evolution n mw 1230-1:45 pm n degrace 312 n attendance required instructor: patricia princehouse 217...

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

evolution@case.edevolution@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