Post on 23-Jan-2016
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Biological Communities in the World Around Us
Big Idea #4Interactions
Chapter 54 : Community Ecology
What is a biological community?• A group of
populations of different species living close enough to interact
• Biome = community with a characteristic climate
Think outside the box…
• What are the members of this community?• Are you a biological community?
Interactions within a community (54.1)
• Competition– Intraspecific– Interspecific:
• competitive exclusion
• Predation– Including Herbivory
• Symbiosis– Mutualism– Commensalism– Parasitism
Competitive Exclusion Principle defines an organisms niche
• How might this play out in the human body? What conditions in the human body cause a different member of the community to be successful?
Also important…
• Dominant Species: usually most abundant…what if they change?
• Keystone Species: not usually abundant…why might you start seeing them?
• Ecosystem engineers: foundation species…drives change in other species.
Succession
• Changes in community composition– Primary Succession– Secondary Succession
Does ecological succession occur when you take antibiotics?
• How might this change impact the human body? (27.5)
Nitrogen cycling in a biological community• What types of organisms play a critical role? (27.5)• How might changing the members of the community
affect nitrogen cycling? • What events might cause succession/change?
How can succession be measured?
• Species biodiversity is used to characterize a community---so-called “climax communities” have stable, distinctive organisms
• Higher biodiversity = greater succession• The impact of events on a community may be
evaluated by studying changes in biodiversity
Shannon Diversity Index
• The biodiversity of an area can be calculated using the equation: H = -(pAln pA + pBln pB+ pCln pC….)
• Higher values of H indicate greater biodiversity
• We will practice using this equation in a separate activity
• See 54.2 Example two forest communities.
What’s this all got to do with cheese?
• Cheese is the scaffold for a microbial community – a microbiome.
• The process of making cheese involves an understanding of biology.
New England Cheese Economy
• From these Chronicle clips, appreciate an understanding of why biologists (yes…ones at that big University in Cambridge, MA) might be interested in the cheese making process.
• Part 1:http://www.wcvb.com/chronicle/Vermont-s-Cheese-Trail-Part-1/-/12523032/13392120/-/ute169/-/index.html
• Part 2:http://wedgeintheround.com/2012/11/11/vermonts-cheese-trail-part-2-chronicle-wcvb-home/
• Part 3:http://www.wcvb.com/chronicle/Vermont-s-Cheese-Trail-Part-3/-/12523032/13392188/-/13v2y1t/-/index.html
Experimental Design
• Experimental Question:– How can humans impact the microbial community
growing on cheese?
What background do you need to know?
• How is cheese made?• What types of conditions is cheese cultured
under?• What types of bacteria usually grow on
cheese?
Designing an experiment
• What is an independent variable?– What could be an independent variable in this
lab…what do you need to know?!?!• What is a dependent variable?– What qualitative results might you observe?– Is there a quantitative dependent variable that
would be appropriate to this lab?