On the Origin of Species 852

On the Origin of Species

Understanding Charles Darwin’s
Famous Study

Bertolino--Origin of Species--Mosaic 852 1

What is Evolution?
• Evolution under the influence of natural selection leads to adaptive
improvement. Evolution, whether under the influence of natural
selection or not, leads to divergence and diversity. From a single ultimate
ancestor, many hundreds of millions of separate species have, at one time
or another, evolved. the process whereby one species splits into two is
called speciation. Subsequent divergence leads to ever wider separation
of taxonomic units – genera, families, orders, classes, etc. Even creatures
as different as, say, snails and monkeys, are derived from ancestors who
originally diverged from a single species in a speciation event.
• http://www.bbc.co.uk/education/darwin/leghist/dawkins.htm

• This paragraph, taken from an article by Richard Dawkins, can give us a
sense of what The Origin of Species did for modern science and ultimately,
the modern conception of man’s origin.


Charles Darwin

Life and Times
• fifth child of a wealthy, liberal English family with a long line of
famous ancestors
• graduated 1825 from the elite school at Shrewsbury
• entered University of Edinburgh to study medicine
• entered the University of Cambridge with the goal to become a
priest in the Church of England, however, he became interested in
nature, geology and biology and learned all about scientific study,
observation, data recording and analysis from his professors Adam
Sedgwick and John Stevens Henslow,
• After graduating from Cambridge in 1831, Darwin hired aboard the
British survey ship HMS Beagle in order to participate in a
scientific expedition around the world.


Darwin…
• The expedition, expected to take two years, took five years .The ship traveled
around the world (see maps on next slides)
• During the expedition, Darwin made discoveries about
– Geology and how the earth was formed (uniformitarism vs.
catastrophism)
– Biology and Biogeography (natural variation and adaptation)
– The Origin of Species and Anthropology (survival of the fittest, evolution)
• After returning in 1836, Darwin spent almost 20 years analyzing the data he
collected and writing up the results.
• He lived outside London, was married to Emma Wedgewood and had 10
children. Because of his wealthy background, he was able to study without the
necessity to earn a living.
• He first announced his theories in 1858 and published the On the Origin of
Species in 1859. His book was an immediate success.


Darwin…
Darwin spent the final 23 years of his life expanding on
different aspects of problems raised in the Origin. His later
books-including
- The Variation of Animals and Plants
Under Domestication (1868)
- The Descent of Man (1871)
- The Expression of the Emotions in
Animals and Man (1872)
• The importance of his work was well recognized by his
contemporaries, yet many of his ideas were heavily
contested and some debates continue into the present.
• He died in Downe, Kent, on April 19, 1882 and was buried
in Westminster Abbey


Darwin’s Influences
• Aristotle: Plato believed that Ideas or Forms constituted matter; physical objects came
from a permanent essence in thought that determined their existence. Aristotle saw
matter as the fulfillment of a physical idea—the form constitutes the concept. He looked
at the world as it was--Aristotle saw ultimate reality in physical objects, knowable through
experience. Objects, including organisms, were composed of a potential, their matter, and of
a reality, their form; thus, a block of marble -- matter -- has the potential to assume whatever
form a sculptor gives it, and a seed or embryo has the potential to grow into a living plant or
animal form. In living creatures, the form was identified with the soul; plants had the lowest
kinds of souls, animals had higher souls which could feel, and humans alone had rational,
reasoning souls. In turn, animals could be classified by their way of life, their actions, or, most
importantly, by their parts.

• Great Chain of Being—the order of things. The world has a spiritual hierarchy that
extends from the lowest physical creature to the supernatural (amoebas to the
archangels with intellectual abilities that are superior to our own.) This theory
illustrated that God’s omnipotence included other planets that possibly had spiritual
beings—it was a continuum of life that never ended, like a ladder into the heavens from
the earth.

Other Influences
• Jean Baptiste Lamark (1744-1829)—all forms of life have arisen through a long
process of continuous adjustment. Nature had an instinctive sense for improvement;
each living creature, plant and animal, moved to a higher stage of development. The
environment proved to be a factor in these movements toward change: the dictates
of nature caused animals, plants to modify their features in order to survive. These
same changes would move on to the subsequent generation.

