The J–shaped curve of exponential growth is characteristic of some populations that are introduced into a new or unfilled environment or whose numbers have been drastically reduced by a catastrophic event and are rebounding. The graph illustrates the exponential population growth that occurred in the population of elephants in Kruger National Park, South Africa, after they were protected from hunting. After approximately 60 years of exponential growth, the large number of elephants had caused enough damage to the park vegetation that a collapse in the elephant food supply was likely, leading to an end to population growth through starvation. To protect other species and the park ecosystem before that happened, park managers began limiting the elephant population by using birth control and exporting elephants to other countries.
The population doubled to 1 billion within the next two centuries, doubled again to 2 billion between 1850 and 1930, and doubled still again by 1975 to more than 4 billion. The global population now numbers over 6 billion people and is increasing by about 73 million each year. The population grows by approximately 201,000 people each day, the equivalent of adding a city the size of Amarillo, Texas, or Madison, Wisconsin. Every week the population increases by the size of San Antonio, Milwaukee, or Indianapolis. It takes only four years for world population growth to add the equivalent of another United States. Population ecologists predict a population of 7.3–8.4 billion people on Earth by the year 2025.
We consume more than just food: water, energy, space/habitat
Bright blue marble floating in space Ecology Chapter 50 Our first power point! Aren't you excited??
Tropical rainforest distribution : equatorial precipitation : very wet temperature : always warm characteristics : many plants & animals, thin soil
Savanna distribution : equatorial precipitation : seasonal, dry season/wet season temperature : always warm characteristics : fire-adapted, drought tolerant plants; herbivores; fertile soil
Desert distribution : 30°N & S latitude band precipitation : almost temperature : variable daily & seasonally, hot & cold characteristics : sparse vegetation & animals, cacti, succulents, drought tolerant, reptiles, insects, rodents, birds
Temperate Grassland distribution : mid-latitudes, mid-continents precipitation : seasonal, dry season/wet season temperature : cold winters/hot summers characteristics : prairie grasses, fire-adapted, drought tolerant plants; many herbivores; deep, fertile soil
Coniferous Forest (Taiga) distribution : high-latitude, northern hemisphere precipitation : adequate to dry (temperate rain forest on coast) temperature : cool year round characteristics : conifers; diverse mammals, birds, insects, etc.
Arctic Tundra distribution : arctic, high-latitude, northern hemisphere precipitation : dry temperature : cold year round characteristics : permafrost, lichens & mosses, migrating animals & resident herbivores
Alpine Tundra distribution : high elevation at all latitudes precipitation : dry temperature : cold year round characteristics : permafrost, lichens, mosses, grasses; migrating animals & resident herbivores
Community of organisms plus the abiotic factors that exist in a certain area
Nutrient cycling Decomposition connects all trophic levels
Carbon cycle CO 2 in atmosphere Diffusion Respiration Photosynthesis Photosynthesis Plants and algae Plants Animals Industry and home Combustion of fuels Animals Carbonates in sediment Bicarbonates Deposition of dead material Deposition of dead material Fossil fuels (oil, gas, coal) Dissolved CO2
Nitrogen cycle Birds Herbivores Plants Amino acids Carnivores Atmospheric nitrogen Loss to deep sediments Fish Plankton with nitrogen- fixing bacteria Nitrogen- fixing bacteria (plant roots) Nitrogen- fixing bacteria (soil) Denitrifying bacteria Death, excretion, feces Nitrifying bacteria Soil nitrates Excretion Decomposing bacteria Ammonifying bacteria
Phosphorus cycle Loss to deep sediment Rocks and minerals Soluble soil phosphate Plants and algae Plants Urine Land animals Precipitates Aquatic animals Animal tissue and feces Animal tissue and feces Decomposers (bacteria and fungi) Decomposers (bacteria and fungi) Phosphates in solution Loss in drainage