Ecology and the Biosphere Notes

Lecture Objectives:

• Define ecology and its branches.
• Describe trophic levels in a food chain.
• Compare and contrast food chains and food webs.

Ecological Systems

Definitions

• Ecology: The branch of biology studying the relationships between living organisms and their environment.
• Organismal Ecology: Study of individual organism's behavior, morphology, and physiology in response to environmental challenges (adaptations).
• Populational Ecology: Study of factors altering and impacting the genetic composition and size of populations.
• Community Ecology: Study of interactions within and between species in a community.
• Ecosystem Ecology: Study of how the ecosystem works, including interactions between biotic (living) and abiotic (nonliving) components.
• Ecosystem: Composed of all biotic (living) things in an area along with the abiotic (nonliving) components of that area.
• Biosphere: All parts of Earth inhabited by life.
• Biogeography: Study of the geographic distribution of living things and the abiotic factors (temperature, rainfall) affecting their distribution.

Food Chain vs. Food Network

• All ecosystems have:
  • Producers: Autotrophs
  • Primary Consumers: Consume producers
  • Secondary and Tertiary Consumers

Relative Energy Content in Trophic Levels

• Each trophic level has less energy available and supports fewer organisms at the next level.

Food Chain

• A linear sequence of organisms through which nutrients and energy pass: primary producers, primary consumers, and higher-level consumers.
• Each organism occupies a trophic level.

Food Web

• A graphic representation of a holistic, nonlinear web of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics.