Ecosystem
• An ecosystem is a collection of all of the organisms that live in a particular place along with their nonliving or physical environment o School as an ecosystem
Ecology
• The study of interactions among organisms and between organisms and their environment
• Levels: individual organism (Species), population, community, ecosystem, biome, biosphere
Energy Flow
• In ecosystem, energy flows from sun or inorganic compounds to producers (make own food) to consumers (rely on other organisms for food)
• In one direction: Sun → Autotrophs → Heterotrophs o Sunlight is main energy source for life
Autotrophs (Producers) capture energy from sunlight or inorganic compounds
• I.e. plants, certain bacteria, some algae
• Autotrophs either use photosynthesis: CO2 + H2O & light energy → O2 + C6H12O6
• Or chemosynthesis: certain bacteria use chemical energy to produce carbs
Heterotrophs (Consumers) - rely on other organisms for energy and food
• Types: herbivores, carnivores, omnivores, detritivores, decomposers
Energy Flow - Ecosystems o Food Chain – series of steps in which organisms transfer energy by eating and being eaten o Food Web – links together all food chains in an ecosystem o Trophic Level – each step in a food chain or web
Ecological Pyramids – diagram showing the relative amount of energy in each level or a food web or food chain
• Energy pyramids – show how much energy available at ea. Trophic level o 90% used for life processes or lost as heat, 10% passed onto next level
• Biomass pyramid – shows amount of living tissue within each trophic level
• Pyr. Of Numbers – shows relative number of individuals at each level
Cycles of Matter
• Matter is recycled within and between ecosystems (unlike energy)
• Biogeochemical cycles – connect biological, geological, and chemical processes
• i.e: the Water, Carbon, Nitrogen cycles
Summary:
An ecosystem consists of organisms and their nonliving surroundings. Ecology is a field that involves the study of ecosystems and the study of the interactions of organisms with their environment and other organisms. In an ecosystem, energy flows from one direction: from the sun or inorganic compounds to autotrophs to heterotrophs. Autotrophs are organisms that produce their own food. Heterotrophs rely on other organisms from their food. Food chains and webs show how energy is transferred from producers to consumers. Ecological pyramids, such as an energy pyramid, a biomass pyramid, and a pyramid of numbers show the relative amount of energy at each trophic level of a web or chain. Lastly, biogeochemical cycles, such as the water cycle, connect biological, geological, and chemical processes, showing how matter is recycled within and among ecosystems.