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Philosophical presuppositions of evolutionary biology FFDI Zagreb, 20-25 April 2015

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Title: Philosophical presuppositions of evolutionary biology FFDI Zagreb, 20-25 April 2015


1
Philosophical presuppositions of evolutionary
biology FFDI Zagreb, 20-25 April 2015
  1. Aims method of this lecture
  2. The received view Aristotles biology
  3. Evolutionary ideas until Darwin
  4. History of evolutionary thought from Darwin to
    the present
  5. Evolution Theory-structures and concepts
  6. Evolution between science and world-view
  7. Summary discussion
  • Prof.Dr.Dr. Winfried Löffler
  • University of Innsbruck
  • Department of Christian Philosophy
  • Karl-Rahner-Platz 1
  • A-6020 Innsbruck, Austria
  • winfried.loeffler_at_uibk.ac.at
  • www.uibk.ac.at/philtheol/loeffler

2
1. Aims and method of this lecture
  • Aims
  • Some basics about current evolutionary biology
  • Some basics about its historical backgrounds
  • Understand its peculiar theoretical status
  • Distinguish between scientific theory and its
    ideological interpretations / reductionisms
  • Misunderstandings of anti-evolutionism
  • Method historical (2-4, partly 6) to understand
    conceptual backgrounds

3
2. The received view Aristotles biology
  • 2.1 Life and Works
  • Aristotle (384-322) today usually seen as
    philosopher, but first big encyclopedist
  • Almost all scientific disciplines
  • - Physics, biology, physiology, meteorology,
    psychology,
  • - economics, politology, aesthetics / poetology
  • - ethics, rhetorics, philosophy of language,
  • - philosophy of science
  • - general philosophy (first philosophy,
    metaphysics)

4
  • Influential merits in the philosophy of science
  • - Important basic concepts (substance/accident,
    potential/actual, matter/form, efficient
    cause/final cause)
  • - Classification of the scientific disciplines
    (theoretical/practical/poietical) (episteme /
    historia / techne)
  • - Structure of scientific arguments (Prior
    Analytics, syllogism)
  • - Structure of scientific classifications
  • - Structure of an empirical science (empirical
    first sentences logical derivations from
    them) overcoming Platonism
  • Heavy influence on Western thought!!!

5
  • 2.2 Biological writings
  • Historia animalium (History of Animals) - see
    later
  • De partibus animalium (Parts of Animals)
  • De generatione animalium (Generation of Animals)
  • Smaller writings (On movement of animals, sleep
    and sleeplessness, breathing, life and death
    etc.)
  • Biggest part of his work is natural science!
  • Interestingly little interest in medicine (son
    of a healer!) and botany

6
  • 2.3 Aristotles method in biology
  • Empirical (broad sense) with speculative
    assumptions
  • Classification of phenomena plus question for
    causes (4 causes)
  • Reports of experts, own observations
  • Maybe experiments, anatomical sections (stages
    of fertilized eggs)
  • Only scarcely quantification (lengths) not
    weights, food intake etc.
  • Only scarcely ecological view (what it eats)
  • Aim Collection/classification of facts
    (historía) and research for causes

7
  • 2.3 Aristotles method in biology
  • Teleology without design
  • Natural things seen as functional units with
    functional parts
  • Teleological world-picture
  • Chief pattern of explanation final explanation,
    what is it good for?
  • Example why do animals with a lung also have a
    neck? De part.An.III,3
  • (Roughly) Bipartite lungs need some tube to
    partition the air that tube needs a certain
    length, hence the windpipe. Hence also, the
    oesophagus/jednjak. Hence, the necessity of a
    neck. (Fish dont need one). The vicinity of
    windpipe and oesophagus is technically bad and
    would cause trouble hence, nature contrived the
    epiglottis.
  • Nature as a whole is rational. Natura nihil facit
    frustra. Form follows function
  • BUT No external design plans.

8
  • 2.4 Aristotles taxonomy
  • 550 species according to morphological criteria,
    300 re-identifiable today
  • Groups and similarity observations e.g., all
    live-bearing quadrupeds have lungs and windpipes
  • Attempts to a classification of the whole range
    of animals, morphological features not always
    consistent and sometimes wrong
  • Man is included as a sub-class!

9
  • 2.4 Aristotles taxonomy
  • An example from HA IV 1, 524a3-20 The octopus
    uses its tentacles both as feet and as hands it
    draws in its food with the two that are placed
    over its mouth. The last of them, which is very
    sharp and is the only one which is whitish in
    colour and bifurcated at the tipit is made so as
    to uncoil on the rhachis side (the rhachis being
    the smooth surface of the tentacle away from the
    suckers)this one it uses in the act of
    copulation. In front of the sac and above the
    tentacles they have a hollow tube, by means of
    which they discharge from the sac any sea-water
    which may have come in while taking food into the
    mouth. The animal can move this tube to right and
    to left it also discharges its ink through it.
    It swims obliquely in the direction of the
    so-called head, stretching out its feet and by
    swimming in this way it can see forwards (since
    its eyes are on top), while its mouth is at the
    rear. So long as the animal is alive, the head is
    hard and as it were inflated. It takes hold of
    things and retains them with the underside of its
    tentacles, and the membrane between its feet is
    kept extended in its entirety. If it gets on to
    the sand, it can no longer retain its hold.

