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EVOLUTIOEVOLUTIONN
MW 1230-1:45 pmMW 1230-1:45 pm DeGRACE 312 DeGRACE 312 Attendance RequiredAttendance Required
Instructor: Instructor:
Patricia Patricia PrincehousePrincehouse
217 Rockefeller217 Rockefeller
440-478-5292440-478-5292
[email protected]@case.eduu
BIOL/ANTH/GEOL/HSTY/PHIL 225BIOL/ANTH/GEOL/HSTY/PHIL 225
Darwin and the
Nature of
Science
Lunar SocietyLunar Society
Lunar SocietyLunar Society
The Mount, ShrewsburyThe Mount, Shrewsbury
Maer HallMaer Hall
EdinburghEdinburgh“You care for nothing but
shooting, dogs, and rat-catching, and you will be a
disgrace to yourself and all
your family”
-Robt Darwin to 16-year-old Charles
EdinburghEdinburgh
Robert Grant
CambridgeCambridge
Voyage of the Beagle
Darwin ChildrenDarwin Children
Darwin ChildrenDarwin Children
Darwin ChildrenDarwin Children
Sir Richard Owen
TH Huxley
Joseph Hooker
Charles Lyell
Alfred Russel Wallace
What is Science?
The Scientific RevolutionThe Scientific Revolution
New systems: Copernican New systems: Copernican Revolution, Galileo, Descartes, Revolution, Galileo, Descartes, NewtonNewton
New reliance on experiment – New reliance on experiment – formation of scientific societies formation of scientific societies witnessing togetherwitnessing together
Separation of science from Separation of science from politics (i.e. religion & politics (i.e. religion & government)government)
Renewed interest in arguments Renewed interest in arguments for the existence of God, for the existence of God, especially the argument from especially the argument from designdesign
New systems: Copernican New systems: Copernican Revolution, Galileo, Descartes, Revolution, Galileo, Descartes, NewtonNewton
New reliance on experiment – New reliance on experiment – formation of scientific societies formation of scientific societies witnessing togetherwitnessing together
Separation of science from Separation of science from politics (i.e. religion & politics (i.e. religion & government)government)
Renewed interest in arguments Renewed interest in arguments for the existence of God, for the existence of God, especially the argument from especially the argument from designdesign
1717thth Century Science Century Science
Science since Newton:Science since Newton:
Uses only natural explanations Uses only natural explanations (methodological materialism)(methodological materialism)
Prefers reductionist explanations Prefers reductionist explanations (Ockham’s razor, (Ockham’s razor,
parsimony)parsimony) Addresses “How”, rather than “Why”Addresses “How”, rather than “Why” TestableTestable CorrectibleCorrectible ExtendableExtendable
Uses only natural explanations Uses only natural explanations (methodological materialism)(methodological materialism)
Prefers reductionist explanations Prefers reductionist explanations (Ockham’s razor, (Ockham’s razor,
parsimony)parsimony) Addresses “How”, rather than “Why”Addresses “How”, rather than “Why” TestableTestable CorrectibleCorrectible ExtendableExtendable
The 3-fold Structure of The 3-fold Structure of ScienceScience
Primary Theory (core inference)Primary Theory (core inference)
Secondary Theories (mechanisms)Secondary Theories (mechanisms)
Tertiary Theories (hypotheses/scenarios)Tertiary Theories (hypotheses/scenarios)
Primary Theory (core inference)Primary Theory (core inference)
Secondary Theories (mechanisms)Secondary Theories (mechanisms)
Tertiary Theories (hypotheses/scenarios)Tertiary Theories (hypotheses/scenarios)
The 3-fold Structure of The 3-fold Structure of ScienceScience
Core Core inferenceinference
HeliocentrisHeliocentrismm
Descent with Descent with modificationmodification
Core Core inferenceinference
HeliocentrisHeliocentrismm
Descent with Descent with modificationmodification
MechanismMechanismss
Copernicus’ Copernicus’ concentric concentric spheresspheres
Kepler’s Kepler’s lawslaws
Newton’s Newton’s lawslaws
Relativity Relativity theorytheory
String String theorytheory
MechanismMechanismss
Copernicus’ Copernicus’ concentric concentric spheresspheres
Kepler’s Kepler’s lawslaws
Newton’s Newton’s lawslaws
Relativity Relativity theorytheory
String String theorytheory
