liberal) using a five-point scale, with smaller numerals denoting a conservative orientation and larger ones a liberal orientation.