Unit-IV; Professional Sales Representative (PSR).pptx
Darwinism
1.
2.
3. Immanuel Kant
“It is absurd for human
beings ... to hope that perhaps
some day another Newton
might arise who would explain
to us, in terms of natural
laws unordered by any
intention, how even a mere
blade of grass is produced.”
Critique of Judgment, 1790
4. Daniel Dennett
“I think Darwin's idea of natural selection is the best
idea anybody ever had, ahead of Newton, ahead of
Einstein. What it does is it promises to unite the two
most disparate features of all of reality. On the one
side, purposeless matter and motion, jostling
particles; on the other side, meaning, purpose, design.
Before Darwin these were completely separate
realms. After Darwin we can see how they all fit
together into a single big picture.”
Evolution, 2001
6. Darwin’s Viewpoint
Fact
Pathway: Establishment of
genealogical relationship (“tree
thinking”) with common descent
and multiplication of species via
splitting or budding
Mechanism: Natural selection
and other mechanisms
7. T. Ryan Gregory (2008)
“Natural selection is considered by
many to be the prime component of
evolutionary theory and is the only
workable mechanism ever proposed
that is capable of accounting for the
adaptive features of organisms. At the
molecular level, nonadaptive
mechanisms are recognized as highly
significant.”
9. Evolution
“Biological (or organic) evolution is change in the
properties of populations of organisms or groups
of such populations, over the course of
generations. The development, or ontogeny, of an
individual organism is not considered evolution:
individual organisms do not evolve. The changes in
populations that are considered evolutionary are
those that are ‘heritable' via the genetic material
from one generation to the next. Biological
evolution may be slight or substantial”
Douglas J. Futuyma (1998) Evolutionary Biology
27. Natural
Selection
Economy of
Tree Thinking
Nature
Gradual Genealogical
Change Classification
Darwin
Biogeographic
Coevolution
Distribution
Sexual Selective
Selection Extinction
Deep Time
28. 1859 – First edition (1,250 copies)
1860 – Minor changes (3,000 copies)
1861 – Addition of the Historical
Sketch (2,000 copies)
1866 – (1,500 copies)
1869 – First use of Spencer’s term
“Survival of the Fittest” (2,000 copies)
1872 – Reset popular edition;
Addition of “Miscellaneous Objections
to the Theory of Natural Selection” in
response to Mivart’s Genesis of Species
and a Glossary (3,000 copies)
29. To Lyell, 1860
“I suppose ‘natural selection’ was a bad
term; but to change it now, I think,
would make confusion worse
confounded. Nor can I think of better;
‘Natural preservation’ would not imply
a preservation of particular varieties &
would seem a truism; & would not
bring man's & nature's selection under
one point of view. I can only hope by
reiterated explanations finally to make
matter clearer.”
30. “Survival of the Fittest”
"This survival of the fittest,
which I have here sought to
express in mechanical terms, is
that which Mr. Darwin has
called 'natural selection', or the
preservation of favoured races
in the struggle for life.“
Principles of Biology 1:444
(1864)
31. “Survival of the Fittest”
Suggested by Wallace and first used in 5th
edition:
“I have called this principle, by which each slight
variation, if useful, is preserved, by the term natural
selection, in order to mark its relation to man's
power of selection. But the expression often used by
Mr. Herbert Spencer, of the Survival of the Fittest, is
more accurate, and is sometimes equally
convenient.”
32. Darwin’s Big Idea
Descent with modification
through natural selection
39. Linear Growth Food Production
Exponential Growth Population Growth
Malthusian
Catastrophe
40. Thomas Malthus
“The power of population is so superior to the
power of the earth to produce subsistence for
man, that premature death must in some shape or
other visit the human race. The vices of mankind
are active and able ministers of depopulation. They
are the precursors in the great army of
destruction; and often finish the dreadful work
themselves. But should they fail in this war of
extermination, sickly seasons, epidemics, pestilence,
and plague, advance in terrific array, and sweep off
their thousands and tens of thousands. Should
success be still incomplete, gigantic inevitable
famine stalks in the rear, and with one mighty blow
levels the population with the food of the world.“
Essay on the Principle of Population, 1798
42. Fact #5
Heritability of much of this
variation
Source: animal breeders
43. Inference #2
Some of this variation is advantageous in certain
environments therefore differential survival, i.e. natural
selection, will occur.
Inference held by: Darwin, Alfred Russel Wallace, and
others
44. Inference #3
Over many generations, provided selection
pressure is maintained, evolution will occur
Inference unique to Darwin & Wallace
45. Alternatively
If there are variations in a replicating entity, and
If these are inherited, and
If one variant is more suited to some task than the
others, and
If that task directly affects survival and therefore
reproduction of the entities,
Then selection will result in evolutionary change in
the population of entities.
46.
