ECOSYSTEMS

YOU MUST KNOW… HOW ENERGY FLOWS THROUGH THE ECOSYSTEM BY UNDERSTANDING THE TERMS THAT RELATE TO FOOD CHAINS AND FOOD WEBS THE DIFFERENCE BETWEEN GROSS PRIMARY PRODUCTIVITY AND NET PRIMARY PRODUCTIVITY THE CARBON AND NITROGEN BIOGEOCHEMICAL CYCLES

CONCEPT 55.1 PHYSICAL LAWS GOVERN ENERGY FLOW AND CHEMICAL CYCLING IN ECOSYSTEMS

ECOSYSTEM SUM OF ALL THE ORGANISMS (BIOTIC) LIVING WITHIN ITS BOUNDARIES AND ALL THE ABIOTIC FACTORS THEY INTERACT WITH ENERGY FLOW CANNOT BE RECYCLED SO IT MUST BE CONSTANTLY SUPPLIED TO AN ECOSYSTEM, MAINLY BY THE SUN

PRIMARY PRODUCERS – AUTOTROPHS, SUPPORT ALL OTHER ORGANISMS IN THE ECOSYSTEM HETEROTROPHS – CONSUMERS, CANNOT MAKE THEIR OWN FOOD PRIMARY CONSUMER – HERBIVORES SECONDARY CONSUMERS – CARNIVORES THAT EAT HERBIVORES TERTIARY CONSUMERS – EAT SECONDARY CONSUMERS

DETRITIVORES AKA DECOMPOSERS – GET THEIR ENERGY FROM NONLIVING ORGANIC MATERIAL (DEAD ORGANISMS) CONVERT ORGANIC MATERIALS FROM ALL TROPHIC LEVELS TO INORGANIC COMPOUNDS THAT CAN BE USED BY PRODUCERS NUTRIENTS CYCLE THROUGH ECOSYSTEMS

CONCEPT 55.2 ENERGY AND OTHER LIMITING FACTORS CONTROL PRIMARY PRODUCTION IN ECOSYSTEMS

PRIMARY PRODUCTION – THE AMOUNT OF LIGHT ENERGY CONVERTED TO CHEMICAL ENERGY BY AUTOTROPHS THE AMOUNT OF ALL PHOTOSYNTHETIC PRODUCTION SETS THE SPENDING LIMIT FOR THE ENERGY BUDGET OF THE ENTIRE ECOSYSTEM

THE TOTAL PRIMARY PRODUCTION IS THE SYSTEM’S GROSS PRIMARY PRODUCTION (GPP) SOME GPP MUST BE USED AS FUEL FOR THEIR OWN CELL RESPIRATION NET PRIMARY PRODUCTION (NPP) – EQUAL TO GSS MINUS THE ENERGY USED FOR RESPIRATION (R) BY THE PRODUCERS NPP = GPP - R

EUTROPHIC A LAKE THAT IS NUTRIENT-RICH AND THAT SUPPORTS A VAST ARRAY OF ALGAE REVIEW LAB 12

CONCEPT 55.3 ENERGY TRANSFER BETWEEN TROPHIC LEVELS IS TYPICALLY ONLY 10% EFFICIENT

10% OF ENERGY IS TRANSFERRED FROM PRIMARY PRODUCER TO PRIMARY CONSUMER TO SECONDARY CONSUMER, ONLY 1% OF THE NET PRIMARY PRODUCTION (10% OF 10%) IS AVAILABLE TO SECONDARY CONSUMERS PYRAMIDS OF ENERGY OR BIOMASS ARE USED TO GIVE INSIGHT TO FOOD CHAINS

CONCEPT 55.4 BIOLOGICAL AND GEOLOGICAL PROCESSES CYCLE NUTRIENTS BETWEEN ORGANIC AND INORGANIC PARTS OF AN ECOSYSTEM

BIOGEOCHEMICAL CYCLES – NUTRIENT CYCLES THAT CONTAIN BOTH BIOTIC AND ABIOTIC COMPONENTS CARBON CYCLE – BALANCE BETWEEN THE AMOUNT OF CO2 REMOVED BY PHOTOSYNTHESIS AND ADDED BY CELL RESPIRATION NITROGEN CYCLE – MOVES NITROGEN FROM THE ATMOSPHERE THROUGH THE LIVING WORLD IMPORTANT FOR PLANT GROWTH

MOST OF EARTH’S NITROGEN IS UNUSABLE BY PLANTS AND NEED TO UNDERGO NITROGEN FIXATION, THE CONVERSION OF N2 BY BACTERIA TO FORMS THAT CAN BE USED BY PLANTS NITRIFICATION – PROCESS BY WHICH AMMONIUM (NH4+) IS OXIDIZED TO NITRITE AND THEN NITRATE (NO3-) BY BACTERIA DENITRIFICATION BY BACTERIA RELEASES NITROGEN TO THE ATMOSPHERE

CONCEPT 55.5 HUMAN ACTIVITIES NOW DOMINATE MOST CHEMICAL CYCLES ON EARTH

ACID PRECIPITATION RAIN, SNOW, OR FOG WITH A pH LESS THAN 5.6 THE BURNING OF FOSSIL FUELS RELEASES SULFUR OXIDES AND NITROGEN OXIDES INTO THE AIR OXIDES REACT WITH WATER, FORMING SULFURIC ACID AND NITRIC ACID

BIOLOGICAL MAGNIFICATION TOXINS BECOME MORE CONCENTRATED IN SUCCESSIVE TROPHIC LEVELS OF A FOOD WEB TOXINS CANNOT BE BROKEN DOWN BIOLOGICALLY BY NORMAL CHEMICAL MEANS THEY MAGNIFY IN CONCENTRATION AS THEY MOVE THROUGH THE FOOD CHAIN

GREENHOUSE EFFECT REFERS TO THE ABSORPTION OF HEAT THE EARTH EXPERIENCES DUE TO CERTAIN ATMOSPHERIC GASES CARBON DIOXIDE AND WATER VAPOR INTERCEPT AND ABSORB MUCH REFLECTED INFRARED RADIATION, RE-REFLECTING SOME BACK TOWARD EARTH

GLOBAL WARMING BECAUSE OF THE BURNING OF FOSSIL FUELS, CARBON DIOXIDE LEVELS HAVE BEEN STEADILY INCREASING THIS WARMS UP THE EARTH

OZONE LAYER REDUCES THE AMOUNT OF UV RADIATION PENETRATION FROM THE SUN THROUGH THE ATMOSPHERE CFC’s ERODE THE OZONE LAYER