2 EcologyEcology – the study of interactions among organisms and between organisms and their environmentInterdependence – dependence of every form of life on other living things and natural resources (air, water, land) in its environment
3 Levels of Organization Biosphere – largest, portions of planet where life exists (land, H2O, air)8 km above to 11 km belowBiome – group of ecosystems with same climate (temp. and rainfall)Ecosystem – collection of all organisms in a particular place together with the abiotic (physical) environment.
4 Levels of Organization Community – groups of different populations that live together in a defined area.Population – groups of individuals of same species in same area.Species – group of organisms so similar that they can mate and produce fertile offspring.
6 Biotic and Abiotic Factors Biotic – livingPlants, Animals ,Mold, Fungi, Bacteria, ProtistAbiotic – NonlivingSunlight, soil, wind, water, temperatureHabitat – the area where an organism lives; includes both biotic and abiotic factors.
7 Ecological Methods Observation – 1st step to designing an experiment Experiment – test hypotheses; imitate & manipulateModeling – make models based on observation & experimentHelps make future predictions
8 3.2 ENERGY FLOW (Autotrophs and Heterotrophs) One of the most important factors to determine capacity to sustain life is Energy Flow
9 Autotrophs (producers) Can trap light energy to produce food (organic molecules)PlantsSome protistsSome bacteriaPhotosynthesis – captures solar energy and converts it to chemical energy6CO2 + 6H2O C6H12O6 + 6O2Chemosynthesis – Chemical energy used to produce carbohydratesSUN
10 Heterotrophs (consumers) Can’t trap energy directly; must acquire it from other organismsHerbivores – plantsCarnivores – animalsOmnivores – bothDetritivores – remains of dead plants & animalsDecomposers – break down organic matter
11 3.2 Energy Flow in Ecosystems Food Chains and Food Webs
12 Food Chains and Food Webs SUN Autotrophs HeterotrophFood Chain – energy trapped by producers passed on when organisms eat and are eatenFood Web – relationship more complex than a chain
13 Trophic Levels and Ecological Pyramids Trophic Levels – each step in a food chain/webEx: producers, then consumersEcological Pyramids – shows relative amount of energy at each level (10% rule)Biomass – total amount of living tissue within a trophic level
18 The Carbon CycleVolcanoes, respiration, fossil fuels, and decomposition add CO2 to atmosphere.Plants take CO2 and make carbohydratesPlants are eaten by animals and carbohydrates are passed through the food chain.As the animal breathes and eventually dies and decomposes CO2 is return to atmosphere.
20 Water Cycle Water enters the atmosphere by: Evaporation – water changes from a liquid to a gasTranspiration – Evaporation through leavesAs water rises it cools condenses into tiny droplets that form clouds.Droplets returns to Earth as precipitation.Water enters the rivers, ground water, ocean or plant roots to restart cycle.
22 Nitrogen Cycle Nitrogen gas makes up 78% of atmosphere Nitrogen Fixation: bacteria take nitrogen gases and turn it into ammonia, nitrite, and nitrate.Plants and animals use nitrate to make amino acids.Animal dies and decomposes returning nitrates to the soil.Denitrification: other bacteria convert nitrates into nitrogen gas.
23 The Phosphate Cycle Phosphate – parts of DNA/RNA Found in rocks that are worn downWashes into rivers/streams/oceans for marine organismsTaken in by plants and turned into organic compounds
24 Nutrient LimitationPrimary Productivity – the rate at which organic molecules are created by producersIf nutrients are in short supply, they are called LIMITING NUTRIENTSEx: Nitrogen is often limiting in water; if there is suddenly as input of N (fertilizer runoff), organisms can grow rapidly (Algal Bloom)
25 Discussion questions: How many stops can you make on your trip?Will your journey ever end?Was everyone’s journey the same? Why not?What would happen if a farmer used too much fertilizer? (In this game, that would mean that everyone started from the fertilizer station at the same time.)Livestock farming creates a large amount of animal waste. How would this affect the nitrogen cycle?