Lecture 6: Biodiversity

January 21, 2010

9:00	1. Kolbert chap 4	Trevor Sheffels will present this lecture. John Rueter is at the NCSE meeting on the Green Economy until Friday and then the CEDD meeting on Saturday.
	2. cycles
	3. reasons to study cycles
	4. water
	5. carbon
	6. phosphorus
	7. nitrogen
	8. inter-related cycles

 

1. Different definitions of biodiversity

scale and ecological level of study

• functional diversity
• ecological diversity
• genetic diversity
• species diversity

valuable natural capital that has developed as a resource over billions of years

2. Adaptation, natural selection and evolution

many processes work together to create genetic, physiological diversity

more than just "survival of the fittest"

• mechanisms to generateof diversity at the individual level
• natural selection that allow higher reproduction
• barriers to overproduction that keep one type from wiping out all the accumulated diversity in a population

speciation through geographic and reproductive isolation

types of extinctions

• local (one population)
• global (everywhere in the world - loss of the species)

3. Diversity is important

immediate functioning of an ecosystem

• need the range of functional groups to process nutrients and energy
  • trophic levels
  • different functions within trophic levels (trees, shrubs, grass)
• organisms interact with each other
  • more diversity leads to even more diversity
  • more opportunities for unique species to species interactions

resilience of ecosystems often depends on a range of species types

• definition of "resilience" - ability of an ecosystem to return to a general pattern of functioning after some stress
  • loss of resilience is when an ecosystem flips to another state (pattern of functioning)
• many species can spread the stress
• more diverse grasslands handle drought stress with less of a loss of productivity and quicker recovery

response to large shifts such as global climate change

 

 

4. Niche

role of organism

narrow vs. broad (specialist vs. generalist) - examples

 

 

5. Impact of non-natives

different categories of introduced species

• ? introduced
• naturalized
• invasive

examples:

• english ivy
• nutria

 

 

6. Keystone and Foundation species

keystone species -

• definition
• example

foundation species -

• definition
• example

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