Download Lecture Notes 9: Evolution

Philosophy 024: Big Ideas
Prof. Robert DiSalle ([email protected])
Talbot College 408, 519-661-2111 x85763
Office Hours: Monday and Wednesday 11:30-12:30
Course Website: http://instruct.uwo.ca/philosophy/024/
What is a theory of evolution?
Species of animals and plants were not simply created in their
present forms.
Instead, their present forms are the results of gradual
modifications in previous forms, representing adaptations to
changing environments.
Not only do individual species gradually change, but also new
species come into being from previously-existing ones.
Widely differing species can therefore have common origins in
the distant past.
The variety of existing species stems from a few simple forms.
Charles Lyell (1797-1875)
Principles of Geology (1830)
Elements of Geology (1838)
The Geological Evidence of the
Antiquity of Man (1863)
Gradualism: The formation of the earth’s geological structures
has taken place by slow and gradual processes, identical to those
that can now be observed-- e.g., erosion.
This implies that the Earth has to be much older than
contemporary Christians assumed it to be.
Georges Cuvier (1769-1832)
Discourse on the revolutionary
upheavals on the surface of the
globe, and on the changes they have
produced in the animal kingdom
(1825)
Fossil remains indicate that earlier forms of animals have become
extinct: dinosaurs, mammoths, etc.
These extinctions result from extraordinary catastrophes in the
otherwise uniform history of the globe.
Jean-Baptiste Lamarck (1744-1829)
Zoological Philosophy (1809)
Natural History of Invertebrate Animals
(1815)
“Lamarckian” evolution: Species evolve by adapting to their
environments.
“First Law”: The use or disuse of physical structures by animals
causes those structures to develop or to atrophy.
“Second Law”: These structural changes are heritable.
Adaptation: Individual animals change their own forms by use
and disuse, in response to environmental conditions. Their
offspring inherit these changes.
Bishop James Usher (15811656)
Annals of the Old and New
Testament (1650)
Careful study of the chronology of the Bible, based on the
genealogies, allows us to calculate the amount of time since the
creation of Adam, and so give a date for creation:
October 26, 4004 BCE, 9:00 AM.
Charles Darwin (1809-1882)
The Voyage of the Beagle (1845)
On the Origin of Species By
Means of Natural Selection, or,
the Preservation of Favoured
Races in the Struggle for Life
(1859)
The Descent of Man, and
Selection in Relation to Sex
(1871)
The Expression of the Emotions
in Man and Animals (1872)
The Darwinian theory: Evolution by natural selection
(Blind variation and selective retention)
1. Inherited structural features of all living things are subject
to random variation.
2. Some variations will be more useful than others for
survival in a given environment, and will increase an
organism’s chance of surviving and reproducing.
3. Any environment will have limited resources to support
living populations, while organisms will tend to reproduce
beyond what those resources will support.
4. There must be a struggle for existence which will “select”
variations for survival and inheritance.
Observations supporting Darwin’s view:
1. Geological patterns reveal the earth to be much older than
previously thought, old enough for gradual processes (like
natural selection) to have tremendous effects.
2. Fossil record indicates that numerous variations have existed
and become extinct, and that many present species have
ancestral forms.
3. Artificial selection in domesticated species reveals the same
basic processes at work.
4. Different animal and plant species arise from very slight
variations on a few basic structures.
5. Differentiation reflects differences in environmental
pressures, among forms that are isolated from one another.
The “descent of man”
The ancestry of the primates:
Our nearest relations, in their current natural state…
…and after they take over…
“Beware the beast Man, for he is the
Devil's pawn. Alone among God's
primates, he kills for sport or lust or
greed. Yea, he will murder his brother to
possess his brother's land. Let him not
breed in great numbers, for he will make
a desert of his home and yours. Shun
him, for he is the harbinger of death.”
(from the Sacred Scrolls of the Apes, 29:6)
Ape sign language vocabulary
Objects:
• Apple
• Banana
• Orange
• Drink
• Eye
• Nose
• Ear
• Hat
• Baby
•
Verbs etc.
• Hurt
• Can’t
• Finished
• Hurry
• Smart
• Smell
• Hear
• Where
• Chase
Major works of sociobiology:
Alled, Emerson, Park, Park, & Schmidt: Principles of Animal
Ecology. (1949)
W.D. Hamilton: “The genetical theory of social behavior,”
Journal of Theoretical Biology, 7, 1-52.
E.O. Wilson: Sociobiology: The new synthesis (1975)
Against sociobiology:
R.C. Lewontin, S. Rose, L. Kamin: Not In Our Genes (1985)
Sociobiology: The theory that all human social structures and
interactions are explainable from an evolutionary point of view
Questions: Are social structures not merely influenced by
evolutionary biology, but also determined?
If human moral, intellectual, and social behavior is all
continuous with that of animal species, how can we maintain
the uniqueness of our species?
If human behavior is genetically determined, what possibilities
are there for the improvement of social relations and social
structures?
Can this view of human beings be reconciled with any
traditional philosophical or religious views?
Are we free?