HypotheseHypotheses/s/scenariosscenarios
Halley’s Halley’s cometcomet
EclipsesEclipses Orbit of Orbit of
MercuryMercury Red shiftRed shift Hawking Hawking
radiation radiation
HypotheseHypotheses/s/scenariosscenarios
Halley’s Halley’s cometcomet
EclipsesEclipses Orbit of Orbit of
MercuryMercury Red shiftRed shift Hawking Hawking
radiation radiation
The 3-fold Structure of The 3-fold Structure of ScienceScience
Core Core inferenceinference
HeliocentrisHeliocentrismm
Descent with Descent with modificationmodification
Core Core inferenceinference
HeliocentrisHeliocentrismm
Descent with Descent with modificationmodification
MechanismMechanismss
Copernicus’ Copernicus’ concentric concentric spheresspheres
Kepler’s Kepler’s lawslaws
Newton’s Newton’s lawslaws
Relativity Relativity theorytheory
String String theorytheory
MechanismMechanismss
Copernicus’ Copernicus’ concentric concentric spheresspheres
Kepler’s Kepler’s lawslaws
Newton’s Newton’s lawslaws
Relativity Relativity theorytheory
String String theorytheory
HypotheseHypotheses/s/scenariosscenarios
Halley’s Halley’s cometcomet
EclipsesEclipses Orbit of Orbit of
MercuryMercury Red shiftRed shift Hawking Hawking
radiation radiation
HypotheseHypotheses/s/scenariosscenarios
Halley’s Halley’s cometcomet
EclipsesEclipses Orbit of Orbit of
MercuryMercury Red shiftRed shift Hawking Hawking
radiation radiation
The 3-fold Structure of The 3-fold Structure of ScienceScience
Core Core inferenceinference
HeliocentrisHeliocentrismm
Descent Descent with with modificatiomodificationn
Core Core inferenceinference
HeliocentrisHeliocentrismm
Descent Descent with with modificatiomodificationn
MechanismsMechanisms Soft InheritanceSoft Inheritance PangenesisPangenesis OrthogenesisOrthogenesis SaltationismSaltationism Natural Natural
SelectionSelection MutationMutation Genetic DriftGenetic Drift Gene FlowGene Flow GenomicsGenomics AllometryAllometry
MechanismsMechanisms Soft InheritanceSoft Inheritance PangenesisPangenesis OrthogenesisOrthogenesis SaltationismSaltationism Natural Natural
SelectionSelection MutationMutation Genetic DriftGenetic Drift Gene FlowGene Flow GenomicsGenomics AllometryAllometry
Hypotheses/ Hypotheses/ scenariosscenarios
Giraffe’s neckGiraffe’s neck Mammalian ear Mammalian ear
bonesbones Hardy-Hardy-
Weinberg Weinberg modelsmodels
DDT resistanceDDT resistance Peppered mothPeppered moth Gene familiesGene families Evo-Devo Evo-Devo
detailsdetails Lucy Lucy
ancestral…ancestral…
Hypotheses/ Hypotheses/ scenariosscenarios
Giraffe’s neckGiraffe’s neck Mammalian ear Mammalian ear
bonesbones Hardy-Hardy-
Weinberg Weinberg modelsmodels
DDT resistanceDDT resistance Peppered mothPeppered moth Gene familiesGene families Evo-Devo Evo-Devo
detailsdetails Lucy Lucy
ancestral…ancestral…
BiologyBiologyLamarck 1744-Lamarck 1744-
18291829-Characteristics -Characteristics acquired in response to acquired in response to the environment during the environment during
the lifetime of an the lifetime of an organism can be passed organism can be passed
on to its offspringon to its offspring
-Separate lineages -Separate lineages spontaneously generate spontaneously generate
& transmute through & transmute through progressively higher progressively higher levels of organizationlevels of organization
-Characteristics -Characteristics acquired in response to acquired in response to the environment during the environment during
the lifetime of an the lifetime of an organism can be passed organism can be passed
on to its offspringon to its offspring
-Separate lineages -Separate lineages spontaneously generate spontaneously generate
& transmute through & transmute through progressively higher progressively higher levels of organizationlevels of organization
Charles DarwinCharles Darwin““To my mind it accords To my mind it accords
better with what we better with what we know of the laws know of the laws
impressed on matter by impressed on matter by the Creator, that the the Creator, that the
production and production and extinction of the past extinction of the past
and present inhabitants and present inhabitants of the world should have of the world should have been due to secondary been due to secondary
causes.”causes.”
