PLB 115 1st Edition Lecture 11Outline of Last LectureII. Photosynthesis overviewa. Photosynthesisb. Events: Light-capturing, Light-dependent, Light-independentIII. Light-capturing eventsa. Accessory pigmentsIV. PhotosystemsV. Light-dependent eventsVI. Light-independent eventsVII. Light Dependent Reactions BasicsVIII. Electron Transport Chain & ATP SynthesisIX. Interactions of PSII & PSIX. Plant MetabolismOutline of Current LectureI. Ecology II. Biotic FactorsIII. Abiotic FactorsIV. Trophic levelsV. Food chainVI. Energy pyramidVII. Pyramid of numbersVIII. Biomass pyramidIX. “Nature’s Recycling”X. Carbon cycleXI. Hydrologic cycleXII. Nitrogen cycleXIII. Nitrogen in SoilXIV. Phosphorus CycleXV. Ecosystem productivityXVI. Manipulation of EcosystemsXVII. Human NutritionThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Current LectureEcosystem DynamicsEcology: Branch of biology that studies relationship between organisms & their environments (anything affecting an organism during its lifetime- living & non-living)Ecologists: Scientists that study organismal interactions at different levels- Individual organisms & how they interact with their environment- Populations (groups of organisms of same species) & how they change over time- Communities (interactions between different species)- Ecosystems (interacting groups of organisms & how they interact with abiotic factors in their environment)Biotic factors: Living things o Ex: Other members of population Pathogens, parasites, predators, prey Shade trees, animal soundsAbiotic factors: Physical things (non-living)o Ex: Atmosphere, air (wind), sunlight, temperature, waterExamples of Abiotic & Biotic factors- Temperature of the water (abiotic) is affected by the presence of trees (biotic factor)- The amount of food in the stream (biotic)- The composition of the stream bed affects how fast the stream flows and the oxygen content of the water (abiotic)- Minerals in the soil (abiotic)- The amount of sunlight or rainfall hitting the plant (abiotic) - Predators and pathogens (biotic)Trophic LevelsOrganisms fit into different categories (trophic levels) based on how they satisfy their energy requirements - Flow of energy in ecosystem begins with sun’s sunlight given to producers that capture its energy & produce organic matter through photosynthesis- Consumers eat this organic matter made by the producers (by eating producers)- Decomposers break down dead organic matter & waste productsFood chain- 1st trophic level: Producers make own energy from sunlight- 2nd trophic level: Primary Consumers: Herbivores that consume producers- 3rd trophic level: Secondary Consumers: (Primary Carnivores) Carnivores that eat herbivores- 4th trophic level: Tertiary Consumers (Secondary Carnivores) Carnivores that eat other carnivoreso Omnivores: Eat animals (Carnivore) & plants (Herbivore)= (most) Humans Where they fit in food chain depends on what they’re eating the mosto Decomposers: Get energy from converting non-living organic matter to simple inorganic molecules to be re-used by producers (break down dead organisms & wastes) Bacteria, fungiEnergy PyramidShows energy flow through trophic levels Relationship between trophic levels are based on- The amount of energy at each trophic level - The number of organisms at each trophic level - The mass of organic matter (biomass) at each trophic level***REMEMBER THE LAWS OF THERMODYNAMICS***Energy is not created or destroyed & when it is converted from one form to another, most (90%)of this energy is lost to the atmosphere as heat from chemical reactionsPyramid of NumbersEcologists simply count the number of organisms at each trophic levelPyramid shaped b/c: There are more primary producers than consumers & fewer secondary consumers than primary consumers- If organisms are of different size pyramid is uneven (not pyramid)o Ex: One tree (producer) supports hundreds of insects (herbivores)Biomass PyramidOrganisms at each trophic level are weighed (90% loss at each level)Uneven (no) Pyramid shape b/c: If organisms have greatly different life spans- Ex: Phytoplankton cells divide rapidly and are consumed quickly by longer-lived animals that eat the phytoplanktonNature’s Recycling- Amount of matter making up the earth is relatively constant - Organisms temporarily incorporate atoms into their structure All of the building blocks of organic matter (Carbon, nitrogen, hydrogen, oxygen, phosphorus) are recycled by decomposers that break them down & release inorganic material to be re-usedCarbon CycleCarbon (inorganic molecule) from atmosphere is captured & converted to organic molecules & released back into atmosphere- Producers: Carbon dioxide gas is used by plants in photosynthesis to build organic molecules- Consumers: Eat organic molecules, release carbon dioxide back into the atmosphere as aresult of respiration- Decomposers: Organic molecules still in organisms after death & in waste products is released by decomposers through respirationHydrologic CycleWater in oceans, lakes, rivers, & soil evaporates into the atmosphere- Plants absorb water (for photosynthesis) from the soil and release it into the atmosphere via transpiration- Photosynthesiso Hydrogen from the breakdown of water molecules is incorporated into organic moleculeso Oxygen from the breakdown of water molecules is released into the atmosphere at end of cycle- Water vapor in atmosphere condenses into rain/ snow- Rain or snow gets absorbed into land (soil/ground water) & rest of it goes into oceans, lakes, streamsNitrogen CycleNitrogen is necessary to build proteins and nucleic acids but nitrogen gas cannot be utilized by most organisms (must be converted to nitrates -NO3 or ammonia NH3)- Nitrogen fixing bacteria (live in soil when free-living/symbiotic live with some plant roots): Convert nitrogen gas into ammonia- Producers: Use ammonia & nitrate to make nitrogen-containing organic molecules (proteins, DNA)- Consumers: Get nitrogen from proteins in their food & release it as ammonia, urea, or uric acid- Decomposers: Break down nitrogen-containing organic molecules (urea)o Nitrifying bacteria convert ammonia (NH3) to nitrite (-NO2), which is converted by other bacteria to nitrate (-NO3), which can be used by plantso Denitrifying bacteria convert nitrites (-NO2) back into nitrogen gas (N2) and release it into the