10
  • Aristotles taxonomy (roughly)
  • Animals with blood (today vertebrates)
  • Live-bearing quadrupeds
  • Egg-laying Quadrupeds
  • Birds
  • Fish
  • Cetacea (sea mammals)
  • Egg-laying footless (snakes)
  • Live-bearing footless (vipers)
  • Man
  • Animals without blood
  • Cephalopods
  • Molluscs
  • Insects
  • Crustaceans

11
  • 2.5 The stability of species
  • Fundamental for 2300 years.
  • Minimal traces of evolutionary ideas?
  • (1) Libya always produces something new (De
    gen.an. II,7)
  • crossing of animal species at waterholes
    reflection about the infertility of hybrids
  • (2) Reflection about Empedocles (5.century BC)
    mythical explanation of the origin of life
    plants first, then parts of animals, then
    animals, only the useful ones survived
  • Aristotle random combinations would not have
    survived (Phys. II, 8)
  • (3) Knowledge about variation not all animals
    conform to species, monstrosities, freak animals
    etc. (Not worrifying, just freaks of nature)

12
  • 2.6 Astonishing pioneerhoods and errors
  • Pioneerhoods
  • Sexual life of octopus
  • Opposition to preformation theory / homunculus
    theory of the sperm (until 19th century!).
    Epigenetic, step by step, formation of organs
    the important ones for the genus-membership
    first.
  • Errors
  • Bison throws feces 7m for defense
  • Women have less teeth
  • Dayfly has only 4 legs
  • Speculations
  • Parthenogenesis and other forms of reproduction
  • Procreation (in mud etc.) until Pasteur, 19th
    century!
  • Brains serve to cool blood
  • Women are incomplete men (more influence of
    katameria than of sperm)
  • Women get soul later, birth rates m/f have to do
    with winds

13
  • 3. Evolutionary ideas until Darwin
  • 3.1 Some aspects of biology after the middle ages
  • Renaissance
  • Excursions, geograph. discoveries, herbaria,
    museums
  • flourishing of anatomy (Andreas Vesalius, Fabrica
    (1543 De humani corporis fabrica libri VIII)
    public section of corpses previously unknown
    exactness descent-line apes pygmies
    (Plinius!) man)
  • 17th cent.
  • new science of nature (Bacon, Galilei)Experiments
    (planned variation of conditions, protocols)
  • New tools of observation microscope, telescope
    discovery of micro-organisms, fine structures,
    insect development
  • Physico-theology speculative preformationism
    (1695)(hot discussions 18th cent.
    (Spallanzani), end 1830!)

14
3.2 Carl von Linnés taxonomy
  • Various attempts to classifications, morphology
    comes in focus (microscopes!)
  • Tension Theory still Aristotelian (tree /
    pyramid), experienceshows multiplicity and
    similarities across branches
  • Natural history becomes a discipline of its own
  • Carl von Linné (Linnaeus), 1707-1778 Swedish
    medic and botanist
  • Reform of taxonomy, 3 merits
  • New system of plants, with classification method
    (according to number and structure of
    reproduction organs sexual system)Systema
    naturae 1735 Genera plantarum 1737 etc.
  • Binary nomenclature (instead of descriptions),
    e.g. Sambucus nigra (sambucus genus, sambucus
    nigra species)
  • Terminology for the parts of plants

15
3.2 Carl von Linnés taxonomy
  • Backgrounds of Linnés thought
  • Objective structures in nature, ideas of the
    divine creator.
  • Not Aristotelian essentialism, but rather
    Enlightenments ideal of ordering
  • Does classificatory relatedness imply anything
    about historical relatedness?
  • Does the Systema point to a relation?
  • - Linné understood it as an artificial system
    with the task of ordering/quick finding natural
    system as final project at horizon. Growing
    discontent about Linnés artificiality.
  • - Some unclear remarks about an origin of plants
  • - Controversial how firmly he believed in the
    stability of species

16
3.3 Early French speculations about evolution
  • Georges Buffon (Histoire Naturelle, 36 vols.,
    1753-1788)
  • Complexity and similarities in nature make a
    Linnéan classification impossible. And species
    is an abstractum there are individuals
  • Procreation and change, by climate etc. Related
    species might have common ancestors, maybe one.
    Earth out of a collision sun-comet.
  • Evolutionary scale/ladder instead of Linnés
    hierarchical classification
  • Evidence similar anatomy across many species
    (donkey/horse, man/ape, mans foot / horses foot
    etc.) rudimentary, useless organs
  • Indirect message EITHER God made the species by
    variation of few plans (great!), OR they have a
    common history. (Officially, the first)

17
3.3 Early French speculations about evolution
  • Georges Cuvier (1769-1832), Étienne Geoffroy
    Saint-Hilaire (1772-1844) and the Paris Academy
    Dispute 1831 Idealist versus evolutionary
    morphology?
  • Cuvier King of functional anatomy, fine
    drawings, function determines structure,
    structure allows conjecture to function.
    Reconstruction of died-out animals out of a few
    bones.
  • Four basic construction plans of animals
  • Yet firm opposition to any evolutionary change
    (cats from Egypt, )
  • Fossils are just extinct species, in
    global/regional catastrophes.
  • No intermediate forms in fossils
  • Geoffroy St.Hilaire Research in homologies (e.g.
    gill bones in fish ear bones in humans
    vertebrate is similar to inverted worm (nerves at
    back, intestinal at front). Hence, change of
    species, common ancestry.
  • Political relevance (1) not ideas of God (2)
    ...if not even nature is stable?

