Biological Communities in the World Around Us

1. Chapter 54 : Community Ecology Biological Communities in the World Around Us Big Idea #4 Interactions

2. What is a biological community? • A group of populations of different species living close enough to interact • Biome = community with a characteristic climate

3. Think outside the box… • What are the members of this community? • Are you a biological community?

4. Interactions within a community (54.1) • Competition • Intraspecific • Interspecific: • competitive exclusion • Predation • Including Herbivory • Symbiosis • Mutualism • Commensalism • Parasitism

5. 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?

6. 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.

7. Succession • Changes in community composition • Primary Succession • Secondary Succession

8. Does ecological succession occur when you take antibiotics? • How might this change impact the human body? (27.5)

9. 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?

10. 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

11. Shannon Diversity Index • The biodiversity of an area can be calculated using the equation: H = -(pAlnpA+ pBlnpB+ pClnpC….) • Higher values of H indicate greater biodiversity • We will practice using this equation in a separate activity • See 54.2 Example two forest communities.

12. 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.

13. 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

14. Experimental Design • Experimental Question: • How can humans impact the microbial community growing on cheese?

15. 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?

19. 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?