BIOLOGY Chapter 16: Changes In Ecosystems


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  • Pollutants have water vapour adhered to it = man made clouds. Clouds hold HEAT in. So no clouds = colder. After 9/11, shut down jet traffic in USA for three days. Scientists able to observe during that 3 day period, there was about 1*C change over the 3 days. This change over a long period = climate change… can impact ecosystems.
  • intergovernmental panel on climate change Different countries put their data together Study how changes in temperature affect our planet Raise in temperature affect arctic ecosystems more than ecosystems closer to equator. Impact on the species that have evolved to live in cold temperatures.
  • 1ºC change over next 100 years All coral becomes bleached. Coral made up of two things = a coral (essentially an animal) + algae (plant, lives mutualistic with them) Coral will extrude (force out) the algae, so can’t use photosynthetic process of algae = bleached. Increase temperature = warmer.. Affect 10% of world’s ecosystems. - Affect arctic ecosystems more. - Species can’t evolve quickly enough to adapt to the change in climate = impacted by that.
  • 2ºC change over next 100 years
  • 3ºC change over next 100 years 1/2 of nature reserves unable to meet conservation objectives Manmade change… Environment impacted by humans.
  • Primary change Due to human intervention or natural agents
  • PRIMARY CHANGE Manmade change: Introduction of exotic/alien-species Noxious species, e.g. rabbits, cane toads. Page 510. Manmade change: Overharvesting of a biological resource (e.g. fishing too much, hunting of animals) page 517. Natural change agents: Bushfires. Page 528. Obligate seeder plants (seeds survive and germinate after fires) Vegetative reproducer plants (regrow through means of (epicormic)buds located under bark or in underground stems/rhizomes) Fire is important agent of change in some Australian ecosystems (e.g. page 531 “fire for parrots”)
  • Primary succession: ecosystem must rebuild after being completely destroyed (including the soil) Main feature of primary ecological succession = soil formation. - Rock exposed of receding glacier New land formed by volcanic explosions Mosses and lichens (spore bearing plants) = pioneer organisms … Lichens secret toxins into rocks = break down into soil Wearing down of rocks by weather/water = form soil When mosses and lichens die = biomass degrades into soil Secondary succession: ecosystem must rebuild with the soil still intact. e.g. small bushfire… doesn’t have to go through process of soil formation… No pioneer organisms because there are already organisms in and around soil. Process of succession stops when a stable community becomes established. Stable community = climax community.
  • Frequency of change: Changes in ecosystems may occur regularly, sporadically, or due to one-off events. (1) Identify a change agent that acts on an ecosystem as follows: Regularly, sporadically (irregularly), or as a one-of event. (2) Give an example of change in an ecosystem that is due to: a. human intervention… b. a naturally-occurring agent of change. - Invasive exotic species cause negative effects in ecosystems. - Over-harvesting of a biological resources can cause populations to crash. - Fire is an important agent of change in some Australian ecosystems.
  • BIOLOGY Chapter 16: Changes In Ecosystems

    1. 1. Changes in ecosystems Chapter 16 (Page 500)
    2. 2. Harm to Coral Reef 0.5ºC over next 100 years and Arctic Ecosystems
    3. 3. All coral reefs bleached 1ºC over next 100 years 10% of global ecosystems transformed
    4. 4. Mass mortality in coral reefs 2ºC over next 100 years 1/6 of global ecosystems transformed 1/4 species committed to extinction
    5. 5. 1/2 of nature reserves unable to meet conservation objectives 3ºC over next 100 years 1/5 of global ecosystems transformed 1/3 species committed to extinction
    6. 6. Could the damage be reversed?
    7. 7. Primary changes in ecosystems may produce a cascade of secondary changes that may not become apparent immediately. What are the primary and secondary changes in the: Panda example? Temperature change example?
    8. 8. Frequency of change  Regular and predictable events (e.g. tides and seasons)  Sporadic (irregular) events (e.g. floods)  One-off events, planned or unpredictable (e.g. oil spill)  Examples of changes?
    9. 9. Activity! (20 minutes)  Split into 3 teams of 5-6 people. Each team will be given a scenario with primary change.  TASK: Create a strategic plan to restore the ecosystem back to it's original state. In the plan you have to highlight :  What is the primary change and how has it impacted the ecosystem and the organisms that live there?  Identify the secondary changes that may occur.  Can the damage be reversed? If so, how can the balance of the ecosystem be restored?
    10. 10. UN Meeting on Climate Change  Primary change  Secondary changes  Can the ecosystem be restored? How?
    11. 11. Succession in ecosystems: The natural replacement over time of one community by another community with different dominant species. Primary succession Secondary succession
    12. 12. Key ideas  Primary changes and secondary changes  Frequency of change?  Can damage of an ecosystem be reversed/restored?  Primary succession vs. Secondary succession Invasive species Over-harvesting Fire = important
    13. 13. Invasive species + over-harvesting  Goats on trees found in Morocco.  Like to eat the fruit of the argan tree, which is similar to an olive  The argan tree slowly disappearing due to over-harvesting for the tree's wood and overgrazing by goats.
    14. 14. Interesting websites  The world’s 10 worst invasive species:  Invasive species specialist group:  Invasive species database: