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MECHANISM of DARWINIAN NATURAL SELECTION. 1. Variation exists in the population 2. Competition for survival, most animals dying before reproducing 3. Survival of those most fit for the environment 4. Offspring are from the survivors 5. Offspring inherit the genes that made their parents
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MECHANISM of DARWINIAN NATURAL SELECTION 1. Variation exists in the population 2. Competition for survival, most animals dying before reproducing 3. Survival of those most fit for the environment 4. Offspring are from the survivors 5. Offspring inherit the genes that made their parents fit for the environment.
DIVERSITY EXISTS WITHIN POPULATION Homo sapiens subgraduensis
DEATH IS NOT RANDOM; IT IS SELECTIVE Changes in finch beak morphology during drought of 1976/1977
THE MODERN SYNTHESIS “Evolution is a change in the genetic composition of populations. The study of the mechanisms of evolution falls within the province of population genetics.” --Theodosius Dobzhansky. 1951
CHARLES DARWIN ON THE ORIGIN OF SPECIES 1859 “Community of embryonic structure reveals community of descent.” “Embryology rises greatly in interest, when we look at the embryo as a picture, more or less obscured, of the progenitor, either in its class or larval state, of all the members of the same great class.”
HOMOLOGY “The same organ in all its varieties of form” Serial Homology Derived forms within the same organism Special Homology Derived forms between different species Versus Analogy Sir Richard Owen Forms similar due to same function
KARL ERNST von BAER: “The general features of a large group of animals appear earlier in development than do the specialized features of a smaller group…The early embryo is never like a lower animal, but only like its early embryo.”
DARWIN (1874): “Thus, if we may rely on embryology, ever the safest guide in classification, it seems that we have at last gained a clue to the source whence the Vertebrata were derived.” AGGASIZ (1874): “One could hardly open a scientific Journal or any popular essay onNatural History without meeting some allusion to the Ascidians as our ancestors.”
THEOLOGICALLY TRAINED PASSENGERS ABOARD HMS BEAGLE Charles Darwin, 22 Cambridge University, 1830 York Minster, ca. 27 Church Missionary Society, 1830
EVIDENCE of COMMON DESCENT: 1. Material evidence Biblical Archeology Paleontology Fossil Archeopterix showing feather imprints and a reptilian body Herod’s Palace, Israel
EVIDENCE for COMMON DESCENT: 2. VESTIGIAL APPARATUS “Old Testament” Stories Unused structures Would the aortic archhave been independently created in fish and In mammals? Would the story of Ahab been independently created in Judaism and in Christianity?
CLADOGRAM ( partial) of VERTEBRATES: DESCENT WITH MODIFICATION
CLADOGRAM (Partial) OF WESTERN RELIGIONS DESCENT WITH MODIFICATION
TWO CLADOGRAMS of WESTERN RELIGION BASED on DIFFERENT SYNAPOMORPHIES Synapomorphy of papal primacy: Protestantism splits from Orthodoxy Synapomorphies of liturgy and ritual: Protestantism splits from Catholicism
INDEPENDENT EVIDENCE for COMMON DESCENT: 3. Historical Records Religious textual documentation Biological genetic documentation
GENETIC EVIDENCE for DESCENT WTH MODIFICATION MOLECULAR SYNAPOMORPHIES Phylogenetic tree made from interspersed DNA elements. Four transposon insertions, at loci 4-7, define a clade of whales and hippos.
