psalm 119:99-100

©2000 Timothy G. Standish

Psalm 119:99-100

99 I have more understanding than all my teachers: for thy testimonies are my meditation.

100 I understand more than the ancients, because I keep thy precepts.


Timothy G. Standish, Ph. D.

Descent With Descent With ModificationModification

Darwin’s TheoryDarwin’s Theory


EvolutionEvolutionAt least three distinct meanings:Change over time - The fact of evolutionNatural selection - The theory of evolutionNo Creator/God - The belief all organisms

descended from a single common ancestor produced by “natural” events


The World Before DarwinThe World Before Darwin 427-347 BC Plato - Believed in two worlds:

– An ideal perfect world which was eternal, but not perceived.

– An illusory world in which imperfection appears because of our imperfect perception.

As the ideal world is perfect and eternal, there could be no evolution, variation from the perfect ideal is only perceived in organisms, not real

This belief was incorporated into the church’s theology - God created a perfect world in which everything was perfect and thus any variation was from the ideal God had made.


Before Darwin Cont.Before Darwin Cont. 384-322 BC Aristotle - Was ambivalent about Plato’s two-

worlds philosophy Recognized a scale of complexity in organisms Proposed a “scala naturae” (scale of nature) ranging from

simple to complex organisms Aristotle proposed a ladder of life with simple organisms

forming the lower rungs and complex organisms the top. Each organism was allotted its rung and could not be moved from it

This belief was also incorporated into the church’s theology


Before Darwin Cont.Before Darwin Cont. Linnaeus 1707-1778 - Swedish physician and botanist

– Sought to classify, or organize nature– The father of taxonomy or systematics– “Deus creavit, Linnaeus disposuit” (God creates, Linnaeus arranges)

Lamarck 1744-1829 - Published his theory of evolution in 1809– Proposed that organisms responded to “sentiments interieurs” (felt

needs) by evolving Mathus 1766-1834 - Proposed the utterly dismal theorum:

– All populations of organisms grow until resources are completely utilized so that each individual lives at the razor’s edge of existence


Before Darwin, Cont.Before Darwin, Cont. Cuvier 1769-1832 - Father of Paleontology, the study of fossils

– Believed fossils were a record of life over time– Interpreted the fossil record in the context of catastrophism where

strata in the rocks represent catastrophic events James Hutton - Scottish geologist who, in 1795, proposed the theory

of gradualism– Gradualism - Geological strata were laid down over a long period of time– Gradualism is a logical outgrowth of uniformitarianism, the belief that the

way things are now is the same as they were in the past. As mountains are eroding slowly now and basins are filling gradually, it follows that if the slow rate occurred in the past, laying down the amount of sedimentary rock we now see must have taken a long time.


Erasmus Darwin (1731-1802)Erasmus Darwin (1731-1802) Charles’ grandfather - Physician, radical and free-thinker Influential in publishing Linnaeus' works in English Believed existing life forms evolved gradually from earlier species Published Zoönomia (1794-1796) ascribed evolutionary development

to organism's conscious adaptation (close to Lamarck) Phytologia ("The study of plants") contains the earliest detailed

description of photosynthesis and the geological principles of the artesian well

Believed that cross-fertilization was a superior form of reproduction to self-fertilization


Charles Darwin (1809-1882)Charles Darwin (1809-1882) As a theology major at Cambridge

University, Darwin was taught a variation of the Greek view of reality

Was invited to travel around the world on the HMS Beagle surveying plant and animal life in the southern hemisphere

Compared the theory he had been taught with reality and could not reconcile the two

Proposed his theory of natural selection in The Origin of Species published in 1859


GalapagosIslands

Falkland Islands

The Voyage Of The BeagleThe Voyage Of The Beagle

The object of the expedition was to complete the survey of Patagonia and Tierra del Fuego . . . to survey the shores of Chile, Peru, and some islands in the Pacific-and to carry a chain of chronometrical measurements round the World.

Charles Darwin in The Voyage of The Beagle

SouthAmerica

Rio deJaneiro

England

Cape Verde Islands

AustraliaSydney

New Zealand

Mauritius

CocosIslandsTahiti


The Logic Of DarwinThe Logic Of Darwin The fossils in South America were different from the animals

that lived there now, but some seemed to be related in some way

If fossils were a record of the past (Cuvier) then there must have been change (evolution) between the past and now

Change is happening slowly thus to get change must have taken a long time (uniformitarianism)

The rock strata took a long time to form (Hutton - gradualism) thus lots of time is available for evolution

Organisms evolved over long periods of time


The Mechanism Of EvolutionThe Mechanism Of Evolution Darwin was not the first to propose evolution, Lamarck and others

had done it before him Darwin’s real contribution was a credible mechanism for

evolution - Natural Selection Natural selection is based on two points:1 The reproductive capacity of organisms exceeds the carrying

capacity of the environment2 Variation in organisms makes survival a non-random event -

Some variants are more likely to survive in a given environment Of the excess products of organisms’ reproductive capacity the

most fit survive - Survival of the fittest


Naturalism - The belief that all phenomena can be explained in a rational way, in terms of natural causes, without invoking the supernatural

Because Darwin proposed a natural cause (natural selection) for organisms’ origin his theory is considered scientific; religious accounts invoking the supernatural are not

The Triumph of NaturalismThe Triumph of Naturalism


UniformitarianismUniformitarianismUniformitarianism - The belief that nature

is the same (uniform) today as it has always been

Uniformitarianism is true absolutely all the time

With absolutely no exceptions . . .Except when it invalidates our theories.


Evidence For EvolutionEvidence For Evolution Biogeography - The geographical distribution of organisms reflects

their origin and isolation from other species Fossil Record - The fossil record contains missing links between

present species and their ancestors . . . sort of . . . maybe Comparative Anatomy - Homologous (similar) structures must have

evolved from the same ancestral structure . . . except when we don’t think two organisms shared a common ancestor with that structure.

Molecular Biology - More or less the same idea as comparative anatomy - Similar genetic information indicates common origin

Comparative Embryology - Similar organisms go through similar development


In His Own WordsIn His Own Words

"I may, of course, be egregiously wrong; but I cannot persuade myself that a theory which explains several large classes of facts can be wholly wrong...."

Charles Darwin, November 13, 1859, in letter to L. Jenyns

psalm 119:99-100

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