• Thomas Malthus ((1766-1834)—Populations tend to increase geometrically
while food supplies increase arithmetically. Malthus was an economist who
discriminated against any social welfare: he connected population growth with
food abundance and he believed that this correlation was natural in order to
maintain population growth from exceeding the natural sustenance that our
world could give. Disease, famine and human conflict are modes to control
population in accordance with nature. If we continue to use social reforms to
help the poor, we will interfere with nature’s plan to maintain human survival
as God intended it to be.
• Darwin disagreed with this laizzez-faire cruelty, yet it gave him the basis of his
theory of natural selection.


Voyage of the Beagle—Various
Aspects:Full View


Travels Through South America:
Atlantic Side


Brazil—Upper South America


Argentina


Darwin’s Discovery in Argentina
Darwin was very curious about the geology of the river valley.
The walls of the valley had the same layers of shells he had seen
many times before. It was during this expedition that Darwin
theorized that the cliffs of the river valley, and indeed the Andes
Mountains themselves, had been slowly raising above sea level.
The evidence for a planet in a state of constant flux was
becoming stronger and stronger. While today we take this for
granted, in Darwin's day the notion of changes on a planetary
scale went against the view that god's creation was perfect and
thus change was Bertolino--Origin of Species--Mosaic 852
unnecessary. 13

The Beagle Travels Past Cape Horn
Darwin made some of his most important
discoveries on the Pacific side of South
America.

To Mocha Island off The Mainland of Chile
On March 4th the Beagle entered the Harbor of Talcuhano near Concepcion.
Darwin was dropped off at the island of Quiriquina. Here he explored around
the coastline of the island and found several expanses of fresh marine rock
that had risen a few feet above sea level due to an earthquake. Darwin also
noticed raised shell beds on the cliffs above and became very excited about
this find, as it was direct evidence that the Andes mountains, and indeed all of
South America, may be very slowly raising above the ocean.
These discoveries added much weight to Charles Lyell's theory that land masses
rose up in tiny increments over extremely long periods of time. Darwin accepted
the idea that the earth must be extremely old. The next day Darwin went by
ship to Talcuhano Harbor. From the shore he rode by horse to the town of
Concepcion.

Another Discovery Along the
Mainland of Chile
• Darwin head back, on March 29th, to Chile via the Uspallata Pass, just
north of Mendoza. He spent the next few days at Villa Vicencio and
explored the geology of the area. He was shocked to find that the local
mountains were mainly composed of submarine lava flows, and these
at 6,000 feet above sea level and 700 miles from the coastline! Eleven
trees had been fossilized and 30-40 had turned into calcareous spar.
Most of the trees were a few feet tall and snapped off at the top and 3-5
feet in circumference, and were coniferous.
• To make matters even more confusing for Darwin, he also found huge
numbers of petrified trees in the same area. His mind was reeling with
questions: how long ago was this land under the ocean, how did the trees
end up under water so they would become petrified? Darwin spent the
next few days thinking about how Charles Lyell would interpret what he
was seeing and also began developing some geological theories of his
own.


Up the Andes Mountain Range and To
The Galapagos


Darwin’s Discovery:
Some of the specimens Darwin collected from the Galapagos:
One buzzard, two owls, three flycatchers, three species of mockingbirds,
one species of finch, one swallow, one dove, 13 species of finches (Darwin
remarked how fascinated he was by the beak gradations, but the variation
of finches confused Darwin a great deal), one turtle, one tortoise, four
lizards (sea and land iguanas and two other types), four snakes, and very
few insects.
These specimens helped Darwin come up with theories of reproduction: why
do finches have such a variety of beaks? Do they breed different beaks to
determine their rate of survival?

Variation of Finch Beaks and the Geological Table


The Beagle Travels to the South Pacific,
Visiting New Zealand, Tahiti and Australia.

New discoveries are made.


Darwin’s Discovery:
Darwin went with a guide and two horses on a 120 mile inland trip to
Bathurst, New South Wales. Darwin commented on the scant
vegetation, and contrasted it with the tropical forests of South
America. Along the way Darwin made observations on the local
wildlife and was very astonished by the creatures he saw (especially
the odd-looking platypus). He surmised there must have been a
separate act of creation just for these odd creatures.
Again, he mused on the role of reproduction and adaptation: how do
living things change in different climates? Do they take on new traits
(adapt) in order to survive the climate changes or do many die off while
other life begins to thrive?

The Beagle
Darwin spent 5 years on this ship and his discoveries radically changed
his views on the origin of organic life.


