APES Unit 2.5 Natural Disruptions to the Ecosystem

What conclusion have scientists come to when talking about the “sixth

mass extinction?”

Humans create environmental changes by pushing species outside their ecological tolerance

• Sixth Global Mass Extinction: Extinction of 2 species a year

• Climate Change: Changes in the amount of solar radiation and changes in the

  atmosphere, like increases in CO2, have contributed.

List and describe the 3 main periodic time frames.

• Periodic: events that occur regularly, like rains and flooding and deposition, and day or night cycles.

• Episodic: events that occur regularly but less frequently, like cycles of high and low rain and tornadoes.

• Random: events that have no pattern, like tornadoes and volcanic eruptions.

Resistance

measures how much a disaster can affect the flows of energy and matter

• High resistance: disruption influences populations but has no effect on overall energy flow

Resilience

rate at which an ecosystem returns to its original state after a disruption.

• Ecosystem resilience: depends on biogeochemical and hydrological

cycles

Migration

seasonal movement of animals from one habitat to another

• response to seasonal changes in food or mating possibilities.

• Short term migration: temporary movement

  • ex. grazing animals moving to find food.

• Long term migration: permanent movement

  • ex. birds migrating during the winter.