Transcript Chapter 1 The Nature of Science and Evolution, and

Chapter 1
The Nature of Science
and Evolution, and
Evolution as Science
Every Primitive Person Was a Biologist
For at least 2 million years of human prehistory
Agriculture Arose 13,000
to 15,000 Years Ago
From foraging to farming and in the late
20th century to factory food feeding
Impact of Agriculture
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Relatively permanent villages
Reduced contact with wildlife
Division of labor in the community
Shift to a hierarchical culture:
headmen, chiefs, kings
• Fewer individuals are experienced with
or understand the natural world
Most Cultures Have Creation Myths
Atun, the Sun God (Egypt)
Pan Gu (China)
Unkulunkulu (Zulu)
Eden (Judeo-Christian)
Link for more
Creation Myths
Plumed Serpent God (Maya)
Judeo-Christian & Islamic
Theory of Special Creation
• All living “kinds” were created in a series of
separate special supernatural creations during
the six days of creation described in the Book of
Genesis.
• This creation preceded recorded history by only
a few centuries at most.
Explanation based on authority or revelation
Two Pairs of Related
Ancient World Views
Fixity of Species versus Evolution
And
A Young versus an Old Age for the Earth
Greek Natural Philosophers
Aristotle (384 – 322 B.C.E.)
Founders of Biological Thought
• Anaximander (610-547 B.C.E.) imagined a
transition from fish to reptiles to mammals
and birds
• Empedocles (490-430 B.C.E.) imagined a
type of spontaneous generation from an
assemblage of parts; only certain
successful combinations survived
• Heraclitus (5th century B.C.E.) imagined
change as the fundamental principal of the
universe
Aristotle (384 – 322 B.C.E.)
• Aristotle carried out dissections of animals but
not humans
• Aristotle made collections of natural objects and
creatures from the land and seas
• He recognized different kinds of organisms and,
for example, appreciated that sea mammals
were distinct from fish as were sharks and rays
• He studied fertilized chicken eggs and noted
the sequence of organ development over time
Aristotle
• Aristotle imagined the world could be
understood by the combination of observation
and reason
• Aristotle’s own observations were quite good,
but he was also naïve about accepting fabulous
tales about nature from others
• Aristotle wrote many books about many topics,
most of which are now lost
• Aristotle began as a gifted amateur but his
legacy was as an unquestioned authority,
holding back scientific progress for centuries
Some Mysteries Addressed
by the Natural Philosophers
• Cosmogenesis
– Where did the universe come from?
• Biogenesis
– Where did life come from?
• Evolution
– How do you explain the diversity of life?
• Humanity
– What does it mean to be human?
Theory of Special Creation
• James Usher/Ussher (1581 –
1656), Bishop of Armagh in
Ireland, was one of the leading
biblical scholars of the early
seventeenth century.
• Usher/Ussher is best known
today for his detailed and
influential chronology of the
world, which he argued began in
4004 B.C.E. (on Sunday the 23rd
of October to be precise!).
Ibn al-Haytham (“Alhacen”) (965 -~1040)
• Alhacen, a father figure for
Islamic science, made
significant contributions optics,
physics, anatomy, astronomy,
engineering, mathematics,
medicine, ophthalmology,
philosophy, psychology, visual
perception, and to science in
general with his early
application of the scientific
method
St. Thomas Aquinas (1225-1274)
• Scholasticism was the dominant
form of theology and philosophy in
the Latin West in the Middle Ages,
particularly in the 12th, 13th, and
14th centuries.
• It was both a method and a system
which aimed to reconcile the
Christian theology of the Church
Fathers with the Greek philosophy
of Aristotle and his commentators.
• Aquinas was the foremost classical
proponent of natural theology.
The Renaissance and the Great
Voyages of Discovery
Christopher Columbus
(1451-1506)
The Renaissance and the Great
Voyages of Discovery
Ferdinand Magellan
(1480-1521)
Sir Francis Bacon (1561 – 1626)
• The modern scientific method
crystallized in the 17th and 18th
centuries.
• Francis Bacon outlined a new
system of logic to improve on the
old philosophical process of
syllogism [deductive reasoning] in
his work Novum Organum (1620) —
a reference to Aristotle's Organon.
• The philosopher should instead
proceed through inductive
reasoning from fact to axiom to
physical law.
René Descartes (1596-1650)
• In 1637, René Descartes
established the framework for the
scientific method's guiding principles
in his treatise, Discourse on Method.
• A rationalist and mathematician,
Descartes is remembered for
“Cogito ergo sum” – [ “I think,
therefore I am.” ]
• Descartes studied animal physiology
through vivisection, believing
animals could not feel pain.
The Scientific Method
1. Produce a hypothesis.
2. Design and perform controlled experiments or
make observations that allow data relevant to
the hypothesis to be collected.
3. Analyze the data in an objective way against
the background of existing knowledge.
4. Draw conclusions that support or refute the
hypothesis.
Hypotheses for the Orbits of the
Planets of our Solar System
• Claudius Ptolemy
proposed a
geocentric
universe ~150 A.D.
• Nicolaus
Copernicus (14731543) shifted the
paradigm to a
heliocentric
universe in the
early 1500s.