18
3.4 Romanticist Philosophy of Nature and
Morphology
  • Johann W. von Goethe (1749-1832)
  • morphology instead of comparative anatomy
    plants and animals represent certain ideal
    shapes/forms/con-struction plans (mostly
    superficial, restricted to outer form)
  • speculations about construction plan of a
    Urpflanze (ideal plant) which is realized in
    variants in real plants
  • Postulates that skull bones are modified rib
    bones
  • Discovers the intermaxillary bone in human
    embryos since humans represent general mammal
    plan, and all other mammals have it, it must be
    somewhere - in embryonal development!
  • Göttingen School (Carl Friedrich Kielmeyer,
    Johann Friedrich Meckel, Lorenz Oken, influenced
    by Fichte and Schelling) Recapitulation
    Development of the embryo recapitulates animals
    of lower complexity
  • Partly empirical (embryology, anatomy), partly
    philosophical formative power of nature etc.
    idealist great chain of beings

19
3.4 Romanticist Philosophy of Nature and
Morphology
  • Richard Owen (1848) Theory of archetypes
    (ideal design plans). Background similar organs
    in very different animals (moles hand
    dolphins fin have same bones!) cannot be due to
    environment.
  • Archetype of all vertebrates
  • Terminological proposal, used till today
  • Homologous organ same construction, different
    function (e.g. moles hand, dolphins fin)
  • Analogous organ different construction, same
    function (e.g. birds and butterflys wing)

20
3.5 The first evolutionary theory Lamarck 1809
  • Jean Baptiste de Lamarck (1744-1829) Philosophie
    zoologique (1809)
  • Lamarckism today inheritance of individually
    acquired characteristics, usually seen as
    overcome since Darwin partial revival today
  • First evolutionary theory a theory that how
    species change in the course of time.
  • Simple forms of life emerge constantly from
    anorganic matter, procreation hence, no common
    ancestry
  • Inner tendency to higher development,
    complexifying force le pouvoir de la vie
  • Organisms adust behaviour to environment and
    inner state
  • Use/disuse of organs leads to growth/change of
    organs (e.g. neck)
  • and that change is inherited!
  • As with Geoffroy St.Hilaire later politically
    dangerous ideas

21
3.5 The first evolutionary theory Lamarck 1809
  • Jean Baptiste de Lamarck (1744-1829) Philosophie
    zoologique (1809)
  • First Law In every animal which has not passed
    the limit of its development, a more frequent and
    continuous use of any organ gradually
    strengthens, develops and enlarges that organ,
    and gives it a power proportional to the length
    of time it has been so used while the permanent
    disuse of any organ imperceptibly weakens and
    deteriorates it, and progressively diminishes its
    functional capacity, until it finally
    disappears.
  • Second Law All the acquisitions or losses
    wrought by nature on individuals, through the
    influence of the environment in which their race
    has long been placed, and hence through the
    influence of the predominant use or permanent
    disuse of any organ all these are preserved by
    reproduction to the new individuals which arise,
    provided that the acquired modifications are
    common to both sexes, or at least to the
    individuals which produce the young.

22
3.6 Erasmus Darwin (1731-1802) and a widely
forgotten Anonymous Robert Chambers (1844)
  • Erasmus Darwin (grandfather of Charles Darwin and
    Francis Galton)
  • Speculative views about Lamarck-style evolution
  • Would it be too bold to imagine, that in the
    great length of time, since the earth began to
    exist, perhaps millions of ages before the
    commencement of the history of mankind, would it
    be too bold to imagine, that all warm-blooded
    animals have arisen from one living filament,
    which the great first cause endued with
    animality, with the power of acquiring new parts,
    attended with new propensities, directed by
    irritations, sensations, volitions, and
    associations and thus possessing the faculty of
    continuing to improve by its own inherent
    activity, and of delivering down those
    improvements by generation to its posterity,
    world without end!
  • Glimpse of natural selection
  • R. Chambers Vestiges of the Natural History of
    Creation (1844)
  • Popular science book, rather speculative, many
    errors
  • Author Robert Chambers, Scotch writer, anonymous
  • Variability of species Man descends from simpler
    forms of life
  • Popularity and (slowly starting) excitement

23
4. History of evolutionary thought from
Darwin to the present
  • 4.1 Charles Darwin (1809-1882) life and works
  • Son of a religion-skeptic physician unitarian
  • Studies briefly medicine, natural history,
    theology future parson?
  • No professional education as a scientist (biology
    not yet established!)
  • Invitation to travel on mapping-ship Beagle
    1831-36
  • Collects, studies, draws, sendssamples home
  • Initially only few doubts about stability of
    species
  • Influences
  • Charles Lyell (geologist, big changesof the
    earth surface but rejectsLamarckism species
    are createdthey die out due to external change,
    and suppression by other species)
  • Richard Owen and Romantics
  • Erasmus Darwin
  • Lamarck (via Robert E. Grant!)

24
  • Increasing doubts in Lyells biology (not in his
    geology!)
  • released domestic animals adapt quickly to new
    environment
  • two similar ostrich species in overlapping areas
    (why does the one not repress the other one?)
  • why do species dies out without change in
    environment?
  • why are died-out mammals replaced by other,
    similar ones?
  • the finches from the Galapagos islands -
    related with each other, related with animals on
    the continent, - different birds in similar
    habitats!- No clear-cut line species -
    variety

25
  • Back in Cambridge
  • Orders his findings, discusses (with Lyell, Owen,
    J. Gould (finches!))
  • Early speculations about an explanation for
    relations
  • 1837 first sketch I think, insight that
    species must be changeable
  • Darwins speculations still /- Lamarckist
    - changes/variations are always useful, since-
    adaptation to environment as an embryo,
    geograph. isolation may cause new species -
    changes are inheritable
  • 1838 reads Thomas Malthus Essay on the
    Principle of PopulationPopulations have
    tendency to grow infinitely, but limited
    resources cause concurrence and limit growth,
  • ? Darwin Selection not as embryo, but after
    birth. Theory of natural selection was /-
    finished by 1839 (diaries).

