Lecture 23. Function and value of Biodiversity-posted

Lecture 23. Function and value of Biodiversity-posted -...

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Function and value of Biodiversity Biodiversity is under threat as we are in the midst of a 6 th mass extinction.
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(Thomas et al 2004 Science) Actual data on local species loss (or gain) in the UK Introduction of new species
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Biodiversity… what’s it good for anyway? 1. Humans depend on species for food, clothing and medicine (50% of all prescribed drugs contain or are based on plant, animal or microbial products) 1. Aesthetic pleasure and the dependence of tourism revenues on biodiversity
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1. Diversity affects both the structures and functioning of local communities Ecological extinction Ecological extinction - occurs when a species has become so rare that has no effect on an ecosystem (so rare that it Can no longer pick up the Slack. Diverse commun more stable
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If the resource axis is finite, adding species will increase the competition coefficient between pairs of species, decreasing the likelihood of coexistence Resource Performance Resource Performance Few species = Many “empty niches”, susceptible to invasion. Many species = Few “empty niches” resistant to invasion. Corollary : as you add species, the probability of establishment of new species should decrease: _biotic resistance-ability of diverse communities to resist invasion_ Invasion difficult Invasion easier
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Diversity reduces invasion More species reduce the number of species that can invade an ecosystem
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Introduced species are:
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This note was uploaded on 11/29/2010 for the course BIOLOGY 1211 taught by Professor Patricelli during the Spring '10 term at UC Davis.

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Lecture 23. Function and value of Biodiversity-posted -...

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