Questions to Consider
1.What point does Darwin prove with his ideas on Variation under
Domestication? Which examples does he use?

2.What is the difference between domestic and natural variation?

3.What is the underlying process of explaining natural variation as
opposed to controlled variation? (See “Variation under Domestication”
and compare it to “Struggle for Existence” in the text.)

4.What examples of adaptation does Darwin use? How can this theory
be used to explain the fact that the dinosaurs became extinct?

5.What are the long term implications of natural selection for the
development of humanity?


Summary of First Four Chapters
Ch. 1 Variations under Domestication:
Darwin uses examples such as horses, dogs, or pigeons, to prove that
with careful selection, consequent breeding it is possible to bring out
intended characteristics.
Ch.2 Variations under Nature:
Darwin discusses the possibility that selection also occurs in nature,
just slower than with domestic breeding. The issue here is adaptation to
the corresponding natural environment that causes this amazing
variability. Yet, one question remained: Why do these variations occur?
Ch.3 The Struggle for Existence:
Day to day existence is a constant struggle that ensures that selection
will occur. Those less able to adapt and thereby survive will reproduce
and pass on the traits that made survival possible. In this way, nature
ensures that only the fittest survive the process he terms…


Natural Selection—Chapter 4
Ch. 4 Natural Selection.
Natural selection explains, why certain species survive and thrive,
others, less able to adapt, become extinct. Natural selection,
however, also supports the notion of a slow process of adoption and
survival. The result is a successive evolution and improvement of a
species, and not a sudden creation of each individual species.
The intriguing thought behind this is that there is an ongoing process
of evolution from one particular ancestor to a variety of succeeding
subspecies. There is additionally, a variety of subspecies that have
not succeeded (reproduced over time) and eventually they become
extinct.
• Question: What factors determine which species will survive and
which one will die off?
• Question: How do you understand the word “selection”?
• Question: How do you understand the word “natural”?


Ideas from Chapter 1
• Immutability vs. Variation under Nature—Does the world change?
• Darwin’s observations of nature suggest that the earth is very old.
Geologists in Darwin’s lifetime (Charles Lyell) had studied fossils and
worked on theories that different fossils represent different time periods in
earth’s history. Creationists called this a part of God’s plan.
• Darwin considered the sea cliffs on the Galapagos Islands: they suggested
that the water level gradually receded from a previous point. He found
well-formed shells imbedded in the cliff—he hypothesized that the cliff had
once been under water. The change couldn’t have been cataclysmic or else
the shells would not have been intact.

• Darwin discussed the intent of animal breeders who use unconscious
selection, a method of matching like traits in order to produce a certain
kind of animal. Consider how certain race horses are used as studs—similar
idea. These ideas come from “Variation Under Domestication.”


Adaptation: A Part of Natural
Selection
• Variation among plants and animals—does the reproduction of like
traits occur in nature?

• Darwin theorized that living creatures unconscious adapt in order to
survive. Adaptive traits are reproduced; non-adaptive ones decrease in
number over time.
• He looked at domesticated pigeons as an example. He couldn’t believe that
man bred seven to eight species of the domesticated pigeon; he concluded
that they came from a wild state that was eventually tamed. Later he wrote
that “changed conditions of life are of the highest importance in causing
variability, both by acting directly on the organization, and indirectly by
affecting the reproductive system.” Variation, he believed, “is governed by
unknown laws of which correlate growth….something…may be attributed
to the …conditions of life. Some…may be attributed to the increased use
of disused parts.”


The Struggle For Existence
Darwin understood this as both the individual struggle and the success of reproduction. He
called it “ the doctrine of Malthus applied with manifold force to the whole animal and
vegetable kingdoms….although some species may now be increasing…all cannot do so, for
the world will not hold them.”
• Members of a variety with adaptive traits live longer and have more time to reproduce, thus
adaptive traits become dominant in a particular environment.

Modification of a variety occurs when there is a change that results in better environmental
adaptation. Beak, web sizes may alter; certain plants may develop a different way to seed—
these are adaptations that modify the species. These traits continue as the creature reproduces
to insure survival. This entire process over time is called natural selection.

If man can cause unconscious selection through breeding, then why cannot nature do the
same? He argues that “natural selection acts only by the preservation and accumulation of
small inherited modifications, each profitable to the preserved being”. He believes that the
elements of natural selection: physical alterations, reproduction, and intercrossing take place
over long periods of time. All of these are a response to the demands of the environment.