47. Natural Selection
“A non-random difference in reproductive
output among replicating entities, often due
indirectly to differences in survival in a
particular environment, leading to an increase in
the proportion of beneficial, heritable
characteristics within a population from one
generation to the next.” (Gregory, 2009)
48. Fitness
Fitness is a measure of the reproductive output
of an organism with a particular genotype with
respect to that of other genotypes in a
particular environment.
For a trait to be evolutionarily relevant, it must
affect reproduction - it is not enough to affect
survival.
49.
50. Patrick Matthew
Appendix to Naval Timber and
Arboriculture (1831)
Claims priority in 1860 letter
to Gardeners Chronicle
51. Edward Blyth
“An Attempt to Classify the ‘Varieties’
of Animals, with Observations on the
Marked Seasonal and Other Changes
Which Naturally Take Place in Various
British Species, and Which Do Not
Constitute Varieties“ Magazine of
Natural History (1835)
Natural selection working to
preserve type and essence, i.e.
selection as a negative force.
52. William Wells
Two essays: On Upon Single Vision with Two Eyes; The Other on
Dew…and An Account of a Female of the White Race…Part of
Whose Skin Resembles That of a Negro…By the Late W.C.
Wells…with a Memoir of His Life,Written by Himself. (1818)
Some inhabitants “would be better fitted than the others to
bear the diseases of the country. This race would
consequently multiply, while the others would decrease.”
Darwin wrote “In this paper he [Wells] distinctly recognizes
the principle of natural selection, and this is the first
recognition which has been indicated…” (4th edition, 1866)
53. Unique to Darwin
Not in originating natural
selection ...
But in seeing what natural
selection was capable of doing
But where was the evidence
for natural selection?
55. Analyzing Selection
Is the population variable?
Is some of the variation among individuals
within the population heritable?
Do individuals vary in their success as
surviving or reproducing?
Are survival and reproduction non-random?
Did the population change over time?
75. Non-
Random
Random
Variation
Selection
Natural Selection is not a
Random Process
76. Level
Natural selection acts on
individuals but its consequence
occur in populations.
It does not, however, work for
“the good of the species.”
77. Predicting the Future
No need to be able to
predict long-term course of
evolution.
Evolution is analogous to a
poker tournament.
78. Darwin
“I have just been writing an
audacious little discussion, to
show that organic beings are
not perfect, only perfect
enough to struggle with their
competitors.”
Letter to J.D. Hooker, 9/11/1857
79.
80.
81. Natural Selection
Nature “cares not for mere external
appearances; she may be said to scrutinize with a
severe eye, every nerve, vessel & muscle; every
habit, instinct, shade of constitution, - the whole
machinery of the organization. There will be here
no caprice, no favoring: the good will be
preserve[d] & the bad rigidly destroyed.”
“By nature, I mean the laws ordained by God to
govern the Universe.”
82. Origin, 2nd ed.
“A celebrated author and divine has
written to me that ‘he has gradually
learnt to see that it is just as noble a
conception of the Deity to believe
that He created a few original forms
capable of self-development into
other and needful forms, as to believe
that He required a fresh act of
creation to supply the voids caused by
the action of His laws.’”
83. Letter to Asa Grey
“There seems to me too much misery in the world. I cannot
persuade myself that a beneficent and omnipotent God would
have designedly created the Ichneumonidae with the express
intention of their feeding within the living bodies of caterpillars
or that a cat should play with mice... On the other hand, I cannot
anyhow be contented to view this wonderful universe, and
especially the nature of man, and to conclude that everything is
the result of brute force. I am inclined to look at everything as
resulting from designed laws, with the details, whether good or
bad, left to the working out of what we may call chance.” (1860)
84.
85. Darwin
“The old argument of design in nature, as given by
Paley, which formerly seemed to me to me so
conclusive, fails, now that the law of natural
selection has been discovered. We can no longer
argue that, for instance, the beautiful hinge of a
bivalve shell must have been made by an intelligent
being, like the hinge of a door by a man. There
seems to be no more design in the variability of
organic beings and in the action of natural
selection, than in the course which the wind
blows. Everything in nature is the result of fixed
laws.”
86. Paley
A: X is intricate and well suited to a task T
W1: X is a product of intelligent design
W2: X is a product of random physical forces
Paley claims that the likelihood of W1 given A
exceeds that of W2, i.e. P(A|W1) >> P(A|W2)
87. Darwin
A: X may or may not be intricate or well-suited
to a task T.
W1: X is a product of intelligent design
W2: X is a product of a non-random natural
mechanism
Darwin claims that the likelihood of W2 given A
exceeds that of W1, i.e. P(A|W2) >> P(A|W1)
94. Part I – The Descent or
Origin of Man
Part II – Sexual Selection
Part III – Sexual Selection
in Relation to Man and
Conclusion
95. 1: Evidence for the Descent of
Man from Some Lower Forms
Homologous structures in man and the lower
animals
Development [Embryology]
Rudimentary structures, muscles, sense-organs,
hair, bones, reproductive organs, etc.