The Age of Reason
• The Age of Reason or The Enlightenment
arose as the 17th century closed.
• The Enlightenment gave birth to critical
ideas, such as the centrality of freedom,
democracy, and reason as primary values
for society.
The Emergence of Science From the
Renaissance to the Age of Enlightenment
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Observation of the Natural World
Collection of Data
Hypothesis Formation
Hypothesis Testing
–experiment – experimental sciences
–data comparison – historical
sciences
• Formation of Laws and Theories
The Enlightenment and More Great
Voyages of Discovery
Captain James Cook
(1728-1779)
The Age of Reason
• The Enlightenment’s emphasis on rational
thought and behavior led to the market
mechanism and capitalism, the scientific
method, religious tolerance, and the
organization of states into self-governing
republics through democratic means.
• This world view nurtured the birth of
modern western science, in its descriptive,
experimental and historical modes.
Science and Events in the Past
• Careful observations and
comparative studies are important
tools in disciplines with historical
elements, e.g.:
• Astronomy
• Geology
• Paleontology
• Evolution
– (human history)
Evolution as a Science
• Evolution has been criticized as unscientific
because past events cannot be tested in the
laboratory.
• Evolution that occurred in the past can be
observed, documented, studied and tested,
e.g.:
– the sequence of the fossil record
– the adaptation of organisms to their environments
– the geographic distribution of organisms
– the comparison of DNA sequences
Evolution as “Only” a Theory
• Evolution by means of Natural Selection
(Darwinism) is among the foundational
theories in science — along with the
atomic theory, the theory of relativity, the
universal theory of gravitation.
• A theory does not become a “fact.”
• A scientific theory organizes and explains
collections of observations and facts!
Evolution: an Overview of the Term
and the Concept
• The word evolution had different meanings
in the past compared to the way we use
the word today
– Evolution as the development of an individual
– Evolution as the transformation of populations
between generations
– Transformation of populations (species) and
descent with modification: 1859 – the present
Evolution as the Development
of an Individual
• Original 17th century definition
– From the Latin evolutio,
unrolling
• 18th century theory of
preformation or encapsulation
(emboitement)
Figure 03A: Adult humans as preformed
within sperm, or within egg of the female
Evolution as the Transformation of
Populations between Generations
• In the 19th century, evolution came
to mean transformation of a species
or the transformation of the features
of organisms
Evolutionary Predecessors
• In the years before Darwin, many
biologists attempted to solve the mystery
of the “species question.”
Carl von Linné = Carolus Linnaeus
(1707—1778)
• This Swedish biologist
established the system
still used today for
naming organisms”:
binomial nomenclature
(genus + species).
• He was also a Biblical
creationist who initially
abided by and promoted
the view that species do
not change.
“God created, Linnaeus organized”
Historical Footnote
• Although Linnaeus has been credited
with inventing the use of binomials for
species names, the idea did not
originate with him.
• It originated with Gaspard Bauhin, a
Swiss botanist, and was first used in
1623, in his Pinax Theatri Botanici.
• However, the idea of the binomial
species name did not catch on then.
• Linnaeus actually reintroduced the use
of binomials for species names and
popularized it among naturalists.
Solanum tuberosum G Bauhin (1591) 
Carolus Linnaeus
“The WORLD is the Almighty’s theater . . . each object ought to be clearly grasped
and clearly named, for if one neglects this, the great amount of things will necessary
overwhelm us and, lacking a common language, all exchange of knowledge will be
in vain.” (1753)
Georges Louis Leclerc, comte
de Buffon (1707-1788)
• Buffon is best remembered for his
great work Histoire naturelle,
générale et particulière (1749–1778:
in 36 volumes, 8 additional volumes
published after his death by
Lacépède). It included everything
known about the natural world up
until that date.
• Buffon noted that despite similar
environments, different regions have
distinct plants and animals, a concept
later known as Buffon's Law, widely
considered the first principle of
Biogeography.
Georges Louis Leclerc, comte
de Buffon (1707-1788)
• Buffon drew the radical
conclusion that species must
have both "improved" and
"degenerated" (evolved) after
dispersing away from a center
of creation.
• He also asserted that climate
change must have facilitated the
worldwide spread of species
from their center of origin.
• Darwin later said that "the first
author who in modern times has
treated [evolution] in a scientific
spirit was Buffon."
Jean-Baptiste de Lamarck
(1744 - 1829)
• (a) J-B. de Lamarck worked most of his life at
the Muséum d’Histoire Naturelle in Paris. (b).
His academic position gave him a chance to
promote the idea that species change.
Lamarck’s World View
– Lamarck believed that all living things
are endowed with a vital force that
controls their development and
functioning and enables them to
overcome handicaps in the
environment: Vitalism.
– Vitalism, in one form or another, goes
back to the ancient Greek naturaI
philosophers and continued to have
advocates into the 19th and early 20th
centuries.
