Ecology and Environmental Systems

Ecology as a Scientific Endeavor

• Natural systems do not always return to their original state after a disturbance, and random perturbations can play a significant role.
• Different communities can form in the same area under similar environmental conditions.
• Ecological interactions are more complex than previously thought, with no linear relationships.
• Events in nature are interconnected, and a change in one part of an ecological system can alter other parts.

Environmental Science

• Focuses on how people affect the environment and how to address environmental problems.
• Incorporates concepts from the natural sciences and the social sciences.

Key Terms

• Adaptation: A feature of an organism that improves its ability to survive or reproduce in its environment.
• Natural Selection: An evolutionary process in which individuals with particular traits survive or reproduce at a higher rate than others due to those characteristics.
• Producer (Autotroph): An organism that uses energy from an external source to produce its own food without eating other organisms or their remains.
• Consumer (Heterotroph): An organism that obtains its energy by eating other organisms or their remains.
• Net Primary Production (NPP): The amount of energy that producers fix through photosynthesis or other means, minus the amount they use in cellular respiration.
• Nutrient Cycle: The cyclic movement of a nutrient between organisms and the physical environment.

Ecological Scales

• Spatial Scales: The size of the study, ranging from small (e.g., soil microorganisms) to large (e.g., atmospheric pollutants).
• Temporal Scales: The time frame of the study, ranging from short (e.g., leaf response to sunlight) to long (e.g., species change over geologic time).
• Ecologists study interactions across many levels of organization, often emphasizing individuals, populations, communities, or ecosystems.
• Ecological studies include biotic and abiotic factors of natural systems.
• Every ecological study addresses events at some scales but ignores events at other scales.

Ecological Hierarchy

• Individuals: Studying a specific individual that lives in a particular area.
• Population: A group of individuals of a single species that live in a particular area and interact with one another.
• Community: An association of populations of different species in the same area.
• Ecosystem: A community of organisms and their physical environment, including biotic and abiotic factors.
• Landscapes: Areas that include multiple ecosystems.