Chapter 6 Outline
I. Population Dynamics and Carrying Capacity
* Populations change in size, density, and age distribution; most members of populations live together in clumps or groups. * Three general patterns in a habitat: clumping, uniform distribution, and random dispersion. Most live in clumps or groups. * Availability of resources varies from place to place.
* Living in groups offers better protection from predators. * Some predator species live in packs to better have a chance to get a meal. * Temporary groups may form for mating and caring for young. * Uniform pattern distribution may occur where a resource is scarce. * Four variables influence population size: births, deaths, immigration, emigration. * Increase in population -birth and immigration.
* Decrease in population - death and emigration.
* Age structure of a pop. is usually described as the pre-reproductive stage, reproductive stage and post-reproductive stage. * large reproductive stage is likely to increase, while a population with a large post-reproductive stage is likely to decrease. * No population can grow indefinitely due to limited resources such as light, water, and nutrients and also due to competitors and/or predators. biotic potential is the populations capacity for growth.
* intrinsic rate of increase is the rate of population growth with unlimited resources. * Rapidly growing populations have four characteristics.
* reproduce early in life
* short periods between generations
* long reproductive lives
* multiple offspring each time they reproduce.
* Environmental resistance - factors that limit population growth. * Carrying capacity is determined by biotic potential and environmental resistance. This is the number of a species’ individuals that can be sustained indefinitely in a specific space. * As a population reaches its carrying...