26
  • The Theory of Natural Selection
  • Random, undirected, inheritable variations
    PLUS
  • natural selection under the pressure of the
    environment, concurrence for food etc.
  • may in the long run lead to the emergence of
    adaptive (useful) change and new species.
  • I.e., variations need not be perfect anymore. Old
    idea of perfect adaptation (from natural
    theology!) abandoned. Variations need just be
    slightly better.
  • A manuscript was finished by 1842. Why not
    published? (1) Fear of scandal (Vestiges 1844!)?
    (2) Darwin had not yet a good idea for the
    ramifications / divergences in the changes.
  • After 1854 Sympatry (different species in same
    area) is more important than Allopatry (different
    species in isolated areas). Coherent with the
    facts. Reason Big areas have more ecological
    niches!

27
  • The Publication and its effects
  • 1856 Darwin presents his ideas to Lyell etc.,
    friends urge to publish
  • 1858 Alfred Russel Wallace sends a manuscript to
    Darwin, similar ideas
  • 1858 Common paper by Darwin and Wallace, Wallace
    admits priority
  • 1859 On the Origin of Species by Means of Natural
    Selection
  • Public effect
  • In England dampened by a theol. discussion
    aboutcorrect Bible interpretation 1860, and
    Vestiges
  • John Herschel (astronomer, 1792-1871)
    unscien-tific, since only statistical
  • Thomas Huxley (Darwins Bulldog) tries to
    elicitcultural discussion, free universities, no
    religion
  • Not even whole church opposes. Still excitement.
  • In France Cuvier dominates, no big interest
  • In Germany bestseller, quick translation,
    popularizedby Ernst Haeckel (materialist
    reading!)

28
  • Later Publications
  • 1871 The Descent of Man (no big scandal
    evolution of moral behavior)
  • 1872 The Expression of Emotions in Animals and
    Man
  • Works about coral reefs,
  • plant fertilisation, rainworms, etc.
  • Darwin and religion
  • 1851 Death of his daughter, loss of religious
    faith, respectful agnostic
  • 1882 Tomb in Westminster Abbey

29
  • 4.2 The Five Basic Tenets of Darwins Darwinism
    (E. Mayr)
  • Evolution species come and go through time, and
    while they exist they change. (But the real
    bearer of evolution is the individual, not the
    species!)
  • Common descent
  • Species multiply the diversification of life
    involves populations of one species diverging
    until they become separate species
  • Gradualism evolutionary change occurs through
    incremental small steps new species are not
    created suddenly.
  • Natural selection some variants change
    individuals survival reproduction probability.
  • Against Lyell species are not stable not
    perfectly adapted to environment species are not
    created quickly (Lyell was a theory of species
    sequence, not of species evolution!)
  • Against Lamarck individual changes are not
    inherited common descent

30
  • 4.3 Darwins Speculations about the biological
    fundament
  • Notabene Darwin had no idea about the place and
    nature of genetic information, laws of
    inheritance (Mendels rules etc.)
  • Theory of Pangenesis all cells produce little
    gemmulae (little buds), they gather in
    reproduction organs. In the young they mix
  • a Lamarckist remainder in Darwin!
  • Still even in 1868 (book on selective breeding of
    animals and plants). Soft inheritance, acquired
    traits are passed on.

31
  • 4.4 Some open questions in Darwin
  • Small steps or jumps? (Is mutation or selection
    the more important driving force of evolution?)
  • Why sudden speeding up of evolutionary change,
    rapid growth of species numbers in certain stages
    of earth history (Cambrian explosion etc.)
  • No real theory about inheritance, similarity and
    variability
  • Why is there life at all? No procreation (no
    conflict with Pasteur 1859) maybe 4 or 5
    original forms of life. Reference to creator more
    courtesy?
  • Speculation about the warm little pond (letter to
    Hooker 1871)
  • But if (and Oh! What a big if!) we could
    conceive in some warm little pond, with all sorts
    of ammonia and phosphoric salts, light, heat,
    electricity etc, present, that a protein compound
    was chemically formed ready to undergo still more
    complex changes...
  • Similarity to Miller-Urey experiment 1953,
    primordial soup

32
The Miller-Urey experiment
33
  • 4.5 Ernst Haeckel (1834-1919) Materialism with
    idealist traces
  • Great graphic illustrator, popularizer in Germany
  • Materialist (Darwinism as anti-religious and
    anti-conservative program!)
  • Yet some idealist remainders, idea of dynamics
    of growing complexity
  • takes on recapitulation-idea of Kielmeyer
  • Creates terms, and biogenetic fundamental law
    ontogeny repeats phylogeny
  • Evolutionary morphology similarity of gastrula
    stage? speculation to a Gastrea as common
    ancestor
  • ? tree of life
    suggests height
  • of development,
    dynamics to complexity.
    (false successful simple
    organisms,
    backward-developments)

34
  • 4.6 Francis Galton (1822-1911) Evolution becomes
    statistical
  • Cousin of Darwin, multidisciplinary scientist
    statistics, fingerprints, efficacy of prayer,
    questionnaire, blood-transfusion, eugenics
  • Experiments against Darwins gemmulae
  • semi-lamarckian speculative theory of inheritance
  • Important Separation Organism genetic
    information (stirp). Organism is just a
    representative selection from stirp, like a
    parliament
  • Inheritance becomes statistical matter, every
    parent contributes ½
  • Variation is now a matter of the population (not
    the organism, not the species!). New subject of
    evolution. Farewell to Aristotelian ideas.
  • Beginning of theoretical biology as a
    mathematicised discipline!

