evolution of evolutionary thinking (17 th, 18 th, 19 th centuries)

Evolution of Evolutionary Thinking

(17th, 18th, 19th centuries)

“Pre-Scientific” Ideas(4th & 5th C. BCE)

• From Greece & Rome (i.e. Aristotle)

• Essentialism = “Essential” form of every natural entity, organisms we see today are inexact copies of the ideal

• Typological thinking = There are “ideal types” of each organism

• Ideas support biblical creation

Ideas from Medieval Europe

(c. 500-c.1500)• Great Chain of Being = All living forms

progress from imperfection to perfection, least to most complex

• Literal Interpretations of Bible are True: * Earth and all its diversity created by God* Earth’s history is short (c. 6000 years)* World is static* Change initiated by divine intervention

To Summarize:Western European World

View(Up until the 1600s)

The world is an unchanging domain of short duration that

will end by divine intervention when the forces unleashed by creation play themselves out.

Reverend John Ray (1628-1705)British Professor of Greek & Mathematics,

Botanist• All Living Things Fixed

in Present Form After 6th Day of Creation

• Books on Botany = Primary Source for Methods Used in Later Classification Systems

• Species = Indivisible Unit, All Individuals Who Share a Common Line of Descent

• Fossils = Organic Origin (not from thunderclaps)

Reverend John Ray (1628-1705)British Professor of Greek & Mathematics,

Botanist

Ray’s books:

• most complete taxonomic survey of nature to that date

• His categories were based on anatomical characteristics (v. essences)

Carolus Linnaeus (1707-1778)

Swedish Botanist • Wrote: The System of

Nature (1735)=initial standard for scientific names of species

• Naming: System of Binomial Nomenclature, i.e. Homo (genus) sapiens (species)

• Classification: based on anatomical attributes

• Fixity of Species = members of different species can not produce fertile offspring

Today’s Classification SystemExamples:

Human Chimpanzee

Kingdom Animalia Animalia

Phylum Chordata Chordata

Class Mammalia Mammalia

Order Primates Primates

Family Hominidae Pongidae

Genus Homo Pan

Species Sapiens Troglodytes

HOW DID WE GET HERE?INTERPRETING THE WORLD AROUND US

1. Catastrophism

Series of disastrous events explain today’s geology (often following Bible)

2. Uniformitarianism Geological processes of the past were the

same as those seen today

• James Hutton (1726-1797) Scottish Geologist

• Geologic Time Spanned Great Antiquity (way more than 6000 yrs.!)

Geologic Time Today• First 50 min: single-

celled organisms (3.8 bya)

• Last 10 min: Animals arrive (543 mya)

• 1/100 second: First Hominids evolve (5-6 mya)

• Moral = Humans came late to the party of life on Earth!

Earth = 4.5 billion ya

3. Stratigraphytechnique of identifying and tracing

geologic strata by their fossil contents

Superposition: Fossils in any given stratum are older than those above them and younger than those below them

Comte Georges-Louis Leclerc de Buffon (1707-1788)

French Naturalist• Wrote Natural History =

1st major scientific synthesis of European Biology, 44 volumes!

• Uniformitarian = Argued that tides and currents slowly shaped Earth (not a catastrophist)

• Argued that living things existed 40,000 Years Ago!

• Theological Faculty in Paris forced de Buffon to reject his ideas that contradicted Moses

Jean Baptiste Pierre de Monet Lamarck (1744-1829)

French Naturalist (Buffon’s Student)

• Evolutionist• Books: Philosophie

Zoologique (1809) & Natural History of the Invertebrates (1815)

• Theory of Acquired Characteristics, mechanism for evolution

• Lived near poverty last 20 yrs. of life

Lamarck’s Theory of Acquired Characteristics

• A body can produce new organs when a new want or need is present

• Organs develop in proportion to their use

• Changes that occur in the organs of an individual are passed on to its offspring

Georges Leopold Cuvier (1769-1832) French Naturalist (Lamarck’s Student)

• Brilliant Anatomist

• Law of correlation = form of an organ depends on its purpose

• Identified over 150 Fossil Species! (many no longer living)

• Series of Creations, Series of Catastrophes = Extinction of Many Species

• Disagreed with Lamarck that Humans Evolved from Higher Apes

• Most Famous French Scientist of His Time

Cuvier’s Reaction Against Lamarck• C and L = radically different conceptions of

human history

• C = idea that humans evolved from Apes was a personal offense, so purposefully destroyed L’s academic standing

• Losing his sight, L was being led to his lectures by one of his children

• Last 20 years of life, L lived near poverty, but dictated 11 vols. of his Natural History to daughter, from memory

• French Science belonged to Cuvier through Napoleon’s reign & fall

Charles Lyell (1797-1875)Scottish Geologist

• Wrote: Principles of Geology (1830) = geologic time in terms of Millions of Years (mya), upsetting geologic ideology of the day!

• Uniformitarian = (anti-catastrophist) Argued that long geologic time needed for slow processes of erosion (water, waves, wind)

• Ideas gave Evolutionists the gift of time

• Great Britain’s leading geologist, knighted in 1848

ConclusionsEvolutionary Thinking was REVOLUTIONARY

(Rocking the Foundations)

• Questioned the Bible, the Word of God

• Humans were part of the Natural World (could we share a common ancestor with apes?)

• Questioned idea that the world is “orderly”

• Taught People HOW to ask questions through SCIENCE, instead of Theology

• Questioned the ruling elite as rulers ordained by God