Evolutionary of Primates

Ch. Zollikofer ([email protected]) M. Ponce de León ([email protected]) organization/web resources

• lecture: Mo, 15:00-16:45 • final exam: Mo, 19. Dec. 15:00-16:00

• www.aim.uzh.ch/morpho/wiki/Teaching/EvoDevoPrimates – course scripts (pwd: EvoDevo207) – links and papers • OLAT: BIO207/Downland/Scripts – course scripts basic questions

• what is the developmental background of the evolutionary diversification of primates, esp. hominoids and hominids? – what are the developmental mechanisms of evolutionary novelty/change? – what are the functional consequences of developmental novelty/change? example: chimp versus human contents

• historical roots of evo-devo • basic concepts of evo-devo • specific topics – head – teeth – brain – somatic development – life history – evo-devo of fossil hominins historical roots

development, and the problem of variability Conrad Gesnerus (1516-1565)

• Historia animalium: – organismic diversity – between mythology, creation and biology J. J. Scheuchzer (1672-1733)

• Lithographia Helvetica: – fossils: “Naturspiele”, “Ueberbleibsel der Sintflut” – divine and natural laws

Homo diluvii testis mechanisms of organismic development

• preformation – , , ...

• epigenesis – , 1651 “de generatione animalium” – C.F. Wolff (1734-94) modern

(N. Hartsoecker 1695) “pre-evolutionary” biology

• J.-B. de Lamarck (1744-1829): – philosophie zoologique • “rational morphologists”: – J.W. Goethe (1749-1832) – E. G. St. Hilaire (1772-1844) – G. Cuvier (1796-1832) – R. Owen (1804-1892) • reductionist approach: – search for “archetypes” (body plans, Baupläne): – common principles of • organismic organization • taxonomic organization • development Richard Owen (1804-1892)

• homology • homoplasy “pre-evolutionary” biology

• causes of morphological variability? – are fixed entities (cf. Mendelian !) – variability is a side effect (deviations from the archetype) • causes of temporal change? – cataclysms, “catastrophisme” – (spontaneous) emergence of new species? Mendel and the invariance of species

• Versuche über Pflanzen-Hybriden (1865):

“..., dass der Species feste Grenzen gesteckt sind, über welche hinaus sie sich nicht zu ändern vermag. Wenn auch dieser Ansicht eine bedingungslose Geltung nicht zuerkannt werden kann, ...” Darwin/Wallace (1809-1882/1823-1913)

• 1859: switch of paradigm: – variability is the source of temporal change of species and the emergence of new species – common principles of organization reflect common descent – dynamic (genealogical) arguments replace static (structural) arguments (1834-1919)

• ontogeny and phylogeny: connecting evolutionary and developmental time scales – Biogenetisches Grundgesetz: • ontogeny recapitulates phylogeny • theory of terminal addition Haeckel (1874): Anthropogenie oder Entwickelungsgeschichte des Menschen

Richardson, M. K. et al. (1998): Haeckel, embryos and evolution. Science 280, 983–986 (1792-1876)

• von Baer’s law: – general features appear before special features – embryos are not identical to early evolutionary forms August Weismann (1834-1904)

• germ plasm theory: – continuity of germ cell lines – discontinuity of somatic cell lines • falsification of pangenesis theory (Darwin) Hans Spemann Hilde Mangold

• 1920s: experimental embryology – induction and differentiation – morphogenetic agents – mechanics of development – developmental pathways, constraints

• 2nd half of 20th century: – embryology splits into cell biology and molecular biology Th. Dobzhansky, E. Mayr and the Modern Synthesis

• a population-genetic theory of evolution – phenotypic variability expresses genotypic variability – phenotypic variability is random – proximate versus ultimate causes: p.c. are not relevant for understanding evolution the “dogma of Modern Synthesis”

• what are the causes of genetic and phenetic variability? – mutations • what is the pattern of genetic and phenetic variability? – random • what are the causes of taxonomic structure? – and problems of the Modern Synthesis

• Spandrels/Panglossianism • link between development and evolution? • link between genotype and phenotype? • link between genotypic and phenotypic of variability? • causes and patterns of phenotypic variability? S.J. Gould versus R. Dawkins

• structuralism – organismic structure results from develpmental constraints

versus

• adaptationism (neo-) – organismic structure results from adaptive constraints Monsieur Pangloss and adaptationism

„Remarquez bien que les nez ont été faits pour porter des lunettes, aussi avons- nous des lunettes.“

Voltaire, Candide rethinking evo-devo

• D.W. Thompson – On Growth and Form: physical laws of biological form and form variability • C. H. Waddington – epigenetic landscapes: developmental reaction norms • S. J. Gould – Ontogeny and Phylogeny: role of developmental modification for evolution • Turing, Wolfram, Kauffman, ... – chemical and mathematical models of morphogenesis Waddington’s epigenetic landscapes

Slack, JMW (2002). Conrad Hal Waddington: the last biologist? Nat. Rev. Gen. 3, 889-895 rethinking evo-devo

• relationship between genotype and phenotype: – non-linear, web-like • phenotypic effects of genetic change: – largely unpredictable • phenotypic variability: – not due to natural selection, but to developmental program variability – non-random • taxonomic order: – not due to natural selection, but to developmental constraints organismic “structure”: basic evo-devo questions

• how does it originate during ontogeny? • how is it constrained? • how is it conserved through time? • how does it change in time?

• are processes; their structure is a result of processes example 1: Raup’s shell morphospace

distance D translation T whorl expansion W Raup's shell morphospace Raup's shell morphospace

• 3-parameter theoretical morphospace: – whorl expansion rate – translation rate (pitch) – whorl distance from axis • "empty" regions • constraints – selection/function? – evolutionary history? – development?

Raup, D.M. (1966). Geometric analysis of shell coiling: general problems. J. Paleo. 40, 1178-1190 example 2: hominoid diversity

hominids

Sahelanthropus morphospace of cranial shape

Australo- pithecines Gorilla

fossil Homo great apes Chimp

Bonobo

Zollikofer et al., 2005 example 2: hominoid diversity

hominids morphospace of cranial shape

?

great apes merging structuralist and adaptationist programs

• establish links between: – genotype and phenotype (genomics - proteomics - ... morphology); “post-genomic era” – developmental reaction norms and evolutionary novelty – present/past diversity, environmental constraints and developmental constraints • understand organisms as processes – function of ontogeny? – adaptation of ontogenetic programs?