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Natural Selection, Evolution, and Evolutionary Ecology

This resource delves into the Levels of Ecological Explanation by Dr. James Danoff-Burg, covering Ultimate and Proximate factors, Human influences, Abiotic changes, and Biotic interactions. It delves into Evolutionary influences and the Progress of Ecological Inquiry, emphasizing the importance of pitching questions at the right level and distinguishing between ultimate and proximate answers. The branches of EvolEcol - Intraspecific and Interspecific - are explored, highlighting the role of Evolution in shaping diversity through time and within lineages. The concepts of Natural Selection, Intraspecific Variation, and the impact of resource gradients on diversity are examined, guiding readers on planning and conducting related activities in evolutionary ecology research.

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Natural Selection, Evolution, and Evolutionary Ecology

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  1. Natural Selection, Evolution, and Evolutionary Ecology Dr. James Danoff-Burg Columbia University

  2. Levels of Ecological Explanation • Ultimate • Evolutionary influences • Proximate • Human influences • Abiotic changes • Biotic interactions Most ecologists explore the last three levels

  3. Progress of Ecological Inquiry? • Explore plausible ultimate answers • If one is supported, stop • If no ultimate answers are supported, explore proximate answers

  4. Rationale • Need to pitch the question at the right level • Example • Why are Penguins only in the Southern Hemisphere? • Proximate - insufficient food, too many predators, lack of shelter, etc. • Ultimate - historical and thus evolutionary distribution --> favored at present

  5. Two EvolEcol Branches • Intraspecific • Relative selective value of different traits • Origin of intraspecific diversity • Interspecific • Behavioral ecology (comparative studies) • Systematics and phylogeny Common feature of all branches - Evolution!

  6. Evolution • Change through time within a lineage • Mechanisms / Producers of Variation • Genetic drift • Phenotypic plasticity • Natural Selection Natural Selection  Evolution

  7. Natural Selection • Proposed by Darwin and Wallace • Evolutionary mechanism • One way that variation exists and is maintained in a population • Value is relative to local competitors • Only a negative action • Only selection AGAINST a form of a trait • Never selection for a trait

  8. Intraspecific Variation • Possible sources: • Genetic drift • Phenotypic plasticity • Natural Selection • How to differentiate between them? • Genetic fixation / continuity through lineages • Use traits that do not change in response to changes in environment

  9. Today’s Activity • How do changes in a resource gradient affect intraspecific diversity? • Are these changes due to natural selection? • Choose an organism with the following characteristics: • Low vagility • Does not disperse aerially • Clearly marked adult stage • Traits under study do not change

  10. Activity Tasks • Plan activity • Collect data and enter into eBiome • Analyze our data • Wait for data from other sites • Jointly analyze all data • Make conclusions about relationship • Posit future studies to distinguish between evolutionary mechanisms

  11. Planning - To be Determined: • Environmental variable • Experimental organism • Organismal trait for study • Statistical technique to use, justify

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