Principles and Unifying Themes
• Fossils = remains of past life
• Layered rocks have initial states and are deposited in chronological
order (Steno)
– Lateral continuity
– Original horizontality
– Superposition
Principles and Unifying Themes
• Principle of fossil correlation (Cuvier & Smith)
– Evolutionary clock
• Uniformitarianism (Lyell)
– actualism
• Gradualism
• Neocatastrophism
The Scientific Method
• How Science is done?
• What do we mean by the scientific method?
• Hypothesis => what is a hypothesis
– a falsifiable explanation for a set of observations
• Must have an alternative hypothesis
• A good hypothesis is a working hypothesis.
The Scientific Method
• Make predictions from the hypothesis, if valid then…….
• Testability=> must be able to test your hypothesis
– experimentation
– empirical observations
• Reproducibility
• Assumptions
The Scientific Method & Historical Geology
• Historical Sciences = cannot strictly apply the scientific method
• Results not reproducible
• Predictions are not possible: know the results - must interpret the
cause
• Falsifiability not always possible
The Scientific Method & Historical Geology
• Example:
– Ho: mammals displaced the dinosaurs because they were better adapted
– Ha: mammals only became successful after the dinosaurs went extinct
• Mesozoic mammals small and not diverse
• Only diversify and become large after dinosaur extinction