Bio171-F08-lec12 - Lecture 12: Monday September 29, 2008...

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Unformatted text preview: Lecture 12: Monday September 29, 2008 Biology 162 Todays Topic: Communities: Structure & Patterns Announcements 1st Exam Tonight 6-8 pm Format: answer all 30 MC questions and 4/5 SA questions Bring #2 pencil! Discussion this week: Ecology simulations Text Reading: Lecture 12: 2 nd ed: Ch. 53 (1232-41) 3 rd ed: Ch. 53 (1213-19) Lecture 13: 2 nd ed: Chapter 51 (1166-1190) 3 rd ed: Chapter 51 (1149-1170) Disturbance: Importance of Fire Succession: Primary & Secondary Clements & Gleason Models Area Effects & Latitudinal Gradients Bioaccumulation review Endocrine Disrupters & Human Sex Ratios 1st Exam: Monday Sep. 29, 6-8pm Exam 1 Locations: Aud B Angell Hall Sections: 009, 034, 013, 031, 044, 045, 012, 021, 041 GSIs: Katie, Hannah, Andres Aud D Angell Hall Sections: 005, 010, 014, 033, 039 GSIs: Laury, Dana 1210 Chemistry Sections: 011, 017, 029, 030, 037, 043 GSIs: Susan, Gyorgy MLB AUD 3 Sections: 008, 025, 028, 019, 035, 040, 015, 020, 038, 007, 016, 042 GSIs: Keith, Ed, Devon, Dieter NS AUD Sections: 023, 026, 032, 006, 022, 036, 018, 024, 027 GSIs: Sean, Senay, Peter Covers 1 st 10 lectures & 3 discussion topics Community Structure Through Time Research on species interactions usually focuses on just two species at a time, but biological communities contain many thousands of species. To understand how communities work, biologists explore how combinations of many species interact. One of the most interesting questions concerns how species diversity is maintained - how are dominant players restrained from forming monocultures? Disturbance and Change in Ecological Communities Disturbance is an event that removes some individuals or biomass from a community. The important feature of disturbance is that it alters some aspect of resource availability. Each community experiences a characteristic type, frequency, and severity of disturbance, known as a disturbance regime . Disturbances, such as fre, storms and Foods , play pivotal roles in structuring many biological communities. Ecologists use two approaches to determine the pattern of disturbance in a community: (1) inference of long-term patterns from data obtained in short-term analysis, and (2) reconstruction of the history of a particular site. Figure 53.20 shows the results of a study to determine the history of disturbance in a Fre-prone community from tree rings. This study established that fres are extremely Frequent in the community examined; but look at the 19th and 20th centuries. Why the plunge in Frequency? Patchiness and recovery following a largescale disturbance. The 1988 Yellowstone National Park fire destroyed large areas of forests dominated by lodgepole pines. A few years later - young lodgepole pines are growing back among the dead trees, reestablishing dominance....
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This note was uploaded on 01/30/2012 for the course BIO 171 taught by Professor Josephinekurdziel during the Fall '08 term at University of Michigan.

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Bio171-F08-lec12 - Lecture 12: Monday September 29, 2008...

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