The Nature of Scienceand Evolution, and

Evolution as Science

Chapter 1

Every Primitive Person Was a BiologistEvery Primitive Person Was a Biologist

For at least 2 million years of human prehistoryFor 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

• 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)

Plumed Serpent God (Maya)

Unkulunkulu (Zulu)Pan Gu (China)

Eden (Judeo-Christian)

Link for moreCreation Myths

Judeo-Christian & IslamicTheory 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 RelatedAncient 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 Addressedby 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 (1473-1543) 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 theRenaissance to the Age of Enlightenment

• 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 ViewIn 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 Inheritanceof 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 02C: Mexican axolotl

Figure 02A: Surface-dwelling and cave fish

Figure 02B: Blind and non-pigmented (albino) cave-dwelling axolotlHow could an organism behave differently

to acquire the loss of a pigment, even if not synthesizing it reduces energy costs?

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 ureaurea by the reaction of potassium cyanate with ammonium sulfate

• Although Wöhler was attempting to prepare ammonium cyanate, not urea

• Thus, Wöhler inadvertently discredited VitalismVitalism, 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 (1793-1874)

• 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

Figure 04: Progressive divergence within individual species

Transformation and Descent with Modification: 1859–Now

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

• 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

Individuals, Populations and Evolution

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

Figure B01: Lichens © Popovici loan/ShutterStock, Inc.

Different Lichen Species Occupy Slightly Different Niches

Chapter 1

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