Scala Naturae
• Lamarck and essentially all European
naturalists before him accepted the idea of a
scale or ladder of nature, scala naturae, which
derives from Aristotle
• Characters and species were viewed on a scale
from primitive or lower to advanced or higher on
the ladder of life
• This progressive view of evolution remains in
the mind of the general public but has been
abandoned by science
Lamarck’s World View
In 1809, Lamarck published his four main principles:
1. The first organisms arose by abiogenesis.
2. Organisms have an innate power to progress toward
more complex and perfect forms (later termed
orthogenesis).
3. Organisms have an inner disposition to adapt their
characteristics in response to changes in the
environment (an aspect of vitalism for Lamarck but
similar to the modern term developmental adaptation).
4. Characters acquired in response to changes in the
environment were passed on to offspring (the
inheritance of acquired traits).
Lamarckism: The Inheritance
of Acquired Characteristics
• A regular and sustained program of weightlifting yields enlarged muscles, an
immediate physiological response of muscles to the increased effort
• However, these big muscles (somatic trait) remain with the individual that
endured the regular exercises, and are not passed to their offspring
• This is because the enlarged characteristics result from individual effort, not
from an inheritable genetic change (genetic trait)
Giraffe Necks
• Applied to giraffes,
Lamarck’s view (top)
would expect that
stretching giraffes
lengthened their necks to
reach tree-top vegetation,
and this acquired
characteristics was
passed to offspring
• In Darwin’s view (bottom),
giraffes with long necks
out competed those with
short necks who died for
lack of vital resources
Adaptation to Life in the Dark
Figure 02A: Surface-dwelling and cave fish
Figure 02C: Mexican axolotl
How could an organism behave differently
to acquire the loss of a pigment, even if
not synthesizing it reduces energy costs?
Figure 02B: Blind and non-pigmented
(albino) cave-dwelling axolotl
William Paley (1743-1805)
Paley’s Natural Theology; or, Evidences of the Existence and Attributes of the Deity
(1802) was a major influence on the young Charles Darwin
“Intelligent Design”
Is Nothing New
(1986)
Contemporary Evolutionary Biology
Responds to Intelligent Design
•
Richard Dawkins
(1941- )
“All appearances to the contrary, the only watchmaker in nature
is the blind forces of physics, albeit deployed in a very special
way. A true watchmaker has foresight: he designs his cogs and
springs, and plans their interconnections, with a future purpose
in his mind's eye. Natural selection, the blind, unconscious
automatic process which Darwin discovered, and which we now
know is the explanation for the existence and apparently
purposeful form of all life, has no purpose in mind. It has no
mind and no mind's eye. It does not plan for the future. It has no
vision, no foresight, no sight at all. If it can be said to play the
role of watchmaker in nature, it is the blind watchmaker.”
“The Bishop goes on to the human eye, asking rhetorically, and with the implication that
there is no answer, 'How could an organ so complex evolve?' This is not an argument, it
is simply an affirmation of incredulity.” ― Richard Dawkins, The Blind Watchmaker
(1986)
The End of Vitalism - 1828
• Friedrich Wöhler synthesizes urea by the
reaction of potassium cyanate with
ammonium sulfate
• Although Wöhler was attempting to
prepare ammonium cyanate, not urea
• Thus, Wöhler inadvertently discredited
Vitalism, the theory that the chemicals of
living organisms are fundamentally
different from inanimate matter, thereby
starting the discipline of organic chemistry
Evolution as the Transformation of
Populations between Generations
• Robert Edmond Grant (17931874)
• One of Darwin’s professors
and mentors
• Described the evolution of
invertebrate groups in 1826,
one of the first published
uses of “evolution” for the
transformation of organisms
Transformation and Descent with
Modification: 1859–Now
• From the publication of On the Origin of Species
in 1859 until 1900, evolution was studied as:
– the origination and transformation of species (one
species of horse → another species of horse)
– the transformation of major groups/lineages of
organisms and the search for ancestors
(invertebrates → vertebrates; fish → amphibians
– the transformation of features such as jaws, limbs,
kidneys, nervous systems within lineages of
organisms
Transformation and Descent
with Modification: 1859–Now
Figure 04: Progressive divergence within individual species
Darwin’s own diagram, from The Origin of Species,
illustrating a hypothetical phylogeny
Individuals, Populations and Evolution
• Organisms exist as individuals
• Natural selection acts on individuals but
individuals do not evolve
• Individuals exist in populations that
inhabit discrete ecological niches
• Sexually reproducing individuals exhibit
variation
• Limited resources leads to differential
survival
Individuals, Populations and Evolution
• Populations do not reproduce, individuals
reproduce
• Variation is an essential prerequisite for
natural selection
• Genetic composition of a population will
change due to drift (random forces) and
natural selection
• Populations may subdivide
• Populations or subsets of populations may
“crash” or become extinct
Figure T01: Comparison of Characteristics
of Individuals and Populations
We’ll talk about these Life Characteristics in later chapters.
Individuals Exist in Populations that
Inhabit Discrete Ecological Niches
• It is primarily the action of natural selection
which allows species to be successful in
their specific ecological niches
• We’ll look at the connections between
ecology and evolution throughout this
course
Different Lichen Species
Occupy Slightly Different Niches
© Popovici loan/ShutterStock, Inc.
Figure B01: Lichens
Chapter 1
End