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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.

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Presentation on theme: "MECHANISM of DARWINIAN NATURAL SELECTION 1. Variation exists in the population 2. Competition for survival, most animals dying before reproducing 3. Survival."— Presentation transcript:

1 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.

2 DIVERSITY EXISTS WITHIN POPULATION Homo sapiens subgraduensis

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4 DEATH IS NOT RANDOM; IT IS SELECTIVE Changes in finch beak morphology during drought of 1976/1977

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6 “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 THE MODERN SYNTHESIS

7 “Community of embryonic structure reveals community of descent.” CHARLES DARWIN ON THE ORIGIN OF SPECIES 1859 “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.”

8 Sir Richard Owen 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 Forms similar due to same function

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10 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.”

11 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 on Natural History without meeting some allusion to the Ascidians as our ancestors.”

12 THEOLOGICALLY TRAINED PASSENGERS ABOARD HMS BEAGLE Charles Darwin, 22 Cambridge University, 1830 York Minster, ca. 27 Church Missionary Society, 1830

13 EVIDENCE of COMMON DESCENT: 1. Material evidence Biblical ArcheologyPaleontology Herod’s Palace, Israel Fossil Archeopterix showing feather imprints and a reptilian body

14 EVIDENCE for COMMON DESCENT: 2. VESTIGIAL APPARATUS “Old Testament” StoriesUnused structures Would the story of Ahab been independently created in Judaism and in Christianity? Would the aortic arch have been independently created in fish and In mammals?

15 CLADOGRAM ( partial) of VERTEBRATES: DESCENT WITH MODIFICATION

16 CLADOGRAM (Partial) OF WESTERN RELIGIONS DESCENT WITH MODIFICATION

17 TWO CLADOGRAMS of WESTERN RELIGION BASED on DIFFERENT SYNAPOMORPHIES Synapomorphies of liturgy and ritual: Protestantism splits from Catholicism Synapomorphy of papal primacy: Protestantism splits from Orthodoxy

18 INDEPENDENT EVIDENCE for COMMON DESCENT: 3. Historical Records Religious textual documentationBiological genetic documentation

19 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.

20 Ernst Haeckel “ONTOGENY RECAPITULATES PHYLOGENY””HY

21 ONTOGENY PHYLOGENY ONTOGENY RECAPITULATES PHYLOGENY: 1.Correspondence 2.Terminal addition 3.Truncation

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23 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

24 “Haeckel’s “incautious generalization” has “done more to delay the progress of sound phylogeny than any other modern speculation.” -E. S. Goodrich, 1924 “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. THE DEMISE of EVOLUTIONARY MORPHOLOGY… …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

25 EXORCISING THE GHOST of ERNST HAECKEL from BIOLOGY: Stephen J. Gould, Ontogeny and Phylogeny, 1977. 1.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.

26 “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.” FRANÇOIS JACOB: EVOLUTION AS TINKERING with REGULATORY GENES in the EMBRYO

27 RICHARD B. GOLDSCHMIDT: Evolution consists of inherited changes of development Functional biology = anatomy, gene expression Development =  [Functional biology]/  t Evolution =  [Development]/  t

28 PAX6/Eyeless Expression in Insect and Mouse Eye Primordia

29 HOMOLOGOUS GENES for ANALOGOUS TRAITS Mouse Pax 6 instructs fly compound eye formation in antenna

30 HOMOLOGOUS HOX GENES: DERIVATION

31 HOMOLOGOUS HOX SEQUENCES:EXPRESSION

32 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..

33 Chick Hindlimb Duck Hindlimb BMP GremlinApoptosisNewborn HOW THE DUCK GOT ITS WEBBED FEET Merino et al., 1999. Dev. Biol. 200: 35 - 45.

34 HOW THE DUCK GOT ITS WEBBED FEET. II. Experimental Manipulation of Chick Feet Untreated Chick Hindlimb Chick Hindlimb Treated with Gremlin-Containing Bead in Interdigital Space

35 ORIGIN OF FEATHERS FROM SCALES Through Repetition of SHH-BMP Interactions (Harris, M., et al., 2002)

36 GIS MODELING of TOOTH DEVELOPMENT: FINE RESOLUTION of MORPHOGENETIC CHANGE (Jernvall et al., 2000)

37 GENE EXPRESSION PATTERNS PREDICT MORPHOLOGICAL CHANGES BETWEEN SPECIES

38 MATHEMATICAL MODELING of TOOTH EVOLUTION BY ANALYSIS of GENE EXPRESSION CHANGES (A. Salazar-Ciudad and J. Jernvall, 2002)

39 Developmental Mechanisms for Phylogeny Shigeru Kuratani et al. 2001. Phil. Trans. Roy. Soc. London B 356: 1615-1632

40 Variation within population Variation between populations Genes in adults competing for reproductive success Genes in embryonic and larval organisms building structures Survival of the fittest Arrival of the fittest Natural selection Phylogeny Population GeneticsDevelopmental Genetics A NEW EVOLUTIONARY SYNTHESIS EXPLAINING BIODIVERSITY

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