Fossils and Earth History
Early Contributors
 A little history
 Remember the four questions……
 Greeks
 Interpreted large bones as belonging to a race of giants
 Asked questions about seashells in the mountain rock – had the
ocean once covered the land?
 Figured that the fossils were much younger than the rocks.
Perhaps the animals crawled in and were covered
 Leonardo da Vinci
 About 1500AD recognized that fossil shells were from ancient
marine life
 Argued that clams couldn’t travel miles inland and were too
fragile to be washed that far by a flood.
 Recognized communities similar to those living along the coast.
 Nicholas Steno
 Fossils formed along with the rocks
 Strata must contain a chronology of earth history
 In 1669 published his three principles: Superposition, Original
Horizontality and Lateral Continuity
 William Smith and Georges Cuvier
 Major scientific breakthrough
 1796 Smith proved the utility of fossils in the production of the
first geologic map before 1800
 Cuvier published in 1811 using fossils to divide the rock strata of
the Paris basin.
 Principle of Fossil Correlation: assemblages of fossils are
of a like age therefore strata containing them is also of a
l i k e age.
 Cuvier was a noted anatomist. He studied comparative
anatomy of living and fossil creatures.
 Cuvier explained the changes in fossil assemblages as the
result of catastrophic events.
 This view became known as catastrophism
 Organic evolution which stated younger organisms
descended from older ones was present 100 years
before Cuvier
 Buffon – 1749 published 34 volume work Historie Naturelle
 Established two fundamental concepts of evolution:
adaptation and inheritance
Charles Lyell - Published Principles of Geology in 1830 and
revised it for the next 45 years
 Uniformitarianism
 His work had a great effect on Darwin
 Erasmus and Charles Darwin – both had an impact on the
i dea of ev ol ut i on.
 Erasmus studied the breeding of cattle and determined
that characteristics of the parents were passed on to the
offspring.
 Charles, his grandson, became the “father of modern
evolutionary theory” with “Origin of the Species”
 Carl Linnaeus – mid 1700’s – developed the binomial
naming scheme for all living organisms that is still used
today.
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Kingdom
Phylum
Class
Order
Family
Genus
Species
Systematics
 Classifying organisms is known as taxonomy
 We will use Linnean classifications in this class.
 This is “classical” taxonomy. It is heirarchical….each level
grouped into higher levels
 Rules for naming organisms:
 Binomial nomenclature – Genus species, based on Latin
 Principle of priority – first name proposed in print is the valid
name. Once used, even as an invalid synonym they may never
be used again
 Principle of first reviser – when its not clear who published first,
the first person to revise the name decides the priority
 Principle of coordination – the first genus recognized in a family
names the family
 Principle of coordination – the first genus recognized in a family
names the family
 Homonymy – Names already used cannot be used again
 Type specimens – Specimen for which the new species/genus
etc is named. Presumably the best specimen available. Usually
kept at a museum or university to be available for study.
 Briefly about cladistics
 Based on shared derived characteristics
 Shows which organisms are more closely related based on
structure (4 legs)
 The relative incompleteness of the fossil record makes this
method problematic
Evolution
 Evolution is a fact, not a theory.
 Evolution is the change in genetic characteristics over
time. These changes are passed from one generation to
another.
 Changes to an individual after its birth (acquired
characteristics) will not be passed on.
 Characteristics that prove beneficial – a longer neck to eat
leaves higher on the tree – may become dominant
because those individuals are better fit to survive in their
environment.
 Evolution takes place over a long period of time – many
generations.
 New characteristics live “side-by-side” with old ones until
the old ones gradually die out
 Structure of the earth:
Fossils and plate tectonics