Archive for December, 2010
Since 1859, the search for Darwin’s “slight, successive” accumulated actions of natural selection has become a driving scientific and societal phenomenon. In 1872, the British Parliament commissioned the HMS Challenger for first international exploration to discover the “missing links” resulting from natural selection.
Like the HMS Challenger experience, evidence for “slight, successive” evolutionary changes continues to be an elusive pursuit—in the fossil record and now in molecular biology. Darwin’s dilemma deepens with the latest evidence from the Denisova caves in Russia.
Of all the alleged facts in The Origin of Species, for Charles Darwin embryology stands out as the most important “fact”. In a letter to Asa Gray in September 1860, Darwin wrote – “embryology is to me by far the strongest single class of facts in favor” of the theory.
Darwin was influenced by German embryologist Ernst Haeckel, who coined the now-famous phrase “ontogeny recapitulates phylogeny”. In other words, in the embryo the ontology (development) of the new offspring retraces (recapitulates) all stages representing its alleged evolutionary ancestors (phylogeny) from the microbe to man. Haeckel called the theory the “biogenetic law”.
In The Origin of Species, Darwin gave credit for this theory to Haeckel. “Professor Haeckel in his “Generelle Morphologie” and in [other] works has recently brought his great knowledge and abilities to bear on what he calls phylogeny, or the lines of descent of all organic beings. In drawing up the several series he trusts chiefly to embryological characters [to establish evolutionary sequences].”
According to Haeckel, in the embryo is a silent movie of our alleged ancestral history—evolution in action. Through his polished and widely publicized drawings, Haeckel attempted to show that all embryos are identical in the earliest stages followed by progressive “slight, successive” changes of increasing differential complexity—the alleged retracing of evolution.
Much has happened since 1859, however. This week, ScienceDaily featured an article entitled “Similarities in the Embryonic Development of Various Animal Species Are Also Found at Molecular Level”. The article was referring two research papers published in the journal Nature, December. 9, 2010 by the Max Planck Institute that challenge the basic tenets of Haeckel’s theory of “ontogeny recapitulates phylogeny”.
Charles Darwin in a letter Joseph D. Hooker in February 1871 speculated that life might have originated in “some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, &c., present, that a proteine compound was chemically formed ready to undergo still more complex changes”. The search for the origin of life continues.
Felisa Wolfe-Simon (shown on the left), supported by NASA’s Exobiology and Evolutionary Biology (Exo/Evo) Program and the NASA Astrobiology Institute, is a researcher working with programs to determining the evolution of genes, metabolic pathways, and microbial species on Earth in order to understand the potential for life on other worlds. Continue Reading
Lyle challenged the premise that the history of the Earth has experienced supernatural and catastrophes events, including Noah’s flood as documented in Genesis. Ironically, Lyell was a graduate of Exeter College, a Catholic institution.
The frontispiece image illustrates the main point of the book: that evidence of the forces of geological change that have been shaping Earth for millennia is observable today—”the present is the key to the past”. The temple columns, with their high-water marks were the evidence Lyell used to propose that the sea levels had changed gradually several times. Continue Reading