35
  • 4.7 August Weismann (1834-1914) The organism as
    mere vehicle of genetic information
  • Radical materialist
  • Similar to Galton, but with more empirical
    justification experiments with sea urchins
    (ježinac) germ cells are separated from the rest
    of the organism in very early stage
  • ? Separation germ cells somatic cells
  • Half-speculative theory of immortal germ
    plasm.
  • Revolutionary genetic info isthe bearer of
    variation, notthe organism only vehicle
  • Separation growth/reproduct.
  • Lamarck finally dead
  • Cf. Dawkins Selfish Gene !!

36
  • 4.8 Gregor Mendel (1822-1884) The first robust
    theory of inheritance
  • OSA monk and abbot in Brno (CZ). Experiments with
    peas etc., publication 1865 in Austrian Journal,
    no reception. Only from 1900!
  • Question in those times Does evolution go
    uniformly or in jumps?
  • Darwin (Newtons ideal! Natura non facit
    saltus!) uniformly
  • Huxley, Galton undirected, small mutations /
    variations
  • BUT such undirected small changes can cause no
    big changes, since statistics equalizes their
    effect. Statistical samples tend to average.
  • Hence, there must be other factors, Mutation must
    be more important.
  • Mendels method reduction to only few (Y/N, not
    gradual) features, quantification (counting)
  • Experiments with crossing of peas and beans
    features white/lilac flowers white/red/pink
    flowers, smooth/wrinkled seed.
  • Result Mendels rules

37
  • 4.8 Gregor Mendel (1822-1884) The first robust
    theory of inheritance
  • Mendels first law ( some more)
  • Presumptions unmixable, discrete factors of
    inheritance
  • mutation more important than selection,
    bigger jumps are possible
  • But biometry, statistics show continuous slow
    change. How can this
  • possibly be harmonized? Great crisis of
    Darwinism in early 20th century!

38
  • 4.9 The Molecular Revolution in Evolutionary
    Biology
  • End of 19th century discovery of chromosomes in
    cell nucleus
  • 1903/04 Sutton/Boveri genetic info stored in
    chromosomes
  • 1910 Johannsen Terminology Genotype (inner
    constitution, info)
  • Phenotype (appearance)
  • Genotype ? Phenotype!
  • The genotype is inherited, not directly
    the features!!
  • After 1909 Drosophila experiments (quick
    reproduction, only 4x2 chromos.)
  • Beginning of localisation of genetic info on
    chromosomes (chemistry still unknown till 1953!)
  • Insights - some features controlled by more
    than one gene
  • - there are interactions between genes
  • - one gene can influence more than one feature
  • HENCE 11-matching genes ? features false
    since early 20th century!
  • genetic blueprint metaphor likewise wrong
    (still it is around)

39
  • 4.9 The Molecular Revolution in Evolutionary
    Biology
  • 1953 Watson/Crick Discovery of double-helix
    structure of desoxyribonucleic acid (DNA)
  • Since mid-1960 Mechanisms of gene expression
    (DNA RNA proteine synthesis) begin to be
    clarified
  • Human genome project 1990-2003
  • Mind the correct way of speaking
  • Sequencing the genome.
  • (Not decoding the genetic code
  • fallback to blueprint model!)

40
  • 4.10 The Modern Synthesis (1920s, 1930s
    onwards)
  • Darwinism had no undisturbed victorious career
    no uniform development of post-Darwinist biology.
    Especially Mendels genetic discoveries caused
    worries quick changes, either/or are possible.
    Mutation is more important!
  • Darwins intuition small, incremental steps,
    selection is more important
  • The great crisis of Darwinism / Eclipse of
    Darwinism (J.Huxley 1942)
  • Late 19th/ early 20th century all 5 tenets of
    Darwin come under doubt, many biologists step
    back to older theories, partly speculative.
  • Extension of population genetics (Ronald Fisher,
    Sewall Wright, John B. S. Haldane) Complex
    mathematical models to combine Mendel Darwin
  • Some ideas from population genetics
  • On genotype level Mendelian jumps, on phenotype
    level only small Darwinian changes since
    features often depend on many genes!
  • Population (not individuals) as the unit of
    evolution, statistics equalize in some
    individuals Mendelian jumps, in population slow
    Darwinian shift
  • The smaller a population, the easier are big
    jumps possible.

41
  • 4.10 The Modern Synthesis
  • Theodosius Dobzhansky, Ernst Mayr and others
  • The Modern Synthesis, Synthetic Biology of
    Evolution
  • connects Darwinian core idea (stepwise
    evolution, selection)
  • Mendelian genetics
  • Population genetics
  • Biometry
  • Microbiology
  • Biochemistry
  • Behavioral science
  • Paleontology
  • Geology
  • etc.