Ernst Haeckel “ONTOGENY RECAPITULATES PHYLOGENY””HY
ONTOGENY RECAPITULATES PHYLOGENY: Correspondence Terminal addition Truncation ONTOGENY PHYLOGENY
Evolution is based on Haeckel’s diagrams about as much as Christianity is based on Titian’s paintings. HAECKEL’S CRIMES WERE FAR WORSE: “The lower races…are physiologically nearer the mammals--apes and dogs--than to the civilized European. We must, therefore, assign a totally different value to their lives.” “He (Jesus) is generally regarded as being purely Jewish. Yet the characteristics Which distinguish his high and noble personality and which give distinct impress to his religion are certainly not Semitical. They are the features of the higher Arian race.” --The Riddle of the World, 1899
THE DEMISE of EVOLUTIONARY MORPHOLOGY… “It is difficult, even if possible, to say whether the differences or the resemblances have a greater zoological value (because we have no clearly defined standard of zoological value).” -A. Sedgwick, 1894. “Haeckel’s “incautious generalization” has “done more to delay the progress of sound phylogeny than any other modern speculation.” -E. S. Goodrich, 1924 …AND THE EXODUS TO GENETICS "Morphology having been explored in its minutest corners, we turned elsewhere...The geneticist is the successor of the morphologist." -W. Bateson, 1894
EXORCISING THE GHOST of ERNST HAECKEL from BIOLOGY: Stephen J. Gould, Ontogeny and Phylogeny, 1977. Confusion of von Baer with Haeckel. Von Baer established commonality of embryonic forms. Haeckel believed that embryos of later organisms past through adult stages of primitive organisms. 2. Darwin used von Baer, not Haeckel. However, Haeckel became popular and eclipsed the Darwinian/von Baer view.
FRANÇOIS JACOB: EVOLUTION AS TINKERING with REGULATORY GENES in the EMBRYO “Small changes modifying the distribution in time and space of the same structures are sufficient to affect deeply the form, the functioning, and the behavior of the final product--the adult animal. It is always a matter of using the same elements, of adjusting them here or there, of arranging various combinations to produce new objects of increasing complexity. It is always a matter of tinkering.”
RICHARD B. GOLDSCHMIDT: Evolution consists of inherited changes of development Functional biology = anatomy, gene expression Development =d[Functional biology]/dt Evolution = d[Development]/dt
PAX6/Eyeless Expression in Insect and Mouse Eye Primordia
HOMOLOGOUS GENES for ANALOGOUS TRAITS Mouse Pax 6 instructs fly compound eye formation in antenna
MUTATIONS IN REGULATORY GENES CAN GIVE THE PROTEINS NEW PROPERTIES: UBX ACQUIRES THE ABILITY to REPRESS DISTAL-LESS in the INSECT CLADE R. Galant and S. B. Carroll, 2002. Nature 415:910. Ronschaugen, M. et al. 2002. Nature 415: 914. .
HOW THE DUCK GOT ITS WEBBED FEET Merino et al., 1999. Dev. Biol. 200: 35 - 45. Chick Hindlimb Duck Hindlimb Gremlin Apoptosis Newborn BMP
HOW THE DUCK GOT ITS WEBBED FEET. II. Experimental Manipulation of Chick Feet Chick Hindlimb Treated with Gremlin-Containing Bead in Interdigital Space Untreated Chick Hindlimb
ORIGIN OF FEATHERS FROM SCALES Through Repetition of SHH-BMP Interactions (Harris, M., et al., 2002)
GIS MODELING of TOOTH DEVELOPMENT: FINE RESOLUTION of MORPHOGENETIC CHANGE (Jernvall et al., 2000)
GENE EXPRESSION PATTERNS PREDICT MORPHOLOGICAL CHANGES BETWEEN SPECIES
MATHEMATICAL MODELING of TOOTH EVOLUTION BY ANALYSIS of GENE EXPRESSION CHANGES (A. Salazar-Ciudad and J. Jernvall, 2002)
Developmental Mechanisms for Phylogeny Shigeru Kuratani et al. 2001. Phil. Trans. Roy. Soc. London B 356: 1615-1632
Population Genetics Developmental Genetics Variation within population Variation between populations Genes in adults competing for reproductive success Genes in embryonic and larval organisms building structures Arrival of the fittest Survival of the fittest Natural selection Phylogeny A NEW EVOLUTIONARY SYNTHESIS EXPLAINING BIODIVERSITY