LECTURE TWENTY-SIX

OXYGEN IS A MAJOR NON-LIVING COMPONENT

OXYGEN LEVELS ARE LOW AT THE BOTTOM OF A BODY
OF WATER, AND HIGHER AT THE TOP
HOT WATER HOLDS LESS OXYGEN THAN COLD WATER

STRICT AEROBIC ORGANISMS REQUIRE OXYGEN
STRICT ANAEROBIC ORGANISMS DIE IN OXYGEN
FACULTATIVE AEROBIC ORGANISMS SURVIVE WITH
OR WITHOUT OXYGEN


TEMPERATURE IS IMPORTANT TO ORGANISMS ALSO
THERMOPHILS LIVE AT HIGH TEMPERATURES
PSYCHROPHILS LIVE AT LOW TEMPERATURES
MESOPHILS LIVE AT MID-RANGE TEMPERATURES




THE NON-LIVING ASPECTS ARE LIMITING FACTORS

THE LIMIT CAN BE ABSOLUTE OR RELATIVE




ALL OF THE ORGANISMS IN AN ECOSYSTEM MAKE UP
THE COMMUNITY OF THE ECOSYSTEM

THE COMMUNITY IS MADE UP OF POPULATIONS

A POPULATION IS A GROUP OF ORGANISMS OF THE
SAME SPECIES THAT ARE LIVING AND BREEDING
TOGETHER

POPULATIONS INCREASE EXPONENTIALLY, NOT
ADDITIVELY

POPULATIONS DO NOT INCREASE INDEFINITELY BUT
REACH THE CARRYING CAPACITY FOR THE ECOSYSTEM
AND THEN LEVEL OFF




TROPHIC RELATIONSHIPS ARE FOOD OR NOURISHMENT RELATIONSHIPS IN THE COMMUNITY

A FOOD CHAIN IS THE TRANSFER OF FOOD ENERGY
THROUGH A SERIES OF ORGANISMS WITH REPEATED
EATING AND BEING EATEN




PRODUCER ORGANISMS ARE ALWAYS GREEN PLANTS
PRIMARY CONSUMERS ARE ALWAYS HERBIVORES
SECONDARY CONSUMERS ARE ALWAYS CARNIVORES
HIGHER LEVEL CONSUMERS ARE ALSO CARNIVORES




80% TO 90% OF FOOD ENERGY IS LOST AS HEAT
WHEN IT PASSES FROM ONE LEVEL TO ANOTHER




BIOLOGICAL MAGNIFICATION IS THE INCREASE IN
THE CONCENTRATION OF MATERIALS AS THEY PASS
FROM ONE LEVEL OF A FOOD CHAIN TO ANOTHER




INDIVIDUAL FOOD CHAINS ARE INTERLINKED TO
FORM FOOD WEBS




THE CHEMCIAL COMPONENTS OF ECOSYSTEMS CYCLE
IN CHARACTERISTIC ROUTES CALLED
BIOGEOCHEMICAL CYCLES

NON-LIVING              RESERVOIR POOL

ORGANISMS               EXCHANGE POOL

HYDROLOGICAL CYCLE OR WATER CYCLE