42
  • 4.11 Some special ingredients of the Modern
    Synthesis
  • Genetic drift / bottleneck / founder effect
  • (A non-adaptive effect, against
    pan-selectionism!)
  • Punctuated equilibrium (Eldredge/Gould)
  • Various explanations of stages of stasis
  • and rapid evolutionary change allopatric
  • origin of species (related with genetic drift)
  • Neutralism (Kimura) many big changes in DNA come
    and go,
  • without being tested by selection, neutral
    changes possible

43
  • 4.11 Some special ingredients of the Modern
    Synthesis
  • Cooperation between genes Regulator genes,
    governing the expression of other genes, genetic
    switches. E.g. Hox genes, regulate development
    of legs, antennas etc.? mutations in such genes
    may have big effects!
  • ? Evo-Devo (Evolutionary developmental
    biology)
  • similarities in the genotype are astonishingly
    high across species, but
  • phenotypes differ dramatically!
  • Hence genes in themselves are not so important
  • Hence difference must lie in the expression of
    the genes, development of the organism, regulator
    genes etc.
  • Evolutionary biology in the past took adult
    organism (and populations out of them) as subject
    to natural selection,
  • EvoDevo takes the whole process/cycle of
    development of an organism as the subject of
    natural selection.

44
  • 5. Evolution Theory-structures and concepts
  • 5.1 Theory-structure of EB
  • Physics, chemistry etc. law-like explanations,
    able to prediction
  • false predictions a part of falsification
  • Evolutionary biology admits of (almost) no
    interesting predictions
  • Herschel un-scientific, mere statistical
    relations
  • (young) Popper unfalsifiable tenets like the
    survival of the fittest, circular.
  • Partial answer
  • (1) Parts of explanations admit of predictions
    (cell level etc.)
  • Some few experiments with bacteria admit of
    prediction even of direction of evolution on
    macro-level in lactose solution, bacteria with
    mutation develop genes to process lactose
  • (2) Why decreeing that all scientific
    explanation must resemble physics?

45
  • 5.2 Is EB a science?
  • Not a science like physics combination of
    natural historical disc.
  • Rather a scientific research program, uniting
    many disciplines
  • Criteria by Philip Kitcher (The Advancement of
    Science, 1993)
  • A scientific practice
  • Investigates an accepted domain of objects
  • Investigates accepted problems and questions
  • Has a non-natural technical terminology
  • Has commonly shared convictions at its basis
  • Applies accepted means and methods
  • Has accepted standards on aim and success of the
    investigations
  • Has accepted standards how to accepts results
    from other sciences
  • Is part of a social network
  • Evolution biology scores excellently under most
    criteria!

46
  • 5.3 The bearers / objects of evolution
  • Individuals / organisms?
  • Species?
  • Populations?
  • Genetic information?
  • Life-cycles? ?different metaphysical views
    on objects of biology!
  • 5.4 What are the traits / characteristics /
    features tested by evolution?
  • a) only bodily features (shape, food
    tolerances, ) or also behavior? Dawkins
    the extended phenotype (including behavior) is
    being tested!
  • b) Adaptive traits (with a success story)
    maladaptive traits by-products
  • c) Is every feature adaptive? ? Panselectionism.
    (But what is a feature??)
  • d) Beware of a frequent misunderstanding
    concerning success story of trait - not
    the trait makes its success story (the trait is
    not there from beginning!) - rather ex
    post, we see a success story of the trait and its
    previous traits (evolution does
    bricolage with available traits!). No trait
    essentialism

47
  • 5.5 Misunderstandings
  • Survival of the fittest - Can be incremental
    need not be perfect
  • - need not be the strongest/biggest/
  • Struggle for life - is not intra-population
    struggle
  • - need not be fight with similar species
  • - just general struggle with the ecological
    conditions food, climate, safety,
    nesting-places
  • 5.6 Genes ( an unsettled debate! by the
    genes is no explanation!)
  • place on the chromosome? surely to imprecise
  • sequence on the DNA (concrete gene)? things
    are more complicated are regulated
    /switched-on genes really genes?
    Coding/non-coding DNA? Some DNA sequences are
    read more than once, some corres-pond to more
    than one proteine? Beginning/end sometimes
    unclear,
  • whatever makes a difference in fitness
    (abstract, functional gene)? may come close to
    antirealism concerning gene genetic info.

48
  • 6. Evolution between science and world-view
  • 6.1 Overview
  • SCIENCE
  • Darwins (historical) Darwinism
  • Darwinism Synthetic theory of Evolution (1940
    onwards)
  • Current EB (New synthesis, EvoDevo, )
  • CONTROVERSIAL
  • Pan-Selectionism
  • Sociobiology
  • Cultural Evolution, Memetics
  • NON-SCIENCE
  • Social Darwinism
  • Pop-Darwinist Slogans

49
  • 6.2 Pan-Selectionism
  • Sometimes also strict neo-Darwinism,
    Darwinist orthodoxy
  • (Terminology seems not to be entirely fixed)
  • Thesis natural selection is the driving force of
    evolution every feature has an evolutionary
    success story behind it
  • Tendency to a deterministic account of the world
    and the human being evolutionary successful
    features are /- hard-wired, that includes also
    our mind, our reactions, etc.
  • Critical evaluation empirically unplausible in
    the light of modern genetics
  • Ironically a remainder of old perfect
    adaptation ideas (natural theology)