Chapter 6: Difficulties of Theory
• This chapter only appeared in the 6th edition to
answer various doubts about the theory.
• He focused on natural selection, breaking it down
from species to species.
• He relied heavily on the samples he had found
from his journey on the Beagle.
• He discussed creatures, like the flying lemur—
falsely classified as a bat. The flank membrane
gave him reason to think that the lemur once had
a longer membrane that connected fingers and
forearms, disused through reproduction over time.

Chapter 7: Instinct
• The closest Darwin comes to defining the term
instinct is the following: “An action, which
we ourselves (humans) should require
experience to enable us to perform, when
performed by an animal, more respectively
by a young one, without any experience, and
when performed by many individuals in the
same way, without their knowing for what
purpose it is performed, is usually said to be
instinctive.” (paragraph 2 of Chapter 7)

To illustrate what he calls instinct in a “state of nature”, Darwin uses
bees—hive bees. Then he focuses on ants in great detail.
• Why are the worker ants rendered sterile? What modifications within
reproduction are they instinctively not supposed to pass on? Darwin sees
this as natural selection.
• Darwin looks at time: he writes: “As natural selection acts only by the
accumulation of slight modifications of structure or instinct, each
profitable to the individual under its conditions of life, it may
reasonably be asked, how a long and graduated succession of modified
architectural instincts, all tending toward the present plan of
construction, could have profited the progenitors?” (Chapter 7, section on
bees) In this sentence, Darwin is referring to the hive bee, but it is also
applicable to all species in their struggle for survival.

• Evolution postulates that new species are descended from
Chapter 9: On the earlier species, which changed into those new species over
periods of time. Evolution thus predicts that there were
Imperfection of the organisms which existed at these transitional stages turning
from one form into another. It is possible that evidence of
Geological Record these evolutionary transformations may be found in the
fossil record. This was noted by Darwin: “The number of
intermediate varieties, which have formerly existed on the
earth, [must] be truly enormous.”( paragraph 1 of Chapter
9)
• However, Darwin recognized that the fossil record did not
contain fossils of these "intermediate" forms of life and he
struggled to understand the reason:
• “We continually forget how large the world is, compared
with the area over which our geological formations have
been carefully examined; we forget that groups of species
may elsewhere have long existed and have slowly
multiplied before they invaded the ancient archipelagoes
of Europe and the United States. We do not make due
allowance for the enormous intervals of time which have
probably elapsed between our consecutive formations—
longer perhaps…that the time required for …each
formation.” (Chapter 9)

• In other words, Darwin staunchly believed that his
theory was correct, so he took issue with the
presentation of the geological record (fossils, timeline) as
an incomplete process that missed certain evidence of
life—species that developed and declined without
leaving a record of their existence.


The Gradual Change or Adaptation of
Species
Darwin was convinced the transition of species took
place. He suggested a process—look at the circled
shapes above and imagine them to be reproductive traits
that are discarded or strengthened over a long period of
time.

Chapter 11—Geographical
Distribution
• In this chapter, Darwin explores species migration. Why do pigeons survive in
multiple climates, while elephants are only found in warm climates? Why do some
species seem to travel and form subspecies while others remain exclusive to a
particular territory?
• Darwin writes: “I believe…in no law of necessary development. As the variability
of each species is an independent property and will be taken advantage of by
natural selection, so the degree of modification in different species will be no
uniform (standard) quality.” (Chapter 11)
• So the process of natural selection allows for migration-in other words, it is part of
the adaptation process for some species to seek out other environments; it is also
crucial for other species to remain in the place of their origin—this insures the
survival of the species and subspecies in both cases.
• Some of this is intuitive—think about instinct from chapter 7. Some of this is
also reliant on how a particular species travels—birds fly, fish swim, so it can
be easier for them to travel than certain mammals. However, certain birds and
fish cannot survive in different climates. So the process of natural selection
determines both the impulse to migrate and the necessary adaption to various
climates. The animals that cannot survive elsewhere will stay put.


Drawings of possible
migrations

The first images shows various species
that Darwin found in the Galapagos
during his voyage on the Beagle.

The second drawing shows a
hypothesis of Darwin’s theory of
species evolution through the process
of migration. Macroevolution covers
the movement/adaptation of animal
and plant life in their entirety

Microevolution shows the changes
over time within each species. For
example, are tortoises the original
species for what we call the common
turtle? If so, how did turtles end up in
the Northern Hemisphere? Are they a
subspecies of the Pacific tortoise? How
did the turtle evolve as a subspecies
and why does it live in cooler
climates?.


