ENVS 2330 Quiz: MIDTERM 2
20 Dec 2018
School
Department
Course
Professor
MIDTERM 2
*NOTE: These notes start Lecture 10 Oct 16th (after midterm 1). However, exam is CUMMULATIVE
KEY ARTICLES (review these with the ppt slides to study)
• https://www.youtube.com/watch?v=767slG‐Nlhk - Video on overfishing
• http://science.sciencemag.org/content/314/5800/787 - Worm article about
loss of biodiversity in oceans
• https://www.youtube.com/watch?v=IGslY‐JOeJ0 - Ray Hilborn combating
above mentioned article
• http://science.sciencemag.org/content/325/5940/578 - Hilborn and Worm
working together
• Maybe look up Don et al. (2010) from Nov 1 lec? (pg 19)
• https://www.ted.com/talks/paul_hessburg_why_wildfires_have_gotten_wors
e_and_what_we_can_do_about_it?language=en – Wildfires!!
• https://courselink.uoguelph.ca/d2l/le/533043/discussions/posts/6142540/Vie
wAttachment?fileId=4614392 – Oil palm
• https://www.thestar.com/news/insight/2015/09/27/is-david-keiths-climate-
solution-genius-or-madness.html - Sulfur to counter climate change
• https://www.ted.com/talks/david_keith_s_surprising_ideas_on_climate_chan
ge/up-next?nolanguage= - Same as above, Keith’s tedtalk on climate change
ECOSYSTEM COMPLEXITY
• Ecosystems are complex adaptive systems
- Complex adaptive system – system where perfect understanding of
individual parts does not automatically convey perfect understanding of
whole system
• Bottom up self organization leads to stability
- Resistance – how far does a system move when you kick it?
- Resilience – how quickly does a system return to pre-kick conditions?
~ Capacity of a system to absorb disturbance and undergo change so it
can retain the same function, structure, identity, and feedbacks
- Variability – how much does a system vary over time with no of a kick?
- ALL 3 are required when it comes to stability
• Ecosystem stability – the ability of an ecosystem to maintain its structure
and function over long periods of time despite disturbances
- Most natural ecosystems experience disturbances regularly
- Loss of stability could damage ecosystem structure and function
BALL AND CUP
• Ball = current state of system, cup = current stability domain
• Stability – speed at which ball returns to homeostasis
• Resilience – amount of energy system can absorb without leaving cup for
alternative stability domain
• Resistance – amount of energy it takes to alter system (i.e. is the ball a beach
ball or bowling ball)
• Range of Natural Variability (RONV) – range of possible locations of the
ball within the cup
• Goal: Stay in the cup, cup remains as wide and deep as possible
FEEDBACKS
• Negative: Stabilizes ecosystem, Positive: Destabilizes ecosystem
• Changing enviro conditions can cause decline of local biodiversity
- Alters resistance or resilience and ecosystem could loose stability
• Response to disturbance depends on resistance and resilience AND:
- Robustness – amount of disturbance system can absorb without flipping
to alternative state
- Response – magnitude of change
- Recovery – extent of return to original state
Document Summary
*note: these notes start lecture 10 oct 16th (after midterm 1). Ecosystem complexity: ecosystems are complex adaptive systems. Complex adaptive system system where perfect understanding of individual parts does not automatically convey perfect understanding of whole system: bottom up self organization leads to stability. ~ capacity of a system to absorb disturbance and undergo change so it can retain the same function, structure, identity, and feedbacks. All 3 are required when it comes to stability: ecosystem stability the ability of an ecosystem to maintain its structure and function over long periods of time despite disturbances. Loss of stability could damage ecosystem structure and function. Feedbacks: negative: stabilizes ecosystem, positive: destabilizes ecosystem, changing enviro conditions can cause decline of local biodiversity. Alters resistance or resilience and ecosystem could loose stability: response to disturbance depends on resistance and resilience and: Robustness amount of disturbance system can absorb without flipping to alternative state. Recovery extent of return to original state.
