Population Dynamics

WARM UP 12/18/14 Draw the chart below and describe each relationship in the box on the right. Relationship Description Mutualism Commensalism Parasitism

Population Growth All organisms are members of populations Populations die and grow at steady rate based on the amount of resources available

Exponential Growth Populations experience exponential growth Initial increase in organisms is slow (small number of reproducing organisms) Population then sharply increases due to high amount of reproduction

Exponential Growth In exponential growth a populations rate of production grows Limitations: S-Curves Availability of food Disease Predators Lack of space A populations carrying capacity is the number of organisms than an environment can support Births exceed deaths until resources run out

Carrying Capacity  = The number of individuals in a population that an environment can support over a long period of time

Factors affecting populations Density Dependent Factor-Factors that have a stronger effect with increasing population Disease Predators Parasites Competition for food Density Independent Factor-Affects the population regardless of density: Volcanic Eruptions Storms Temperatures Drought

Human Population Demography-Study of human population size, density and distribution United States Census is taken every 10 years

Human Population Human growth is different from other organisms because humans have the ability to change their environment Found cures for diseases Found methods to produce food Been able to provide clean water

Age Structure Age Structure-Proportions of the population that are in different age groups Age structure graph shows how many males and females there are in each age group

Write these definitions: Exponential Growth: initial increase is slow, then increase sharply Limiting Factor: A factor present in an environment that controls growth Carrying Capacity: the number of organisms that an environment can hold over a long time Density Dependent Factor-Factors that have a stronger effect with increasing population Density Independent Factor-Affects the population regardless of density