Transcript Explorations of the Universe

Evolution and the Notion of
Progress
“Of course, long before you mature,
most of you will be eaten.”
“The picture’s
pretty bleak,
gentlemen. The
earth’s climate is
changing, the
mammals are
taking over, and we
all have brains the
size of a walnut.”
“Now this
end is called
the
thagomizer,
after the late
Thag
Simmons.”
“Evolution’s been good to you, Sid.”
Prebiotic Evolution
• The basic molecules of organic chemistry are
easily made
• The first self-replicating molecule was almost
certainly not DNA
• DNA assembles from simpler materials all the
time
DNA
• Deoxyribonucleic acid
• Total length of human DNA in a single cell is
about a meter
• A human body contains about 20 trillion
cells
• The total length of DNA in a human body is
thus 20 trillion meters, or twenty billion
kilometers, the circumference of the orbit
of Pluto.
Plants and Animals
• CO2 + H2O + Energy = Sugars, Starches, etc.
+ O2 (toxic waste). O2 is actually toxic
(even to us!)
• Idea: Take the sugars and starches (from
somebody else) combine it with the waste
O2, and get energy
Amazing Events in Life History
•
•
•
•
“Invention of Sex” - Who Needs It?
We are a team - Mitochondria
The Great Freeze 900-600 m.y. ago
Mass Extinctions
– Dinosaurs = 4th worst
– Permian extinction (220 m.y. ago) took out 90% of
all species
Randomness, Order and Evolution
• Are the following letter sequences random:
crvn, smrt, vrlo, gdje, trg?
• In Serbo-Croatian, the words mean,
respectively, red, death, very, where and town
square.
• Moral: the fact that something looks random
doesn't mean it is. It may convey meaning in a
way you don't understand.
Randomness, Order and Evolution
• Is the following number sequence random:
592653589793238462643383279?
• It not only looks random: it is random.
• But lacking in meaning? No. These are the
digits of pi beginning with the fourth decimal
place.
• Random does not mean “meaningless”
The Scientific Meaning of Random
• Something cannot be predicted with better
accuracy than that predicted by statistics.
• It takes as much information or effort to
describe an event fully as it does simply to
produce the event itself. The event is its
own simplest description
Randomness and Evolution
• Biological systems are far too complex to
describe or predict mathematically
• We have incomplete information,
• Significant events like climate change or
asteroid impact are unpredictable.
Randomness and History
• Mongols in Europe, 1242
– In three months, the Mongols wiped out military
opposition in the Balkans
– Ordered to turn back to select a new Khan
– Mongols never returned
• Gallipoli, February 1915
– Object: force passage to the Black Sea and Russia
– Intense artillery forced British fleet to retreat
– Turks had 5 minutes’ ammunition left
Can Order Arise Naturally?
• The Second Law of Thermodynamics is often
paraphrased as:
– ”Things always go from bad to worse”
– ”Disorder in the Universe is always increasing"
• The core of the Second Law is entropy
• Entropy can decrease locally if it increases
elsewhere
• Intuitive notions of disorder are of no
relevance whatsoever
Chemical Reactions are not Random
Na Cl Na Cl Na Cl Na Cl Na Cl Na
Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl
Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na
Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl
Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na
Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl
Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl
The Geologic Record
• Physical evidence records mostly smallscale, gradual processes
• Fossils show a gradual increase in
complexity with time
• Fossil forms intermediate between major
groups are well documented
• Over most of its history, life on Earth was
simple
Selection
• Deliberate selection for desirable traits by
humans (only since ca. 1700)
• Unsystematic selection for desirable traits
by humans (domesticated animals and
plants)
• Unconscious and unintentional selection by
humans (self-domestication of animals)
• Natural selection with no human
intervention at all
Lessons from Selection
• Artificial selection has produced organisms
radically different from their natural state
• Natural selection has resulted in dramatic
changes in natural populations with and
without human intervention
• Microorganisms and viruses change with
dazzling speed (mutation of flu viruses,
resistance to antibiotics)
This Descended from Wolves?
Prelude to Evolution
•
• 1750 •
•
• 1800 •
Biology
Linnaeus
Selective Breeding
Lamarck
• 1825
• Voyage of Beagle
• 1850 • Mendel - genes
• Origin of Species
Geology
Hutton
LyellUniformitarianism
Geologic Column
Linnaeus
• Classification of Organisms
• Kingdom-Phylum-Class-Order-FamilyGenus-Species
• Included Man and Apes in the Primates
• Encountered little opposition
• System was viewed as descriptive only
• Static, hierarchical, meshed with social
prejudices of the day
Classification of Dogs and Humans
•
•
•
•
•
•
•
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order Carnivora (Dogs) Primates (Humans)
Family Canidae
Hominidae
Genus Canis
Homo
Species familiaris
sapiens
The Five Kingdom System
•
•
•
•
•
•
Animals
Plants
Protista (one-celled organisms)
Fungi
Bacteria*
Ediacaran Fossils? (ca. 700 m.y. ago)
What’s Bigger Than a Kingdom?
