Principles of Ecology Chapter 2

Ecology The study of interactions among organisms and between organisms and their environment.

The Biosphere The portion of the planet in which life exists –Land –Water –Air –8 km above Earth’s surface –11 km below the surface of the ocean

Living vs. Nonliving Abiotic Factors: nonliving factors –Examples? Biotic Factors: living factors –Examples? Ecology studies the interaction of biotic and abiotic.

Levels of Organization Species – group of organisms that interbreed to produce fertile offspring

Levels of Organization Population – group of individuals that belong to the same species and live in the same area –Example: the alligator population of Greenfield Lake

Levels of Organization Communities – groups of populations that live together in a defined area –Example: the Cape Fear River community

Levels of Organization Ecosystem –Organisms and nonliving environment they inhabit

Levels of Organization Biome – group of ecosystems with the same climate and similar communities.

Niche: Organisms “occupation” (where it lives, its place in the food web etc.)Niche: Organisms “occupation” (where it lives, its place in the food web etc.)

Ecological Methods Observing Experimenting Modeling

Community Interactions 1.Competition: compete over resources 2.predation: one organism feeds on another 3.Symbiosis 3.Symbiosis: any relationship where 2 animals live closely together

Types of Symbiosis 1.Mutualism: both species benefit Ex. Flowers & insects 2.Commensalism: one member benefits and the other is neither helped nor harmed ex. Barnacles 3. Parasitism: one organism lives on or in another and harms it. ex. tapeworms

Where does the energy from your favorite foods ultimately come from?

Energy Flow Producers (autotrophs): harness sunlight to produce food

Energy Flow Chemoautotrophs: use energy from chemical compounds (in hydrothermal vents) to produce food

Consumers (heterotrophs) –Herbivores – eat plants

Heterotrophs (continued) –Carnivores – eat meat –Omnivores – eat both plants and animals –Detritivores (Decomposers) – eat dead remains (detritus)

Energy Flow Food Chain –Series of steps in which organisms transfer energy by eating and being eaten

Energy Flow Food Web –The depiction of a network of feeding relationships

Energy Flow Trophic Levels: Each step in a food chain –Producers make up the bottom level –Consumers make up the upper levels –Each level depends on the level below it

Energy Levels Energy Pyramids: amount of energy contained in each trophic level –10% of the energy in one trophic level is transferred to the one above.

Energy Flow Biomass Pyramid: amount of potential food available for each trophic level –Biomass: amount of living tissue Pyramid of Numbers: based on the numbers of individual organisms

Cycles of Matter The water cycle: –All living things require water to survive –Precipitation, transpiration, evaporation etc

Cycles of Matter The Carbon Cycle: –Carbon is the key ingredient of living tissue –Respiration, photosynthesis, feeding, erosion etc.

Cycles of Matter The Nitrogen Cycle –Necessary for amino acids –Nitrogen fixing bacteria on roots “fix” atmospheric nitrogen to be used by plants. –Consumers get nitrogen by eating producers

Limiting Nutrient When an ecosystem is limited by a single nutrient – controls the number of producers –Fertilizers