Topic 1: Systems SYSTEM: an assemblage of parts and their - PDF document

Environmental Systems Mr G’s Environmental Science www.sciencebitz.com 1 Topic 1: Systems • SYSTEM: an assemblage of parts and their relationship forming a functioning entirety or whole. 2 Topic 1: Systems • 1970’s James Lovelock proposes the GAIA hypothesis • The planet acts like a single biological being made up of individual and interconnected units • A SYSTEM 3 Physical Climate System Climate Atmospheric Physics/Dynamics Change Sun Terrestrial Ocean Dynamics energy/moisture Strotspheric Chemistry/ External Forcing Human Activities Dynamics Global Soil CO 2 Moisture Land Marine Terrestrial Use Volcanoes Biogeochemistry Ecosystems CO 2 Tropospheric chemistry Biogeochemical System Polluntants 4

Topic 1: Systems • Systems involve: Inputs of Water, Carbon Dioxide Light energy is trapped and Sunlight by the chlorophyll inside the chloroplasts • Inputs • Outputs • Processes Energy is released, splitting Oxygen is realesed water into hydrogen and to the atmosphere oxygen 5 The hydrogen combines with carbon dioxide to make glucose Topic 1: Systems • Individual systems can be sub-units of bigger systems Inputs of Water, Carbon Dioxide Light energy is trapped and Sunlight by the chlorophyll inside the chloroplasts • A food chain includes photosynthesising plants Energy is released, splitting Oxygen is realesed to the atmosphere water into hydrogen and oxygen The hydrogen combines with carbon dioxide to make glucose 6 Topic 1: Systems • All systems include inputs, processes and outputs Input Output Input Output Input Output Process Process Process 7 Topic 1: Systems 1.1.2: Types of System • Open Systems • Closed Systems • Isolated Systems 8

Topic 1: Systems 1.1.2: Types of System Open Systems • exchange matter and energy with its surroundings. 9 Topic 1: Systems 1.1.2: Types of System Light Energy Closed Systems From the Sun • exchange energy but not matter. Long wave energy (heat) returned to space 10 Topic 1: Systems 1.1.2: Types of System Closed Systems • Biosphere 2 11 Topic 1: Systems 1.1.2: Types of System Isolated Systems • An isolated system exchanges neither matter nor energy. • Isolated systems do not exist naturally • Possible to think of the entire Universe as an 12 isolated system

Topic 1: Systems 1.1.3: Energy in Systems Energy in all systems is subject to the Laws of Thermodynamics 13 Topic 1: Systems 1.1.3: Energy in Systems The First Law: • Energy is neither created Incoming solar radiation (light energy) is trapped by plants and Consumers (herbivores) eat the plants (producers) and the stored chemical Consumers (carnivores) eat other consumers (herbivores) and the converted to sugars (stored chemical energy) No energy has been created or destroyed in the food chain it has only energy gets passed up the food chain stored chemical energy gets passed up the food chain again nor destroyed.. moved or changed form • Energy can only change from one form to another • Often called: The Law of Conservation of energy 14 Topic 1: Systems 1.1.3: Energy in Systems The First Law: • Energy is neither created nor destroyed.. • Of the sunlight falling on Earth not all of it is used for photosynthesis. 15 Topic 1: Systems 1.1.3: Energy in Systems The Second Law: • The entropy of an isolated system not in equilibrium will tend to increase over Heat generated Heat generated Heat generated time during work during work during work e.g. respiration e.g. respiration e.g. respiration • Energy conversions are never efficient and the more conversions in a system the greater the total inefficiency 16

Topic 1: Systems 1.1.3: Energy in Systems Heat The Second Law: • Can be thought of as a Input Energy Useful Energy simple word equation Work • Energy = Work + Heat (and other waste products) • Or the spreading out of Conversion energy process 17 Topic 1: Systems 1.1.4: Equilibria Open systems tend to exist in a state of balance 18 Topic 1: Systems 1.1.4: Equilibria Two types of Equilibrium • Static • Dynamic 19 Topic 1: Systems 1.1.4: Equilibria • Static: Where components of the system remain constant over a long period of time 20

Topic 1: Systems 1.1.4: Equilibria 80 Number of pelts (1000s) • “Dynamic”: 60 Difficult concept 40 A system is in a steady state because the inputs and 20 outputs that affect it approximately balance over a long period of time 0 1900 1905 1910 1915 1920 Year Snowshoe Hare Lynx 21 Topic 1: Systems 1.1.5: Feedback A system are continually affected by and react to information (stimuli) The final outcome of the process is governed by feedback • Negative • Positive 22 Topic 1: Systems 1.1.5: Feedback 80 Negative feedback ) s 0 • tends to damp down, 0 60 0 neutralize or counteract any 1 ( s deviation from an equilibrium, t l 40 e and promotes stability . p f o r 20 e Prey population b Prey population falls grows m u 0 N More food More food Less food Less food 1900 1905 1910 1915 1920 Less hunting Less hunting More hunting More hunting Year Snowshoe Hare Lynx Predator population Predator population falls grows 23 Topic 1: Systems 1.1.5: Feedback Higher temperatures Positive feedback More heat trapped Land and sea • Amplifies or increases by atmosphere temperatures rise change; it leads to exponential deviation away from an equilibrium. Wetter Atmosphere Increased evaporation More water vapour 24

Topic 1: Systems 1.1.6: Transfers and Transformations Both Material and Energy move or flow through ecosystems • A transfer is when the flow does not involve a change of form • A transformation is a flow involving a change of form • Both types of flow use energy - transfers being simpler use less 25 Topic 1: Systems 1.1.6: Transfers and Transformations Both Material and Energy move or flow through ecosystems 26 Topic 1: Systems 1.1.6: Transfers and Transformations Both Material and Energy move or flow through ecosystems 27 Topic 1: Systems 1.1.6: Transfers and Transformations Both Material and Energy move or flow through ecosystems 28

Topic 1: Systems 1.1.6: Transfers and Transformations Both Material and Energy move or flow through ecosystems Transfers can involve: • The movement of material through living organisms (carnivores eating other animals) • The movement of material in a non-living process (water being carried by a stream) • The movement of energy (ocean currents transferring heat) 29 Topic 1: Systems 1.1.6: Transfers and Transformations Both Material and Energy move or flow through ecosystems Transformations can involve: • Matter (glucose converted to starch in plants) • Energy (Light converted to heat by radiating surfaces) • Matter to energy (burning fossil fuels) 30 Topic 1: Systems 1.1.7: Flows and Storages Both energy and matter flows (inputs and outputs) through ecosystems but at times is also stored (stock) within the ecosystem: 31