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POPULATION DYNAMICS. POPULATION DYNAMICS. POPULATION POPULATION DEF?? POPULATION ECOLOGY CONCERNED WITH THE CHANGES IN POPULATION SIZE AND THE FACTORS THAT REGULATE POPULATIONS OVER TIME. POPULATION DYNAMICS. POPULATION ECOLOGY . POPULATION DYNAMICS.
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POPULATION DYNAMICS • POPULATION • POPULATION DEF?? • POPULATION ECOLOGY • CONCERNED WITH THE CHANGES IN POPULATION SIZE AND THE FACTORS THAT REGULATE POPULATIONS OVER TIME
POPULATION DYNAMICS • POPULATION ECOLOGY
POPULATION DYNAMICS • DENSITY AND DISPERSION PATTERNS ARE IMPORTANT POPULATION VARIABLES • POPULATION DENSITY • THE NUMBER OF INDIVIDUALS OF A SPECIES PER UNIT AREA OR VOLUME • IT’S EXTREMELY DIFFICULT TO COUNT ALL THE INDIVIDUALS IN ANY POPULATION, SO SCIENTISTS USE VARIOUS SAMPLING TECHNIQUES • TAG & RECAPTURE METHOD
POPULATION DYNAMICS • DENSITY AND DISPERSION PATTERNS ARE IMPORTANT POPULATION VARIABLES • DISPERSION PATTERN • REFERS TO THE WAY INDIVIDUALS ARE SPACED WITHIN THEIR AREA • 3 MAJOR PATTERNS • CLUMPED • UNIFORM • RANDOM
POPULATION DYNAMICS • IDEALIZED MODELS HELP US UNDERSTAND POPULATION GROWTH • EXPONENTIAL GROWTH MODEL • RATE OF EXPANSION OF A POPULATION UNDER IDEAL CONDITIONS; UNREGULATED GROWTH
POPULATION DYNAMICS • IDEALIZED MODELS HELP US UNDERSTAND POPULATION GROWTH • POPULATION-LIMITING FACTORS AND THE LOGISTIC GROWTH MODEL
POPULATION DYNAMICS • IDEALIZED MODELS HELP US UNDERSTAND POPULATION GROWTH • IDEALIZED MODELS DON’T EXIST IN NATURE!! • POPULATION-LIMITING FACTORS • ENVIRONMENTAL FACTORS THAT RESTRICT POPULATION GROWTH • LOGISTIC GROWTH MODEL • IDEALIZED POPULATION GROWTH THAT IS SLOWED BY LIMITING FACTORS AS THE POPULATION SIZE INCREASES
POPULATION DYNAMICS • LOGISTIC GROWTH MODEL • CARRYINGCAPACITY • THEMAXIMUMPOPULATIONSIZE THAT ANENVIRONMENTCAN SUPPORTAT APARTICULARTIME, WITHNODEGRADATIONTO THEHABITAT
POPULATION DYNAMICS • MULTIPLE FACTORS MAY ACT AS LIMITING AGENTS • COMPETITION FOR LIMITED RESOURCES • FOOD, TERRITORY, MATES, ETC. • INCREASED DISEASE TRANSMISSION • PHYSIOLOGICAL FACTORS ARE IMPACTED BY DENSE POPULATIONS • ABIOTIC FACTORS MAY IMPACT POPULATION SIZE • *SOME POPULATIONS HAVE “BOOM-AND-BUST” CYCLES* • THIS IS NOT FULLY UNDERSTOOD
POPULATION DYNAMICS • WHAT DOES THE LOGISTIC GROWTH MODEL REALLY LOOK LIKE IN A STABLE ENVIRONMENT??
POPULATION DYNAMICS • HUMAN POPULATION GROWTH
POPULATION DYNAMICS • LIFE TABLES TRACK MORTALITY AND SURVIVORSHIP IN POPULATIONS • SURVIVORSHIP CURVES • PLOT THE PROPORTION OFINDIVIDUALS ALIVE AT EACH AGE
POPULATION DYNAMICS • BIRTH AND DEATH RATES AND AGE STRUCTURE AFFECT POPULATION GROWTH • ZERO POPULATION GROWTH (ZPG) IS WHEN BIRTH RATES EQUAL DEATH RATES
POPULATION DYNAMICS • BIRTH AND DEATH RATES AND AGE STRUCTURE AFFECT POPULATION GROWTH • AGE STRUCTURE • THE PROPORTION OF INDIVIDUALS IN DIFFERENT AGE-GROUPS
POPULATION DYNAMICS • TWO IMPORTANT PRACTICAL USES OF POPULATION DYNAMICS INCLUDE • RENEWABLE RESOURCE MANAGEMENT • HARVESTING CROPS WITHOUT DAMAGING THE RESOURCE • MAXIMUM SUSTAINABLE YIELD • HARVESTING AT A LEVEL THAT PRODUCES A CONSISTENT YIELD WITHOUT DAMAGING THE POPULATION
POPULATION DYNAMICS • THAT’S POPULATION ECOLOGY…BUT HOW DO ALL OF THE DIFFERENT POPULATIONS GET ALONG?? • THAT’S COMMUNITY-LEVEL ECOLOGY, AND THAT’S NEXT!!!