Ecology --- primary definition The scientific study of how organisms interact with the natural world.

Ecology --- important distinctions Level of focus Relations with environment Definition of “organism” “Scientific”

Alternative/Equivalent definitions The study of what determines the distribution and abundance of organisms. The study of the structure and function of ecosystems. The study of the anatomy and physiology of ecosystems.

Chemistry Relationships with other fields Physics Ecology Conservation Ecology Pollution Ecology Restoration Ecology Environmental Science

When is ecology helpful? Figuring out what is most important for: –Minimizing impacts –Managing exploitation –Preserving and restoring

Conceptual Framework of Ecology Levels of organization Habitat, niche, environment Constraints on the system –Physical and Chemical –Dynamic –Evolutionary

Organism level How are the distinctive characteristics of the behaviour (or physiology or life history or morphology) of this organism adaptive in its natural environment? Population level What determines the average abundance (or rate of growth, ability to recover, or stability) of this population?

Guild level What determines how many species coexist in this feeding guild? Community level What determines how many guilds coexist or their relative abundance in this community?

Ecosystem level What determines the abundance or biomass of plants in this community? What would be the impact of harvesting top predators in this community? Are diverse ecosystems more stable than more simple ones?

Conceptual Framework of Ecology Levels of organization Habitat, niche, environment Constraints on the system –Physical and Chemical –Dynamic –Evolutionary

Habitat An organism’s surroundings Niche Range of conditions tolerated Role or “profession” in the system Both are subjective from point of view of the organism

Environment Variation is universal in time and space. Subjectively perceived Consists of two components Periodic or predictable Irregular or unpredictable