• Bacteria differ from all other kingdoms in
lacking a cell nucleus
• We need a bigger box
• Superkingdoms or Domains
– Monera (Bacteria)
– Archaea
– Eukarya (have cell nucleus)
• Need electron microscopes and molecular
biology to see differences
Prelude to Evolution
•
• 1750 •
•
• 1800 •
Biology
Linnaeus
Selective Breeding
Lamarck
• 1825
• Voyage of Beagle
• 1850 • Mendel - genes
• Origin of Species
Geology
Hutton
LyellUniformitarianism
Geologic Column
Jean Lamarck, 1795
• Animals change in response to their
environment
• Changes passed to offspring
• Example: the Giraffe
• First modern theory of evolution
• Wrong, but contributed the idea that the
environment shapes organisms
Prelude to Evolution
•
• 1750 •
•
• 1800 •
Biology
Linnaeus
Selective Breeding
Lamarck
• 1825
• Voyage of Beagle
• 1850 • Mendel - genes
• Origin of Species
Geology
Hutton
LyellUniformitarianism
Geologic Column
Why was Darwin on the Beagle?
• British Navy SOP: ship’s surgeon (Dr.
McKenzie) is the expedition naturalist
• Rigid rules against fraternization
• Depression ran in Captain Fitzroy’s family
• Solution: hire an extra civilian naturalist
• Real job: social peer and gentleman
companion to the captain
• Problem: Darwin and Fitzroy were ideological
opposites
Evolution By Natural Selection
• Charles Darwin and Alfred Russell Wallace,
1859
• Organisms are adapted to their
environments
• Individuals vary
• More organisms are born than can possibly
survive
• Variations best suited to the environment
tend to survive and be passed on.
Why the Furor over Evolution?
• Pieces had been falling into place for over
100 years
• All the main tenets of Natural Selection
were well known
• Seemed Cruel
• Seemed purposeless (“random”)
• Conflicts with Religion
• Sexual Connotations
• Ideological Abuses
Sexual Connotations
• This was the Victorian era, and you can’t
discuss evolution without reproduction
• For an allegedly prudish era, they produced
a lot of undraped art and figureexaggerating fashions
• They weren’t so much prudish as mindnumbingly sentimental
How
Sentimental
Were the
Victorians?
Conflicts with Religion
• Death and the Fall
– Traditional: Death due to Adam’s fall
– Darwin: Death is intrinsic part of life
– So where does Christianity fit?
• Could a merciful God design Natural
Selection?
– The Paradox of Predestination
– Does predation have any moral dimension?
• How to Interpret the Bible?
– Literal versus metaphorical and allegorical
Ideological Abuses
• Evolution Disproves Christianity
– Atheism vs. Fundamentalism
• Evolution Negates Purpose in Life
– Nihilism vs. Religious and Marxist Schools
• Evolution = “Survival of the Fittest”
– Social Darwinism vs. Religious and Marxist
Schools
• Racist Applications
The “Package Deal” Mentality
• Proving part of a logical chain proves the
whole thing
• Extremists have a tendency to accept
opponent’s arguments at face value
• Example: The Shroud of Turin
– Purported burial shroud of Christ
– Radiocarbon dated to Middle Ages
Suppose the Shroud is Genuine?
• Is Cloth First Century?
• Is Image First Century?
• Is Image that of a dead body?
• Is Image That of Christ?
• Is Image Natural?
• Where is the body?
Bottom Line: Even if Shroud is that of
Christ, proves nothing doctrinal
“Evolution Disproves Christianity”
• Where did all these atheists come from?
• They were there all along, but keeping a low
profile (compare resurgence of racism in
recent years)
• Moral: suppression is always more dangerous
to the suppressor
• Two final words: Soviet Union
The Five Fundamentals (1910)
•
•
•
•
•
Literal Inerrancy of the Bible
Virgin Birth and Divinity of Christ
Atonement for sin at the Crucifixion
Resurrection of Christ
Second Coming
How Fundamentalists See It
The Scopes Trial, 1926
• Intended as a deliberate test of Tennessee’s
anti-evolution law
• Clarence Darrow (defense) vs. William
Jennings Bryan (prosecution)
• Climax came when Darrow grilled Bryan on
the stand
• Inherit the Wind, based on the trial, is good
drama but very inaccurate history
The Biggest Single Misconception
About Religion
• Many scientists consciously avoid saying
“science believes”
• Draw distinction between subjective beliefs
and documented evidence
• PROBLEM: EVERY RELIGION REGARDS ITS
DOCTRINES AS PROVEN FACTS
How Three Societies (Mis)applied
Evolution
United States
• Unbridled competition, “survival of fittest”
Soviet Union
• Marxism as continuation of evolution
Nazi Germany
• “Purification” of gene pool
Lysenko (USSR 1930’s)
• Rejected Darwin because of social darwinist
abuses of evolution, “purposelessness”
• Reverted to Lamarckian theories
• Likened struggle for existence to Marxist
class struggle
• Was close friend of Josef Stalin
• Effectively shut down Soviet biology 19301945
Racism and
Evolution
(Ernst
Haeckel,
1874)
One Final Question
• “Survival of the Fittest”
• What does “fittest” mean?