Anthropology Analysis Assignment
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Ch2pp.pptxChapter 2 Origins of Evolutionary Thought
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What is Science?
Science is a process, not a result!
Science is the process through which the
natural world is explored and understood.
Video: The Nature of Science
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The Scientific Method
1. Observation
4. Experiment/test
2. Deduction
3. Hypothesis
5. Conclusion
6. Repeat
7. THEORY
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More about “Science”
Hypotheses must be testable! If a hypothesis (proposed explanation for observed phenomena) is not testable, then the hypothesis is not scientific.
Science is the process that we use to investigate, to question and to verify or disprove a hypothesis.
Science is self-correcting.
If a hypothesis can be falsified (proven wrong through application of the scientific method), then we have to rethink the proposed explanation for the observed phenomenon.
Early Scientific Thinkers
A word about ancient Chinese science, Egyptian science, Mayan science, Arab science … They were first!
Ancient Greeks
often are credited with the first written efforts to understand the natural world and our place in it
Aristotle (born 2400 years ago) talked about:
Chain of Being
Fixity of Species
Geocentric Universe
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The Roots of Modern Science
The Renaissance (14th – 16th centuries)
Copernicus (1473-1542): Heliocentric Universe
(what is this?)
Galileo (1543-1642): supported Heliocentrism
Backlash against scientific observations:
Archbishop James Ussher (1581-1656)
Calculated the Day of Creation based on Biblical genealogies.
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Linnaeus and Systema Naturalae (1735)
taxonomy
binomial
nomenclature
What is a taxon (plural = taxa)?
A unit or category for classification
What is binomial nomenclature?
A two-name classification system for identifying species
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The Road to the Darwinian Revolution
Georges Cuvier (1769 - 1832) = Catastrophism
Jean-Baptiste Lamarck (1744 - 1829)
Inheritance of acquired characteristics (what is this?)
James Hutton (1726 - 1797)
and Charles Lyell (1797 - 1875)
Uniformitarianism (what is this?)
Thomas Malthus (1766 – 1834)
Population Economics: War, disease, famine are necessary to prevent overpopulation
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Lamarck’s contributions
Lamarck popularized two important ideas about species change over time. The first one was correct. The second one was not.
Steady and predictable “improvement” of species over time, such that species would be successful in their given environments.
Creatures could improve their bodies through experience and/or need and then pass on these acquired characteristics to their offspring. This idea of “Inheritance of Acquired Characteristics” was popular in the early to mid-1800’s because it explained that a creature would somehow “grow” traits that were needed and lose what was not. This is not how Evolution works.
Hutton/Lyell’s Uniformitarianism:
James Hutton Charles Lyell 1726 - 1797 1797 - 1875
Observable natural processes shape physical landforms and features over very, very long periods of time.
The same gradual geological processes we observe today were operating in the past.
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Malthus’ Population Economics
Populations of laborers grows faster than available food resources:
Human reproduction is exponential (2 x 2 x 2 x 2)
Resource growth is arithmetic (2 + 2 + 2 + 2)
“Natural” forces work to keep reproduction at manageable levels.
War
Poverty
Infectious disease
Charles Darwin (1809 – 1882)
Voyage on the HMS Beagle (1831-1836)
Naturalist
Social elite
Well-educated
Knew about Lamarck, Hutton/Lyell, Malthus
Synthesized previous information to form ideas on Origin of Species in 1859
Who was Charles Darwin?
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Darwin’s Observations
The Galapagos Islands
Variations of tortoise shells on different islands
Finch variation correlates with environment
Adaptive radiation from ancestor on mainland
Natural Selection as the mechanism for Evolution
As a “Gentleman Farmer” in England
Artificial Selection (selective breeding) is analogous to Natural Selection
Another voice
Alfred Russel Wallace (1823 – 1913).
Independently came up with the idea of Natural Selection in 1857.
Not “social elite”
Father of Biogeography
Read “Insights and Advances” section in the textbook for this story.
Differences between Darwin and Wallace
Darwin argued that competition, survival and reproduction between individuals are primary factors in evolution.
Wallace emphasized environmental pressure on groups (populations) to force adaptations through natural selection.
Darwin was influenced by Wallace’s ideas about Natural Selection and incorporated them into his own thesis on Origins of Species.
Refining the Theory of Evolution by Natural Selection
Observation 1: All organisms have the potential for explosive population growth, yet populations are roughly stable…
Deduction 1: There must be a struggle for existence (competition).
Observation 2: Nature is full of variation
Deduction 2: Some variations are favored (adaptive) while others are not.
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Modern Synthesis on Natural Selection
1) Organisms have the potential for reproductive rates that outstrip the rate of increase of food supplies.
2) Biological (genetic) variation exists within all species.
3) There is constant competition among individuals for survival.
4) Individuals with favorable traits are more likely to survive and reproduce.
Modern Synthesis on Natural Selection
5) Environment (nature) selects traits that are favorable.
Favorable traits are passed on to offspring at a higher rate than non-favorable traits, which changes the gene frequency in a population over time.
Video: What is Evolution?
http://www.statedclearly.com/what-is-evolution /
What is “fitness”? Reproductive success
What is an “adaptation”? Trait that helps the creature survive and reproduce
What is a “mutation”? Genetic change that results in a potentially adaptive trait
Natural Selection and Adaptation
Adaptations are the physical result of genetic mutations in individuals.
Reproductive success of individuals (“fitness”) is based on physical adaptations. Those successful individuals are “selected” by nature (Natural Selection).
The unit of natural selection is the individual The unit of microevolution is the population
Individuals do not “evolve” … Populations evolve! Evolution is the change in traits from generation to generation, which requires reproduction (usually two individuals mating).
Evolution that can be seen or tracked from one generation to the next is called “Microevolution”.
For Natural Selection to work …
The trait is question must show variation between individuals.
The trait in question must be heritable.
The environment must exert some pressure on the trait.
Video: What is Natural Selection?
http://www.statedclearly.com/natural-selection /
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Science and Creationism
Faith vs. Testable Evidence
Is “Creationism” a Science?
What is
“Intelligent Design”
What does “science” require that “faith” does not?
Can “science” answer all questions about life?
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Darwin’s Rib Article
What is the controversy?
How was this investigated?
What was the outcome?
Why is this discussion important?
Check your syllabus! The Short Essay Assignment for this class is due on Friday, no later than 11:00 p.m.
Study Guide
1. Discuss the process of science, including observation, hypothesis formulation, and experiment (testing).
2. Explain how the scientific method is self-correcting.
3. Explain the roots of modern science and the concept of evolution:
Contrast catastrophism versus uniformitarianism.
Discuss the conflicting viewpoints of Bishop Ussher, Georges Cuvier, James Hutton and Charles Lyell.
Who was Thomas Malthus and why is he important to the study of evolution?
4. Compare and contrast Jean Baptiste de Lamarck's view of evolution and heredity with those of Charles Darwin.
5. Identify the contributions of Charles Darwin and Alfred Wallace to evolutionary theory.
6. Describe the process and provide examples of natural selection including those from the Galápagos Islands.
7. How is the process of Science different from ideas of Creationism?
Why is Intelligent Design not considered to be a scientific approach?