96. 2: On the Manner of Development
of Man from Some Lower Forms
Variability of body and mind in man
Inheritance
Laws of variation the same in man as in the
lower animals
Natural Selection
97. Man
The causes which have led to his becoming erect
Consequent changes of structure
Decrease in size of the canine teeth
Increased size and altered shape of the skull
Nakedness
Absence of a tail
Defenseless condition of man
98. Man the Biped
“As soon as some ancient member in the great series of the
Primates came to be less arboreal, owing to a change in its
manner of procuring subsistence, or to some change in the
surrounding conditions, its habitual manner of progression
would have been modified: and thus it would have been
rendered more strictly quadrupedal or bipedal. … Man alone
has become a biped; and we can, I think, partly see how he has
come to assume his erect attitude, which forms one of his
most conspicuous characters. Man could not have attained his
present dominant position in the world without the use of his
hands, which are so admirably adapted to act in obedience to
his will.”
99. 3 & 4: Comparison of the Mental
Powers of Man and the Lower
Animals
Instinct ... Emotions ... Curiosity ... Imitation ...
Memory ... Imagination ... Reason
Tools and weapons used by animals
Abstraction, Self-consciousness, Language
Sense of beauty
Belief in God, spiritual agencies, superstitions
100. The Moral Sense
Origin of sociability
Man a social animal
The importance of the judgment of the
members of the same community on conduct
Transmission of moral tendencies
101. 5: On the Development of the
Intellectual and Moral Faculties
During Primeval and Civilized Times
Advancement of the intellectual powers
through natural selection
Importance of imitation
Natural selection as affecting civilised nations
Evidence that civilised nations were once
barbarous
102. 6: On the Affinities and
Genealogy of Man
Position of man in the animal series
The natural system genealogical
Rank of man in the natural system
Birthplace and antiquity of man
Absence of fossil connecting-links
Early androgynous condition of the Vertebrata
103. 7: On the Races of Man
Arguments in favour of, and opposed to, ranking the
so-called races of man as distinct species
Monogenists and polygenists
Numerous points of resemblance in body and mind
between the most distinct races of man
Each race not descended from a single pair
Slight or no influence of natural selection
Sexual selection
118. 19 & 20: Secondary
Sexual Characters of Man
On the influence of beauty in determining the marriages of
mankind
Their ideas of beauty in women
The tendency to exaggerate each natural peculiarity
On the effects of the continued selection of women according to a
different standard of beauty in each race
On the manner of action of sexual selection with mankind
On the women in savage tribes having some power to choose their
husbands
Colour of the skin
119. 21: General Summary &
Conclusion
Main conclusion that man is descended from
some lower form
Manner of development
Genealogy of man
Intellectual and moral faculties
Sexual selection
120. “Man may be excused for feeling some pride at having risen,
though not through his own exertions, to the very summit of
the organic scale; and the fact of his having thus risen, instead
of having been aboriginally placed there, may give him hope
for a still higher destiny in the distant future. But we are not
here concerned with hopes or fears, only with the truth as
far as our reason permits us to discover it; and I have given
the evidence to the best of my ability. We must, however,
acknowledge, as it seems to me, that man with all his noble
qualities, with sympathy which feels for the most debased,
with benevolence which extends not only to other men but
to the humblest living creature, with his god-like intellect
which has penetrated into the movements and constitution
of the solar system—with all these exalted powers—Man still
bears in his bodily frame the indelible stamp of his lowly
origin.”
127. Controversies
• Is evolution always gradual? • Can complex features be
regained if lost?
• Balance between chance and
non-random mechanisms • Does “junk” DNA have a
function?
• At what levels can selection
work? • Did mammals diversify
because of the extinction of
• Are genomic duplications the dinosaurs?
common and are they
associated with major • What are the direct
evolutionary changes? ancestors of Homo sapiens?
Editor's Notes
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Not cosmogony or origin of life. \n
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~40,000 copies in 40 years (c.f. 1,000,000 in a year for Keith Richards biography),\n
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Darwin worried about losing “the analogy between nature's selection and the fanciers”.\n
Not “survival of the fittest”\n
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E. coli. with 30 minute division would weigh more than the earth in less than a week. Elephants ... 19 million in 750 years\n
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Evolution by natural selection need not occur.\n
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Fitness applies to the here-and-now, not the future.\n
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Natural selection acts on individuals but its consequence occur in populations. It does not, however, work for “the good of the species.”\n
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Natural selection is not forward looking and does not lead to perfection or necessarily progress. Adaptations need not be “perfect” in any sense.\n
