Principles of Ecology LSU BIOL 4253 Sections 1

Principles of Ecology (LSU BIOL 4253, Sections 1 & 2, Spring 2018) Composite satellite image (“Blue Marble 2012”) from Wikimedia Commons

Dr. Kyle E. Harms A 312 Life Sciences Annex kharms@lsu. edu https: //sites 01. lsu. edu/faculty/kharms/ K. Harms photo

The Web of Life Complex Causation of Amphibian Deformities & Declines Bowman, Hacker & Cain (2017), Fig. 1. 13

What is Ecology? Ernst Haeckel German scientist, philosopher, physician “oekologie” – combined Greek words for “household” & “knowledge” Photo of Haeckel from Wikimedia Commons

What is Ecology? The scientific study of interactions among organisms and their environments K. Harms photo

Ecology is a Component of Environmental Science – interdisciplinary field that draws concepts, expertise, and tools from natural and social sciences Map of seasonal Gulf Coast hypoxia – the “dead zone” – from Wikimedia Commons

Ecology Can Inform Environmentalism Environmental Movement – "a political and ethical movement that seeks to improve and protect the quality of the natural environment through changes to environmentally harmful human activities" Rachel Carson “No witchcraft, no enemy action had silenced the rebirth of new life in this stricken world [an American town devastated by chemical pesticides]… The people had done it themselves. ” Quote – Encyclopedia Britannica Online; photos of Carson and her 1962 book – Wikimedia Commons

Levels of Biological Organization Principal realm of Ecology Image from Wikimedia Commons

50+ Years of Personal Ecological Research (Rocky inter-tidal, coral reefs, tropical forests, etc. ) Joseph H. Connell Photo of Connell courtesy of Pete Green

Ecological Patterns Observations: Barnacle Inter-tidal Zonation Semibalanus – Larger barnacle, lower in intertidal Chthamalus – Smaller barnacle, higher in intertidal Why? Bowman, Hacker & Cain (2017), Fig. 14. 16

Alternative Mechanistic Hypotheses Natural ecological & evolutionary processes that could have produced the patterns (i. e. , cause-and-effect) Barnacle Inter-tidal Zonation Abiotic influences – Differential physiological tolerances to desiccation or submersion Biotic interactions – Interspecific competition Predation (e. g. , Thais snails prey on Semibalanus)

Testable Predictions Barnacle Inter-tidal Zonation Abiotic influences – Move barnacles outside current zones and performance should decline Biotic interactions – Remove competition and zones should shift Remove predators and zones should shift

Selected Experimental Results Barnacle Inter-tidal Zonation The absence of competitors & predators produced no change in upper distributions For Chthamalus, removing Semibalanus increased downslope survivorship & distribution For Semibalanus, removing Thais increased downslope survivorship & distribution

Mechanistic Explanation / Interpretation Barnacle zonation Connell (1961) Ecology, Fig. 5

Scientific Advancements Observations Jane Goodall and chimp

Scientific Advancements Population size (scaled to max. size attainable) Observations Models (mathematical and computer) Per capita rate of increase Chaotic population growth

Scientific Advancements Observations Models (mathematical and computer) Controlled Experiments (e. g. , laboratory, microcosm, mesocosm) http: //lishaopeng. weebly. com/aquatic-algal-microcosm-experiment. html

Scientific Advancements Observations Models (mathematical and computer) Controlled Experiments (e. g. , laboratory, microcosm, mesocosm) Field Experiments Replicated fuel-manipulation treatments in Louisiana pine savanna; photo courtesy of Jonathan Myers

Scale in Ecology “It is argued that the problem of pattern and scale is the central problem in ecology, unifying population biology and ecosystems science, and marrying basic and applied ecology” S. Levin (1992) Photo of Levin from Princeton U.

Scale in Ecology Spatial & temporal patterns often change with the scale of measurement E. g. , species-area relationship(s) Focus Extent Hubbell (2001) The Unified Neutral Theory of Biodiversity & Biogeography, Fig. 6. 2

Scale in Ecology We seek mechanistic links among patterns and processes across scales E. g. , how can we extrapolate from one scale to another (e. g. , leaf-level gas exchange and photosynthesis forest productivity global climate change)? In other words, what are the relevant details? https: //www. youtube. com/watch? v=jf. SNx. Vqprv. M Photos from Wikimedia Commons