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Bright blue marble spinning in space. Ecology. Studying organisms in their environment. biosphere. ecosystem. community. population. organism. Interacting with the environment. Biotic environment prey (food) competitors predators, parasites, disease Abiotic environment sunlight
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Studying organisms in their environment biosphere ecosystem community population organism
Interacting with the environment • Biotic environment • prey (food) • competitors • predators, parasites, disease • Abiotic environment • sunlight • temperature • water • soil
organism population community ecosystem biosphere Population Ecology
Life takes place in populations • Population • group of individuals of same species in same area at same time • rely on same resources • interact • interbreed Population Ecology: What factors affect a population?
Devil’s hole pupfish Iiwi Hawaiian bird Iriomote cat Socorro isopod New Guinea tree kangaroo Catalina Island mahogany tree Northern white rhinoceros At risk populations • Endangered species • limitations to range / habitat • places species at risk
Population Size • Changes to population size • adding & removing individuals from a population • birth • death • immigration • emigration
Exponential growth rate • Characteristic of populations without limiting factors Whooping crane coming back from near extinction African elephant protected from hunting
Regulation of population size • Limiting factors • food supply, competition • predators • disease • abiotic factors • sunlight • temperature • rainfall
Logistic rate of growth • Can populations continue to grow exponentially? Of course not! no natural controls K =Carryingcapacity effect of natural controls
10 8 Number of breeding male fur seals (thousands) 6 4 2 0 1915 1925 1935 1945 Time (years) Carrying capacity • Maximum population size that environment can support with no breakdownof habitat • varies with changes in resources
Population of… China: 1.3 billion India: 1.1 billion Significant advances in medicine through science and technology Industrial Revolution Human population growth adding 82 million/year What factors have contributed to this exponential growth pattern? 20056 billion Is the human population reachingcarrying capacity? Bubonic plague "Black Death" 1650500 million