““To my mind it accords To my mind it accords better with what we better with what we
know of the laws know of the laws impressed on matter by impressed on matter by
the Creator, that the the Creator, that the production and production and
extinction of the past extinction of the past and present inhabitants and present inhabitants of the world should have of the world should have been due to secondary been due to secondary
causes.”causes.”
““On the view that species On the view that species are only strongly marked are only strongly marked and permanent varieties, and permanent varieties,
and that each species first and that each species first existed as a variety, we can existed as a variety, we can see why it is that no line of see why it is that no line of demarcation can be drawn demarcation can be drawn
between species, between species, commonly supposed to commonly supposed to have been produced by have been produced by special acts of creation, special acts of creation, and varieties which are and varieties which are acknowledged to have acknowledged to have
been produced by been produced by secondary laws.”secondary laws.”
““On the view that species On the view that species are only strongly marked are only strongly marked and permanent varieties, and permanent varieties,
and that each species first and that each species first existed as a variety, we can existed as a variety, we can see why it is that no line of see why it is that no line of demarcation can be drawn demarcation can be drawn
between species, between species, commonly supposed to commonly supposed to have been produced by have been produced by special acts of creation, special acts of creation, and varieties which are and varieties which are acknowledged to have acknowledged to have
been produced by been produced by secondary laws.”secondary laws.”
Charles DarwinCharles Darwin““ManMan with all his with all his noblenoble
qualities, with qualities, with sympathysympathy which feels for the most which feels for the most
debased, with debased, with benevolencebenevolence which extends not only to which extends not only to
other men but to the other men but to the humblest living creature, humblest living creature, with his with his god-like intellectgod-like intellect which has penetrated into which has penetrated into
the movements and the movements and constitution of the solar constitution of the solar system –with all these system –with all these
exalted powers— exalted powers— Man still Man still bears in his bodily frame bears in his bodily frame the indelible stamp of his the indelible stamp of his
lowly originslowly origins””
““ManMan with all his with all his noblenoble qualities, with qualities, with sympathysympathy which feels for the most which feels for the most
debased, with debased, with benevolencebenevolence which extends not only to which extends not only to
other men but to the other men but to the humblest living creature, humblest living creature, with his with his god-like intellectgod-like intellect which has penetrated into which has penetrated into
the movements and the movements and constitution of the solar constitution of the solar system –with all these system –with all these
exalted powers— exalted powers— Man still Man still bears in his bodily frame bears in his bodily frame the indelible stamp of his the indelible stamp of his
lowly originslowly origins””
““Descended from the Descended from the apes? apes?
My dear, we will hope My dear, we will hope it is not true. But if it is not true. But if it is, let us pray that it is, let us pray that it may not become it may not become generally known.”generally known.”
-Mrs Canon of Worchester, -Mrs Canon of Worchester,
18591859
Poets say science takes away from the beauty of the stars - mere globs of gas atoms. Nothing is 'mere'. I too can see
the stars on a desert night, and feel them. But do I see less or more? The vastness of the heavens stretches my imagination - stuck on this carousel my little eye can catch one-million-year-old light. A vast
pattern - of which I am a part... What is the pattern or the meaning or
the why? It does not do harm to the mystery to know a little more about it.
For far more marvelous is the truth than any artists of the past imagined it. Why do the poets of the present not speak of
it? What men are poets who can speak of Jupiter if he were a man, but if he is an immense spinning sphere of methane
and ammonia must be silent?
-Richard Feynman
““There is grandeur in this There is grandeur in this view of life, with its view of life, with its
several powers, having several powers, having been originally breathed been originally breathed by the Creator into a few by the Creator into a few forms or into one; and forms or into one; and that, whilst this planet that, whilst this planet has gone cycling on has gone cycling on
according to the fixed law according to the fixed law of gravity, from so simple of gravity, from so simple
a beginning endless a beginning endless forms most beautiful and forms most beautiful and
most wonderful have most wonderful have been, and are being, been, and are being,
evolved.”evolved.”