More on Migration
• Darwin writes: “If, for instance, a number of species, which stand in
direct competition with each other, migrate in a body into a new and
isolated country, there will be little liable to modification, for neither
migration or isolation can do anything. These principles come into
play only by bringing new organisms into new relations with
each other (the life forms that exist in the place of migration—my
note).”
• Darwin writes: “It is obvious that the several the several species of
the same genus, though inhabiting the most different quarters of the
world, must originally have proceeded from the same source as
they have descended from the same progenitor.”
• Darwin came to these conclusions largely from his study of
finches and pigeons. (see slide 19)


Conclusion of Text—Chapter 14
• John Whitfield, a science writer from England wrote the following
on Chapter 14: “As its title suggests, the fourteenth and final chapter
of the origin, 'Recapitulation and Conclusion', mostly restates things
that Darwin has already said, often several times.”
• “This relentless piling, sorting and re-arranging of evidence can
make Darwin seem a little OCD, like an intellectual version of Wall-
E. But he also knows that beneath all the case studies, there's a
logical core to evolution by natural selection, even if he can't put it
in an equation. Darwin brackets this chapter by showing that, if you
accept the most basic evidence the living world puts before your
eyes, evolution follows as surely as a lever moves a stone.”
• “And as the reader lowers the book, it points him or her outward.
Evolution isn't an abstraction, it's not just something you see on the
Galapagos Islands. It's going on right now, all around you. This is
how you see the world now.”


As Darwin Puts It:
• “Thus, from the war of nature, from famine and
death, the most exalted object which we are
capable of conceiving, namely, the production of
the higher animals, directly follows. “
• “There is grandeur in this view of life, with its
several powers, having been originally breathed
into a few forms or into one; and that, whilst this
planet has gone cycling on according to the fixed
law of gravity, from so simple a beginning endless
forms most beautiful and most wonderful have
been, and are being, evolved. “(Chapter 14)


Epilogue
Introduction to Social Darwinism(present at
the APS exhibit)
Marx was greatly influenced by Darwin and he respected his ideas. He wanted
to dedicate his major work, Das Kapital,to him, but Darwin refused the honor.
Marx misunderstood the theory of natural selection as a method to
manipulate the means (mode) of production so that the exchange of
commodities would benefit workers in a communist society.
Marx wanted to recreate the entire economic model (capitalism) into
communism: he thought that natural selection would work as a force to
improve man as a species, so it was logical to assume that the next step for
man’s survival would be to throw off the chains of wage slavery as a necessary
step in his evolution. Darwin saw this as a misreading of his theory.
One result of Darwin’s Origin of Species was Social Darwinism. This idea
came from Herbert Spencer’s term, survival of the fittest. Darwin used this
term to name the process of natural selection in nature as living creatures
struggle for their existence. These beings develop variations that grant them an
advantage as they compete for food and shelter. Darwin saw this as an
unconscious tool of nature.

What is Social Darwinism?
• Social Darwinism: literally a process of elimination in a capitalist society. The
strong adapt to the rigors of the free market system and the poor decline. Society
must coexist as a unit, similar to the creatures in a jungle, and each person takes on
traits to ensure his survival. Ultimately, it promotes the group that has the dominant
traits that lead it to take over their environment. This theory became the basis for
some of the most heinous acts in history: it was used to justify ruthless business
practices of the industrial tycoons, the conquest of the Americas, the genocide of
Native Americans, Imperialism in countries like India, Vietnam, and much of
Africa. Perhaps the most odious example is Nazism:

• Ernst Haeckel, a 19th German biologist, used the Origin of Species to assert his
vision of the German people as a superior race. He believed that nations had to
fight to survive as organisms did or they would perish. Society must be ruled by the
same laws of competition and aggression that are found in nature. Individual life
was unimportant. The Jews, Gypsies, Africans and Slavic people were inferior.
Heinrich Himmler admired Haeckel and formed an Aryan youth movement in 1918.

• (His work was featured in the APS exhibit along with Eugenics, an offshoot of
Darwin’s research into heredity and genetics. Note: these terms came AFTER
Darwin’s death.) Bertolino--Origin of Species--Mosaic 852 44

Design For Darwin Birthday Cake


On the Origin of Species 852

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