50
  • 6.3 Sociobiology
  • Extension of evolutionary explanations also to
    our behavior, moral beliefs etc.
  • First visions already in Darwin moral tribes
    might be more successful
  • Example1 why is altruism evolutionary
    successful?
  • At first glimpse not at all. Risk your life,
    lose eating-time etc.
  • Example whistle-blowing birds
  • But kin-selection / group-selection (E.O. Wilson,
    Sociobiology 1975) brothers/sisters have 50
    same genetic info, cousins 25, ? saving the
    life of, e.g., 5 cousins by whistle-blowing (and
    sacrifying own life!) increases the survival of
    own genetic info! 125 - 100 25
  • Example 2 why are moral norms evolutionary
    useful?An economic way to secure cooperation of
    group members, internal/mental control instead of
    expensive external forces
  • Critical evaluation Empirically unclear
    evidence
  • Manifold cultural shapings of behavior, limit
    natural/cultural unclear
  • Sociobiol. is no exclusive explanation (altruism
    is nothing but xy)

51
  • 6.4 Cultural evolution, memetics
  • 1976 Richard Dawkins, The Selfish Gene (and in
    later books)
  • 1995 Daniel Dennett, Darwins Dangerous Idea
  • Basic idea behavioral and cultural practices are
    passed on by imitation, they can be seen as items
    of cultural information memes. Such memes
    undergo competition and selection, some do
    propagate, some do not
  • Examples termite-poking of chimpanzee tribes
    language, use of fire, wheel, wall-graffiti,
    literary figures, cooking recipes, religion,
    product designs, business ideas
  • Critical evaluation Suggestive examples
  • But huge differences between genes and memes-
    genes mutate at random, memes often
    intentionally- genes from distant branches of
    evolution non mixable, memes are- memes are
    inherited in Lamarckist ways, individual
    inventionsIn sum misleading metaphor,
    parasitic on good image of biology. Even
    dangerous when mixed with ideas of neo-liberalism

52
  • 6.5 Social Darwinism
  • Label from 19th century, roots rather in Thomas
    Malthus and Herbert Spencer than in Darwin.
  • Basic ideas (1) Evolutionary explains (and
    predicts) social facts (2) Evolutionary biology
    is not only descriptive (what is
    the case?), but also normative (what should
    we do?)
  • (3) Evolution is progress
  • (4) There are good and bad genetic
    information-bits (for that progress!)
  • (5) Progress should not be retarded, bad
    genetic info should be suppressed
    (handicapped, lower races, )
  • Usually rivalry of all against all (people in a
    society, nations / nations, ), misunderstanding
    of struggle for life
  • Notabene NS ideology was not closely connected
    with Darwin. Racism!

53
  • 6.5 Social Darwinism
  • Critical evaluation
  • (1) Is/ought fallacy, description / normativity
    fallacy / genetic fallacy
  • (2) Biological basisof Social Darwinism is
    dubious and rather Lamarckist Evolution is
    progress. But progress/regress are not
    biological categories at all
  • (3) It depends on the environment which forms are
    progressive / more successful (small and
    undemanding animals might be most
    successful!)I.e., social Darwinism rests on some
    aesthetic ideals of what is healthy, strong,
    progressive etc.
  • (4) Even if we could create a perfect natural
    world, this does not guarantee a pleasant,
    humane culture. False genetic determinism, nature
    does not determine culture.

54
  • 6.6 Some pop-Darwinist slogans
  • Nature and Evolution are nothing else but a
    huge process of chance and random
  • BIOLOGICALLY FALSE, at least selection is not
    random.
  • Darwinism means that mutation and natural
    selection explain every feature.
  • BIOLOGICALLY MOST PROBABLY FALSE, only most
    narrow-minded pan-selectionists would deny other
    evolutionary effects
  • Cosmic evolution There is one big
    evolutionary process from Big Bang to human
    culture.
  • CONCEPTUAL NONSENSE. (1) Not every
    agglomeration and development process (as in the
    early universe) is also an evolution process.
    There is no multiplication, mutation,
    inheritance, and selection for protons, galaxies,
    stars etc. Over-extension of a biological
    metaphor. (2) On cultural evolution, see 6.4.



55
  • 6.6 Some pop-Darwinist slogans
  • Society and economy work according to
    evolutionary laws.
  • SEE 6.4 above!
  • Science (like biology) consists of falsifiable
    claims only, world-views are irrational and
    subjective.
  • FALSE FROM THE VIEWPOINT OF PHIL. OF SCIENCE.
    (1) Too narrow concept of science
  • (2) Background assumptions are even at work in
    the sciences see Kuhns paradigms, Lakatos
    hard cores of research programs. Border to
    world-views fuzzy world-views contain rational
    structures, can be more/less plausible, and
    rationally discussable. See Popper there are
    genuine philosophical problems, beyond science.

