I. What is Ecology?
A. Definition:
The study of the interactions of organisms with one another and with their environment. - Ricklefs Glossary
The scientific study of the distribution and abundance of organisms and their interactions with the environment.
B. Biological Scales
These interactions between organisms and the environment play out across all biological scales from the organism up.
Individuals interacting with environment: harvesting energy, excreting waste, tolerating abiotic conditions.
Populations of individuals: distribution in space/time/demography/genetics, rate of reproduction/death
Communities of populations: diversity, interactions of predation, competition, mutualism
Ecosystems: including the flux of energy and matter through non-living reservoirs
Biosphere: the totality of life and its effects on energy balance and flux through Earth systems (atmosphere, lithosphere, etc.)
C. Ecological Roles
These interactions often involve the flow of energy and matter (and information through communication) between organisms, populations, communities, and ecosystems within the biosphere.
Carnivorous plants
D. Effects: Distribution and Abundance
These interactions can determine the distribution and abundance of organisms across space (where they live at a given time) and through time (when in the ecological development of a community they live).
- developmental changes at the individual level
- changes in abundance, birth/death rates, genetic structure at a populational level
- changes in community composition over time: succession
- evolutionary changes over geologic time
II. Why is Ecology Important?
A. Pragmatic Issues
1. Humans are as dependent as other organisms on "the environment"
- nutrient cycling (decomposition/ release of 'fertilizers')
- atmospheric and climatic regulation (maintaining climate and oxygen levels fit for human existence)
- water and air waste treatment
- food, shelter, and energy (coal, timber)
- recreation and aesthetic value
The cost of replacing these services with man-made constructs has been estimated at 33,268,000,000,000,000/year. Total Gross National product of World is around 30 trillion.
So, that's what "nature" does; it might be important to understand how these systems operate and respond to change.
2. Humans have always affected these systems
- In the past, humans affected local ecosystems and were never able to sustain an equilibrium with their environment. They either moved (Anasazi of U.S.), or went extinct (colonists of Easter Island), or expanded and drew resources from elsewhere as imports. Now that we are affecting the interactions on a global scale and there is no where else "to go", understanding ecological limitations and human impacts becomes a bit more urgent. ‘Extensification’ is using more space; ‘intensification’ is using existing space more intensively.
- Human population has increased 6x in 150 years.
- Now, Global effects: Human Population uses:
40% of primary productivity (E) - massive extinction is a predictable consequence
50% of the freshwater on the planet
83% of land surface has been affected by humans – we are a geological force.
Affect biogeochemical cycles: greenhouse gases, etc. Nobel Prize in chemistry-1996-Scientists demonstrating Greenhouse Effect
Human populations interact with other populations (parasites, prey) and these interactions can be modeled by general ecological theories (spread of AIDS by a few promiscuous people).
B. Sustainability
Brundtland Commission of the U.N. - Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
The agricultural revolution, and the industrial revolution, have allowed humans to exploit resources at huge spatial scales and rapid temporal scales, and we are affecting the way the planet functions. The earth is a “human-dominated system”. The rates at which we are harvesting resources exceeds their rate of replacement – it is not sustainable. How do we create a sustainable system?
- mimicry. A sustainable system already exists – the natural world. We need to study it and learn from it, to see how the natural world achieved sustainability.
C. Biodiversity
a. Utilitarian value:
We use other species as physiological models, and as sources of compounds for drugs and other materials; in addition to recreational use (hunting, fishing) which has a serious economic impact. Chemicals have been isolated from Poison Dart Frogs that is a more potent pain-killer than morphine. Taxol, which was isolated from Yew trees has anti-cancer properties.
- THE LOSS OF GENETIC INFORMATION IS FOREVER.
b. Ecological value:
Diverse communities are more productive and more resistant to change than less diverse communities. We depend on this productivity. Resistance to change means they are more stable – more sustainable over time.
c. Asthetic/Inherent value:
Are we emotionally enriched by it? Do we have an obligation to assist species imperiled by our actions?
And that’s why every biology major must take ecology, and why every FU student must take a course in sustainability…
Study Questions:
1) Define ecology.
2) Describe two reasons it is an important discipline to understand.
3) Describe three reasons why the preservation of diversity is important.
4) What scales of biological organization are studied in ecology? Name a measurement that you can make at one scale that you cannot make at other scales.
5) How has the distribution and abundance of humans changed over the last 500 years?
6) In particular, most growth has occurred since the industrial revolution. Why? Relate this to extensification and intensification.
7) How do two of your particular actions today affect other species? How do the actions of 2 other species affect you?