“What the Frenchman did for species,
I will do for
forms.”-Darwin, 1838 notebook
“What the Frenchman did for species,
I will do for
forms.”-Darwin, 1838 notebook
Heaven forfend me from Lamarck nonsense of a ‘tendency to progression’
C. Darwin
Heaven forfend me from Lamarck nonsense of a ‘tendency to progression’
C. Darwin
Charles Darwin Charles Darwin 1809-1882 1809-1882
Transformational Change
vs
Variational
Change
Transformational Change
vs
Variational
Change
Superfecundity Superfecundity Small-scale, Small-scale,
Copious, Copious, Undirected VariationUndirected Variation
Strong Principle of Strong Principle of HeredityHeredity
Natural Natural SelectioSelectionn
PROBLEM:PROBLEM:
Nature of Nature of Variation?Variation?
Soft vs Hard Soft vs Hard inheritanceinheritance
Fleeming Fleeming JenkinJenkin
Hard Hard inheritance:inheritance:
Blending Blending inheritanceinheritanceParticulate Particulate inheritanceinheritance
Particulate inheritanceParticulate inheritanceParticulate inheritanceParticulate inheritance
Nature of Nature of VariationVariation
Pangenesis theoryPangenesis theory
Combined hard & soft Combined hard & soft inheritanceinheritance
Expanded by DeVriesExpanded by DeVries
Pangenesis theoryPangenesis theory
Combined hard & soft Combined hard & soft inheritanceinheritance
Expanded by DeVriesExpanded by DeVries
Rediscovery of Mendel Rediscovery of Mendel 19001900
-Particulate inheritance-Particulate inheritance
-Sequestration of germ -Sequestration of germ plasm; plasm; August WeismannAugust Weismann
-Macromutation as the basis -Macromutation as the basis for for speciation; speciation; HugoHugo DeVriesDeVries
-Small-scale mutation as -Small-scale mutation as basis for gradual variation;basis for gradual variation; TH MorganTH Morgan
Nature of Nature of VariationVariation
How Mendelism How Mendelism solved solved Darwin’s Darwin’s problem:problem:
-Distinction -Distinction between phenotype between phenotype & genotype& genotype
-Discrete units of -Discrete units of inheritanceinheritance
Nature of Nature of VariationVariation
Genetic Theory
Mendelian Inheritance
X =
F1
A sexually reproducing diploid organism
Mendelian Inheritance
X =
F1
F1 X F1 =
F2
Mendelian Inheritance
X =
F1
F1 X F1 = (Aa X Aa =)F2
AA aa
Aa Aa Aa Aa
AA Aa Aa aa
Mendelian Inheritance
X =
F1Heterozygous
F1 X F1 = (Aa X Aa =) heterozygote x heterozygote
F2
25% 50% 25%
Homozygous dominant AA aa Homozygous recessive
Aa Aa Aa Aa
AA Aa Aa aa
Mendelian Inheritance XPunnett Square
A AFather’s alleles
Mother’s alleles
a
a
AA aa
Inside the boxes are the genotypes of the offspring
Aa
Aa Aa
Aa
Mendelian Inheritance XPunnett Square
A aFather’s alleles
Mother’s alleles
A
a
Aa Aa
Inside the boxes are the genotypes of the offspring
AA
aA aa
Aa
Mendelian Inheritance
XPunnett Square
A aFather’s alleles
Mother’s alleles
a
a
Aa aa
Phenotypes of the offspring:
aA
aA aa
aa
PROBLEM:PROBLEM:
Nature of Nature of Variation?Variation?
Soft vs Hard Soft vs Hard inheritanceinheritance
Fleeming Fleeming JenkinJenkin
Hard Hard inheritance:inheritance:
1919thth C: C: Blending Blending
inheritanceinheritancevs. vs. Particulate Particulate inheritanceinheritance
Mendelian Inheritance - Additive Loci
X =
X =AA aa
Aa AaAaAa
Draw a Punnett Square illustrating the genotypes of an F1 x F1 cross
Mendelian Inheritance - Additive Loci
X =Aa
AA aaAaAa
Aa
Mendelian Inheritance - Additive Loci
So, what about genes in populations?
