Population Size

Population size: the total number of organisms in the population. Population density: the number of organisms per unit area. Population distribution: the location of individuals within a specific area. Features of Populations 1

What’s happening to the rabbits? Why? What will happen?

What’s happening to the rabbits? Why?

Natality (birth rate): the number of individuals born per unit time. Mortality (death rate): the number of individuals dying per unit time. Migration: the number moving into or out of the population. Population Dynamics Population size is influenced by births… …and deaths

Migration Migration is the movement of organisms into (immigration) and out of (emigration) a population. Populations lose individuals through deaths and emigration. Populations gain individuals through births and immigration. Migrating species may group together to form large mobile populations Wildebeest Canada geese

The number of individuals per unit area (for terrestrial organisms) or volume (for aquatic organisms) is termed the population density. At low population densities, individuals are spaced well apart. Examples: territorial, solitary mammalian species such as tigers and plant species in marginal environments. At high population densities, individuals are crowded together. Examples: colonial animals, such as rabbits, corals, and termites. Population Density High density populations Low density populations

Classify each of these factors as density-dependent or density- independent on population size 1)Rainfall - 2)Competition - 3)Predation - 4)Human destruction - 5)Parasites - 6)Temperature - 7)Disease - 8)Food availability -

Assignment: Create a concept map with interconnections, and action words about Population Size.