BIOS 3300 CH 2 LEC
Page 1: Introduction
Title: Natural Selection and the Nature of Science
Course: Bios 3300
Page 2: Genetic Changes in Cauliflower
Molecular biology reveals genetic alterations leading to cauliflower from wild cabbage.
Expression of various CAULIFLOWER gene alleles is observable when APETALA1 gene is absent.
A mutation from GAG to TAG results in the loss of function of APETALA1.
Farmers favored this mutation, causing plants to be homozygous for this loss-of-function allele.
Page 3: Postulates Leading to Evolution by Natural Selection
Postulate 1: Variation exists within populations.
Nearly all traits exhibit variation.
Example: Variability in human nipple counts.
Mutations occur at low frequencies.
Page 4: Passing Variation to Offspring
Postulate 2: Some variation is inherited from parents to offspring, primarily through genes.
Page 5: Survival and Reproduction Success
Postulate 3: Some individuals are more successful in surviving and reproducing than others in each generation.
Page 6: Questions on Survival
Rhetorical question: Why can't every baby bird survive and reproduce??
Page 7: Nature of Fear in Survival
Reference to Alfred Hitchcock's film "The Birds," highlighting fear associated with animal survival.
Page 8: Reproduction and Population Density
Example: Female German cockroach (Blatella germanica) produces 80 young every six months.
Implication: Exponential growth could lead to significant population density in households if all offspring survived.
Page 9: Additional Postulates of Natural Selection
Postulate 4: Survival and reproduction are not random but are associated with variation.
Page 10-11: Galapagos Islands and Finch Evolution
Overview of evolutionary studies on finches in the Galapagos Islands.
Page 12: Finch Species and Variation
Examples of various finch species:
Small ground finch (Geospiza fuliginosa)
Large insectivorous tree finch (Camarhynchus)
Various other finch species with different adaptations.
Page 13: Assessing Finch Population Variation
Graph indicating finch population sizes relative to beak depth.
Question: Is the finch population variable?
Number studied: N = 751.
Page 14: Heritability of Variation in Finch Beaks
Data showing offspring beak depth correlation (1978).
Midparent beak depth measured against offspring beak depth.
Page 15: Success in Finch Survival
Graph illustrating the number of finches surviving across years (1975-1978) with fluctuations.
Page 16: Seed Abundance and Adaptation
Drought impacts seed availability and characteristics (thicker shells).
Graph displaying seed abundance over time related to drought conditions (1975-1978).
Page 17: Seed Characteristics Over Time
Changes in average seed size and type influenced by ecological conditions.
Page 18: Non-Random Survival and Reproduction
Graph comparing beak depth before and after the drought, highlighting selective survival of certain traits.
Consider: How would randomness in survival alter this graph?
Page 19: Evidence of Evolution in Finch Populations
Comparison of finches hatched before and after drought highlighting evolutionary changes based on environmental pressures.
Page 20: Characteristics of Natural Selection
Individual as primary unit: Natural selection acts on individuals, but change is measured in populations.
Natural selection is phenotype-based, while evolution reflects shifts in allele frequencies.
It is a reactive process responding to past variations rather than predicting future traits.
New traits arise despite natural selection's action on existing variations.
Page 21: Co-opting Existing Traits
Example of panda's thumb as an adaptation of existing anatomical structures for new functions.
Page 22: Nature of Science
Illustrative content emphasizing scientific reflection through visual examples (NBC photo contest about nature).
Page 23: Definitions and Philosophy of Science
Exploration of terms associated with science, its history, and philosophical implications.
Page 24: Reasoning in Science
Inductive Reasoning: From specific observations to general conclusions.
Deductive Reasoning: Using general premises to reach specific implications.
Page 25: Scientific Method: Classical Model
Observation without preconceptions leading to universal truths.
Example of historic scientific challenges (e.g., Newton's theories).
Page 26: Discovery of Neptune
Urbain Le Verrier's hypothesis about Neptune's existence based on Uranus' orbital anomalies.
Confirmation through telescope observations, culminating in Voyager 2's mission.
Page 27: Increased Precision Model
Enhanced process involving deduction, testing, revising hypotheses.
Illustrative example of cell discovery and observational limitations.
Page 28: Cigarette Smoking and Cancer Evidence
Engaging audience interaction regarding the link between smoking and cancer.
Page 29: Historical Context of Smoking and Lung Cancer
Overview of smoking prevalence and its correlation with lung cancer's rise as the leading cancer type.
Page 30: Misinformation in Epidemiology
Tobacco industry tactics regarding the health implications of smoking.
Claims that low tar cigarettes are safe and misconceptions about tobacco types causing cancer.
Page 31: Correlation vs. Causation in Research
Highlighting the importance of differentiating between correlation and causation in scientific studies, especially regarding smoking and cancer.
Page 32: Naïve Falsification Model in Science
Overview of falsification principles and corroboration.
Null hypotheses play a critical role in reinforcing alternatives.
Page 33: Certainty and Scientific Knowledge
Understanding that absolute truths in science are nuanced and subject to doubt.
Page 34: Challenges in Naïve Falsification
Examples of instances where falsification fails, particularly in complex scientific theories like plate tectonics.
Page 35: Theory-Laden Data
Statement emphasizing that observed data is influenced by preconceived theories.
Page 36: The Nature of Scientific Explanation
Philosophical quote on the limitations of scientific experimentation and the quest for ultimate truth.
Page 37: Hypothetico-Deductive Model
Overview of the dual process within science involving creativity and empirical validation.
Page 38: Influence of Culture on Science
Discussion on how social values and cultural viewpoints can shape scientific inquiry and norms.
Page 39: Paradigms in Science
Definition and significance of paradigms in scientific exploration.
Emphasis on broadening scientific perspectives and methodologies.
Page 40: Navigating Scientific Uncertainty
Questions raised on the management of uncertainty in scientific fields.
Page 41: Basic Decision Theory
Framework for systematic decision-making applicable across various contexts.
Page 42: Decision-Making Example: Taking an Umbrella
Steps in assessing likelihoods and making informed decisions based on evidence.
Page 43: Decision-Making for Pesticide Use
Example illustrating the complexities of approving pesticide use concerning human safety.
Page 44-45: Evaluating the Use of Pesticides
Probable hypothesis regarding pesticide safety.
Assessed need for evidence before making definitive conclusions on human health impacts.
Page 46: Statistical Decisions in Science
The rationale behind statistical significance in hypothesis testing and research methodology.
Page 47: Review and Quiz
Reminder to review course content and take the quiz (Quiz #2) on Canvas.