56
  • 6.7 Biology and Religion On Creationism,
    Intelligent Design etc.
  • A bit of history
  • USA a country of small religious groups, partly
    literal reading of the Bible
  • About one half of the population has serious
    doubts about evolution
  • Empirical fundament unclear spots in evolution,
    cosmic fine tuning
  • Spectrum
  • Short-time (Young-earth) creationism 6
    days, about 6000 yrs ago
  • Long-time creationism (special creationism)
    successive intervention
  • Intelligent Design design-plans, to solve
    irreducible complexity
  • Theistic Evolution (Vatican II God as 1st
    cause carries 2nd causes)
  • Deism
  • Atheism, metaphysical naturalism
  • Wealthy think-tanks, www.discovery.org etc.,
    disinformation, wedge

57
  • 6.7 Biology and Religion On Creationism,
    Intelligent Design etc.
  • Objections to ID
  • Unclear ontology of design plan, at odds with
    usual scientific ontology
  • Selective evidence, focused on explanatory gaps
    and failures of EB
  • Some irreducible complexities are reducible
    regulator-genes etc. may explain complexities
  • Filling-the-gap-theology every new biological
    discovery makes God more irrelevant, theology on
    constant retreat
  • ID proves only world-constructor (demiurg), not
    creator
  • Why a single God behind the 1000s of appearances
    of ID? Tacit background theology smuggled in.
  • Problem of evil radicalized source of bad
    design, senseless design?
  • In sum neither necessary nor fruitful for the
    Christian.
  • (Due!) criticism of reductionism and ideology
    should not turn into (undue) pseudo-scientific
    blends of theology and biology.

58
  • 7. Summary
  • Aristotle inaugurated a vision of biology with
    the species in focus, and a teleological view at
    the world yet, without external design.
  • The raise of modern evolutionary thought began
    before Darwin and was based on empirical findings
    as well as on speculative ideas. Darwin and
    Wallace developed the first coherent, large-scope
    theory with a broad empirical basis (still with
    many blind spots).
  • The basic ideas of Darwin are still topical in
    the core of current EB. However, EB cant be
    reduced to mutation and selection.
  • Current EB is a research program with many open
    questions, especially about the impact of natural
    selection. Central concepts like gene admit of
    different readings.
  • This is one reason why EB has a strong affinity
    to be reduced to an ideology, more than other
    sciences. Another reason is the wide scope of EB,
    from the explanation of shape to behavior.
  • ID is a dubious blend of theology and biology
    which appears neither necessary nor useful for
    the theologian.

59
  • 8. Repetition questions
  • How does Aristotles conception of science differ
    from Platos?
  • Name 4 of Aristotles biological writings and
    their (rough) content.
  • How does Aristotles method in biology
    resemble/differ from today?
  • What type of discipline is an episteme, what a
    historia?
  • Why did we describe Aristotles biology as
    teleology without design?
  • Sketch Empedocless explanation of the origins of
    life and Aristotles counter-argument.
  • Aristotles doctrine of the stability of species
    (what is it?) is said to have prevented
    evolutionary ideas for centuries. But are there
    any traces of variability of species in
    Aristotle?
  • How did Aristotle describe the development of an
    embryo?
  • What is preformationism?
  • What is procreationism?
  • What was new about Linnés taxonomy system? What
    are its limits? Was he an Aristotelian?

60
  • What other inventions did he make which are still
    important for biology?
  • Sketch Buffons anti-Linnéan position.
  • What was the Paris Academy Dispute 1831
    ultimately about? (Dont just say idealist
    versus evolutionary morphology, but explain the
    issue!)
  • What are homologous organs, what are
    analogous ones?
  • Explain some of the basic intuitions of
    Romanticist biologists, and name some important
    persons.
  • Why can we say that Lamarck presented the first
    evolution theory? Only under what conditions
    should something be called an evolution theory?
  • What does crucially distinguish Lamarckism from
    standard evolutionary biology?
  • How did Lamarck explain the change of organisms
    in the course of time?
  • Name some thinkers and researchers who influenced
    Darwin!
  • How did Malthus change Darwins thought?
  • Why is Darwins theory of natural selection no
    theory of perfect adaptation?
  • What is sympatric, what allopatric origin of new
    species?
  • How did Ernst Mayr summarize classical Darwinism?

61
  • Sketch Darwins gemmulae theory. What was it
    good for, what was it supposed to explain?
  • List some open problems in Darwin.
  • Why are Haeckels tree-diagrams suggestive in a
    false direction?
  • What does his biogenetic fundamental law say?
  • Describe the separation of genetic information
    from the organism in Galton, Weismann and
    Dawkins. In what are stirp, germ plasm and
    selfish gene similar?
  • What new point of view dis Galton bring into
    biology? Why does this bring a turn away from
    Aristotelian ideas?
  • Why was the Weismann barrier seen as a
    death-blow to Lamarckism?
  • Why did Mendels discoveries shake the Darwinism
    of his time? What was the worrisome problem?
  • Sketch some main steps in the discovery of
    genetic information.
  • Why is we can today decode the genetic code a
    problematic way of speaking?
  • Why can population genetics perhaps unite
    Darwinist and Mendelian ideas?
  • What does pan-selectionism claim?

62
  • Why is the (empirically backed!) idea of genetic
    drift an argument against pan-selectionism?
  • Try to describe some basic ideas of EvoDevo. Why
    is EvoDevo a remedy against the misconception of
    a genetic blueprint?
  • How do evolutionary explanations differ from
    physical explanations?
  • Why has evolutionary biology a special structure,
    different from other natural sciences?
  • What units/bearers of evolution were proposed in
    the history of biology?
  • Why is it misguided to say feature F had an
    evolutionary success story?
  • What did Darwin mean by struggle for life?
  • Sketch different notions of a gene.
  • How would socio-biologists explain that altruism
    is sometimes evolutionary successful, even if it
    goes to sacrificing ones life?
  • What is a meme? Why is cultural evolution a
    non-starter?
  • Describe the mistakes of Social Darwinism.
  • Why is Intelligent Design not a wise choice for
    theologians?
  •  
  • GOOD LUCK FOR THE EXAM!
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