Principles of Ecology(LSU BIOL 4253, Section 3, Fall 2015)

Composite satellite image (“Blue Marble 2012”) from Wikimedia Commons

A312 Life Sciences Annexkharms@lsu.edu

Dr. Kyle E. Harms

http://www.kharms.biology.lsu.edu

K. Harms photo

Complex Causation of Amphibian Deformities & Declines

The Web of Life

Cain, Bowman & Hacker (2014), Fig. 1.13

Ernst HaeckelGerman scientist, philosopher, physician

“oekologie” – combined Greek words for “household” & “knowledge”

What is Ecology?

Photo of Haeckel from Wikimedia Commons

The scientific study of interactions among organisms and their environments

What is Ecology?

K. Harms photo

Ecology is a Component of Environmental Science

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

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"

Ecology Can Inform Environmentalism

Quote – Encyclopedia Britannica Online; photos of Carson and her 1962 book – Wikimedia Commons

Rachel Carson

Image from Wikimedia Commons

Levels of Biological Organization

Principal realm of Ecology

Joseph H. Connell

50+ Years of Personal Ecological Research(Rocky inter-tidal, coral reefs, tropical forests, etc.)

Photo of Connell courtesy of Pete Green

Ecological Patterns

Cain, Bowman & Hacker (2014), Fig. 12.9

Observations: Barnacle Inter-tidal Zonation

Semibalanus – Larger barnacle, lower in intertidal

Chthamalus – Smaller barnacle, higher in intertidal

Why?

Barnacle Inter-tidal Zonation

Abiotic influences –

Differential physiological tolerances to desiccation or submersion

Biotic interactions –

Interspecific competition

Predation (e.g., Thais snails preyon Semibalanus)

Alternative Mechanistic HypothesesNatural ecological & evolutionary processes that

could have produced the patterns (i.e., cause-and-effect)

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

Barnacle zonation

Mechanistic Explanation / Interpretation

Connell (1961) Ecology, Fig. 5

Observations

Scientific Advancements

Jane Goodall and chimp

Jane Goodall

ObservationsModels (mathematical and computer)

Scientific Advancements

Chaotic population growth

Per capita rate of increase

Pop

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size

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inab

le)

ObservationsModels (mathematical and computer)

Controlled Experiments (e.g., laboratory, microcosm, mesocosm)

Scientific Advancements

http://lishaopeng.weebly.com/aquatic-algal-microcosm-experiment.html

ObservationsModels (mathematical and computer)

Controlled Experiments (e.g., laboratory, microcosm, mesocosm)Field Experiments

Scientific Advancements

Replicated fuel-manipulation treatments in Louisiana pine savanna; photo courtesy of Jonathan Myers

Photo of Levin from Princeton U.

“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)

Scale in Ecology

E.g., species-area relationship(s)

Focus

Extent

Hubbell (2001) The Unified Neutral Theory of Biodiversity & Biogeography, Fig. 6.2

Spatial & temporal patterns often change with the scale of measurement

Scale in Ecology

Photos from Wikimedia Commons

E.g., how can we extrapolate from one scale to another (e.g., leaf-level gas exchange and photosynthesis

forest productivity global climate change)?

We seek mechanistic links among patterns and processes across scales

Scale in Ecology