Australian Cattle Dogs
-Clinic held at the National Specialty show
-100 dogs examined by an ophthamologist
-49 are found to be affected by Progressive Retinal Atrophy (PRA) blindness
-What is the likelihood that unaffected dogs are carriers?
-Will the disease disappear from the population?
To deal with genes in populations, we start with an
oversimplified model that preserves some important
factors for us.
Hardy-Weinberg Theoremp + q = 1
p2 + 2pq + q2 = 1
p = frequency of dominant allele (A)
q = frequency of recessive allele (a)
Cattle Dog example:
q2 = affected individuals (49/100 aa)
q = ? p =? # of non-carriers?
Assumptions of the
Hardy-Weinberg Principle
1) Mating is random
2) Infinitely large population
3) Closed breeding colony
4) No mutation
5) Equal probability of survival & reproduction
fmi Futuyma
Significance of the
Hardy-Weinberg Principle“Foundation on which almost all of the theory of
population genetics of sexually reproducing organisms --which is to say, most of the genetic theory of
evolution-- rests.” -Futuyma
-In the absence of perturbing factors, allele & genotype frequencies remain constant over
generations
-Not dependent on past history of the population (first order Markov process)
-Ratios often hold in studies of natural populatons
-Deviations often demonstrate Natural Selection at work
Fisher Haldane Dobzhansky & Morgan
Mayr
Wright
McClintock
Superfecundity Superfecundity Small-scale, Small-scale,
Copious, Copious, Undirected VariationUndirected Variation
Strong Principle of Strong Principle of HeredityHeredity
Natural Natural SelectioSelectionn
Natural Selection Natural Selection Genetic DriftGenetic Drift Gene FlowGene Flow MutationMutation
Modern Modern Synthesis:Synthesis:
4 Forces of 4 Forces of EvolutionEvolution
What’s wrong with this picture?
The Argument from The Argument from DesignDesign
Natural TheologyNatural Theology Rev William Paley, 1802 Rev William Paley, 1802
"In crossing a heath, suppose I pitched my foot against a stone and were asked how the stone came to be there, I might possibly answer that for anything I knew to the contrary it had lain there forever; nor would it, perhaps, be very easy to show the absurdity of this answer.”
"In crossing a heath, suppose I pitched my foot against a stone and were asked how the stone came to be there, I might possibly answer that for anything I knew to the contrary it had lain there forever; nor would it, perhaps, be very easy to show the absurdity of this answer.”
The Argument from DesignThe Argument from DesignNatural TheologyNatural Theology Rev William Paley, 1802 Rev William Paley, 1802
"But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place, I should hardly think of
the answer which I had before given, that for
anything I knew the watch might have always been
there.”
"But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place, I should hardly think of
the answer which I had before given, that for
anything I knew the watch might have always been
there.”
The Argument from The Argument from DesignDesign
Natural Theology Rev William Paley, 1802Natural Theology Rev William Paley, 1802
"Yet why should not this answer serve for the watch as well as for the stone? For this reason, and none other, viz.,
that when we come to inspect the watch, we perceive what we could not discover in the stone, that its several parts
were put together for a purpose."
"Yet why should not this answer serve for the watch as well as for the stone? For this reason, and none other, viz.,
that when we come to inspect the watch, we perceive what we could not discover in the stone, that its several parts
were put together for a purpose."
Argument from DesignArgument from DesignNatural Theology – Rev William Paley, Natural Theology – Rev William Paley, 18021802
Paley’s conclusion:
“when we come to
inspect the watch, we
perceive what we could not
discover in the stone, that its several parts
were put together for a
purpose..“
Paley’s conclusion:
“when we come to
inspect the watch, we
perceive what we could not
discover in the stone, that its several parts
were put together for a
purpose..“
…gets extended to the stone as well…
Mendelian Inheritance
XPunnett Square
Ee ee
You do it:
List genotypes of parents & offspring in Punnett Square
form & give the phenotypes of each
Mendelian Inheritance
Punnett Square
You do it:
What are the probable genotypes & phenotypes of the
parents of this litter?
2 Ee pups 3 ee pups
Mendelian Inheritance XPunnett Square
A aFather’s alleles
Mother’s alleles
A
a
Aa Aa
Inside the boxes are the genotypes of the offspring
AA
aA aa
Aa