Population Growth

1. Population Growth • Exponential Growth • J-shaped curve • Lag phase is the initial growth phase • Exponential Growth phase • When the birth rate outnumbers the death rate • The environment is fulfilling their biotic potential,maximum possible growth under ideal circumstances(i.e. unlimited resources, plenty of room, etc.) • Logistic Growth • S-shaped curve • The growth is slow at first, steepens, then levels off due to environmental resistance • Carrying capacity: maximum number of species anenvironment can support • Deceleration occurs because there is environmental resistance(i.e. finite amount of resources)

2. Regulation of Population Size • Density-independent factors: • Abiotic factors: weather and natural disasters • Density-dependent factors: • Biotic factors: Competition, predation pathogens, and parasites Life History Patterns • R-selection • lots of offspring with little support from the parents (i.e. of r-strategists are plantsand amphibians) • K-selection • little offspring with a lot of support from the parents (i.e. of k-strategists are most mammals) Human Impact Less developed countries account for most of the exponential population growth, but more-developed countriesgreatly impact the environment withgreater carbon emissions.