Population Studies

Population Studies Population- a group of individuals of a single species inhabiting a specific area Why study populations? Population too high or low = unstable ecosystem Low species diversity = unstable ecosystem Examples: Endangered Species = low population due to human impact Invasive Species = species introduced to a new ecosystem with no predators or competition allowing the population to increase rapidly

Examples of Invasive Species European Gypsy Moth Introduced from Europe in 1869 They were imported for silk production They defoliate sections of forest Brown Marmorated Stink Bug Native to Eastern Asia 1st found in Allentown, PA in 1998 Possibly arrived in shipping crates from Asia They feed on a variety of plants, including fruit trees, ornamental trees and shrubs, and some crops Currently found in the northeast, mid-Atlantic region and the Pacific northwest

What keeps populations from growing out of control? Limiting factors- A biotic or abiotic factor that a population needs as a resource. Can be either: Density Dependent or Density Independent Carrying capacity- the number of individuals an ecosystem can support. Amount of Food Disease Temperature Natural Disaster

Population Growth = When the birth rate exceeds the death rate, due to an abundance of resources.

J-Curve Population Graph J curve- exponential growth of a population because of no natural predators and an abundance of resources. (Usually followed by a population crash after exceeding its carrying capacity).

S-Curve Population Graph S curve- population increases to its carrying capacity & levels off due to predators or competition

Population Study Example What kind of relationship does the graph show? Which population seems to increase first before it drops? Is the hare and lynx relationship a density dependent or density independent limiting factor?