APES APEX 3.2.6 Read (Withgott 7th) Change in Ecosystems

• small-scale disturbance


  A tree falling creates a gap in the tree canopy, altering light and other conditions for plants and animals in the gap.
• large-scale disturbances


  Hurricanes, tornadoes, volcanic eruptions, landslides, floods, and climate change.
• normal disturbances


  Disturbances that regularly occur.
• resistant community


  A community that remains stable and does not change in the face of a disturbance.
• resilient community


  A community that changes but then changes back to its original state.
• Mount St. Helens eruption


  A fairly recent large-scale community disturbance in 1980 that altered ecologists' view of how communities respond to disturbance.
• phase shift


  A change caused by passing a crucial climatic threshold, the loss of a keystone species, or the invasion of a nonnative species.
• coral community phase shift


  Overharvest of fish or turtles that eat algae has resulted in the overgrowth of algae in some coral reefs — a phase shift that may be permanent.
• weather


  The conditions at a particular location over hours or days.
• climate


  The average conditions over a larger area over a period of years.
• global warming


  The rise in the average surface temperature of Earth.
• global climate change


  The array of changes in aspects of Earth's climate, including precipitation, temperature, storm intensity, and storm frequency.
• Milankovitch cycles


  Periodic episodes of glaciation during which ice sheets expand outward from the poles due to a decrease in surface temperature.
• solar output and warming


  While changes in solar output can change temperatures on Earth, variations in solar output through recent centuries have been too slight to cause Earth's recent warming.
• ocean warming and CO2 absorption


  The oceans absorb CO2, removing it from the atmosphere. But warmer water absorbs less CO2, leaving it in the atmosphere, which will further increase warming of the atmosphere.
• El Niño and La Niña


  Involve shifts in sea surface temperature, ocean circulation, and atmospheric pressure in the Pacific Ocean over periods of years, leading to droughts, rainstorms, floods, and other extreme weather.
• global warming effects on timing


  Vegetation leaves out earlier in spring; insects hatch earlier; birds and mammals breed earlier.
• global warming effects on ranges


  Plants and animals have shifted their ranges toward the poles to escape rising temperatures in their former ranges.
• global warming effects on elevations


  Many species have moved to higher elevations as their former homes have become too warm.
• benefit of climate change


  Plants remove CO2 from the air. If they reduce CO2, a greenhouse gas, to a great enough degree, global warming might decrease as well.
• disturbance


  In a community, an event that changes environmental conditions rapidly and drastically.
• resistance


  The quality of resisting change and remaining stable despite disturbance.
• resilience


  The quality of changing temporarily in response to disturbance but later returning to the original state.
• regime shift


  A change in the fundamental character of a community in response to a disturbance; also called a phase shift.
• novel community


  A community that is composed of new mixtures of plants and animals as a result of human disturbance.