Evolution - BiosystematicsThere is grandeur in this view of life, with itsThere is grandeur in this view of life, with itsseveral powers, having been originally breathedseveral powers, having been originally breathedinto a few forms or into one; and that, whilstinto a few forms or into one; and that, whilstthis planet has gone cycling on according to thethis planet has gone cycling on according to thefixed law of gravity, from so simple a beginningfixed law of gravity, from so simple a beginningendless forms most beautiful and mostendless forms most beautiful and mostwonderful have been, and are being, evolved.wonderful have been, and are being, evolved.[conclusion of [conclusion of Origin of SpeciesOrigin of Species]]. . . from so simple a beginning endless forms. . . from so simple a beginning endless formsmost beautiful and most wonderful have been,most beautiful and most wonderful have been,and are being, evolved.and are being, evolved.Thomas Burnet (1681)Thomas Burnet (1681)••Typical pre-18th century view of Earth and its changesTypical pre-18th century view of Earth and its changesThomas Burnet (1681)Thomas Burnet (1681)““no truth concerning the Naturalno truth concerning the NaturalWorld can be an enemy of religion;World can be an enemy of religion;for Truth cannot be an enemy tofor Truth cannot be an enemy toTruth, God is not divided againstTruth, God is not divided againsthimselfhimself””••Typical pre-18th century view of Earth and its changesTypical pre-18th century view of Earth and its changesJeanJean Baptiste Lamarck Baptiste Lamarck (1744-1829) (1744-1829)••Early evolutionary thought - Early evolutionary thought - ““ladder thinkingladder thinking””LamarckLamarck’’s s ““LadderLadder””••Continuum between physicalContinuum between physicaland biological world (afterand biological world (afterAristotle)Aristotle)••Scalae NaturaeScalae Naturae ( (““Ladder ofLadder ofLifeLife”” or or ““Great Chain of BeingGreat Chain of Being””))GodAngelsDemonsManAnimalsPlantsMineralsNon-beingRealm ofBECOMINGRealm ofBEINGBeing••Life progresses upwardLife progresses upward due to an due to aninternal drive towards perfection =internal drive towards perfection =transmutationtransmutation••Why are primitive organisms stillWhy are primitive organisms stillaround?around?––Spontaneous generationSpontaneous generation of new life of new lifeconstantlyconstantly••Mechanism of change?Mechanism of change?––Inheritance of acquired charactersInheritance of acquired charactersLamarckLamarck’’s s ““LadderLadder””LamarckLamarck’’s (1809) fourteen level s (1809) fourteen level ladder hierarchyladder hierarchyLamarckLamarck’’s s ““LadderLadder””••There is There is no oneno onelinear ladderlinear ladder(Georges(Georges Cuvier Cuvier))LamarckLamarck’’s later s later ““TreeTree””••LamarckLamarck (reluctantly) influenced (reluctantly) influencedbyby Cuvier Cuvier’’s argumentss arguments••Appended table in 1809 (Appended table in 1809 (volvol. 2. 2ofof Philosophie ZoologiquePhilosophie Zoologique))showing showing two linestwo lines of ofspontaneous generation withspontaneous generation withsubsequent branchingsubsequent branchingLamarckLamarck’’s 1809s 1809 appendum appendumLamarckLamarck’’s later s later ““TreeTree””••By 1815By 1815 Lamarck Lamarck announced his announced hisconversion to branching as theconversion to branching as thefundamental pattern offundamental pattern of““evolutionevolution””••““In its production of the differentIn its production of the differentanimals, animals, nature has notnature has notfashioned a single and simplefashioned a single and simpleseriesseries””LamarckLamarck’’s 1815 s 1815 ““treetree””LamarckLamarck’’s later s later ““TreeTree””••His last book (His last book (Analytical SystemAnalytical Systemof Positive Knowledge of Manof Positive Knowledge of Man,,1820) has gone largely1820) has gone largelyunnoticedunnoticed““Reptiles come necessarily after fishes.Reptiles come necessarily after fishes.They build They build a branching sequencea branching sequence, with, withone branch leading from turtles toone branch leading from turtles toplatypusesplatypuses to the diverse groups of to the diverse groups ofbirds, while the other via lizards towardbirds, while the other via lizards towardthe mammals. The the mammals. The birds then build abirds then build arichly varied branching seriesrichly varied branching series, with one, with onebranch ending in birds of prey.branch ending in birds of prey.””S.J. Gould, 1999S.J. Gould, 1999Robert Chambers (1844)Robert Chambers (1844)••The only pre-Darwin The only pre-Darwin ““evolutionevolution”” book that English book that Englishspeakers could read in 1840s and 1850sspeakers could read in 1840s and 1850sRobert Chambers (1844)Robert Chambers (1844)••Darwin later stated that Darwin later stated that VestigesVestiges –– although flawed although flawed –– set the set thestage for acceptance of his ideas of evolution set down instage for acceptance of his ideas of evolution set down inhis book his book Origin of Species Origin of Species in 1859in 1859••Immediate criticism on oneImmediate criticism on onemain point: main point: denial of specialdenial of specialcreation for each speciescreation for each speciesRobert Chambers (1844)Robert Chambers (1844)••BosanquetBosanquet (Biblical scholar) (Biblical scholar)published his rebuttal the nextpublished his rebuttal the nextyear and based it primarily on theyear and based it primarily on theissue of issue of special creationspecial creationRobert Chambers (1844)Robert Chambers (1844)Charles Darwin (1859)Charles Darwin (1859)only figure in only figure in Origin of Species - Origin of Species - illustration ofillustration of‘‘descent with modificationdescent with modification’’DarwinDarwin’’s s ““Tree-thinkingTree-thinking””The three main claims ofThe three main claims ofDarwinian evolutionDarwinian evolution••Living species are related by Living species are related by common ancestrycommon ancestry[descent][descent]••Change through time occurs not at the organismChange through time occurs not at the organismbut at the but at the population levelpopulation level••The main cause of adaptive evolution is The main