mcdb20lec14su09

Mcdb20lec14su09 - Lecture 14 recap ecosystem function Biodiversity Human influences Conservation strategies Human solutions Energy flows through an

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Lecture 14: recap: ecosystem function Biodiversity Human influences Conservation strategies Human solutions Energy flows through an ecosystem to heat Nutrients cycle within biosphere and physical environment 3 Energy Pyramid the 10% rule Biodiversity 4 Consequence of macroevolution Biodiversity benefits humans. ! Biodiversity provides significant benefits to humans in numerous utilitarian ways, such as the production of medicines and other products and processes. Consider: ! Methylsalacylic acid (aspirin). Willow bark (anti-inflammatory) ! Colchicine: Crocus alkaloid (Gout treatment) ! Vinblastine and Vincristine: Vinca alkaloids (important anticancer drugs) ! Ancrod: Pit Viper venom anti coagulant (potential stroke treatment) ! Epibatidine: Frog skin alkaloid (analgesic 200X more potent than morphine) Biodiversity benefits humans.
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What is the biodiversity in a particular patch of land? ! Defining biodiversity is difficult because it can be considered at multiple levels, from entire ecosystems to species to genes and alleles. ! In practice, it is most often defined as the number of distinct species in a habitat ! GOAL: Preserve Biodiversity (started in 1978 at a UCSD conference) Conservation Biology Where is the most biodiversity? ! Biodiversity is not evenly distributed. ! There is a strong latitudinal gradient of biodiversity from the tropics (highest biodiversity) to the poles for nearly all groups of plants and animals, both marine and terrestrial. Island biogeography helps us understand the maintenance and loss of biodiversity.
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Island Recolonization 1) The closer islands were recolonized more quickly than the distant islands. 2) On all of the islands, the number of insect species after fumigation returned to about the same number of insect species prior to fumigation. 3) The composition of insects on each island changed over the course of the study, even on the two control islands. ! Both the size of the habitat and its distance from a pool of new species influence the equilibrium number of species present. ! Ideas gained from island biogeography have important implications for the development of nature preserves. There are multiple causes of extinction. ! Background extinctions tend to be a consequence of one or more features of the species’ biology.
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! Extinctions can occur for fundamentally different reasons. ! Mass extinctions are more the result of bad luck than particulars of a species’ biology. We are in the midst of the 6th Mass Extinction ! Current rates of extinction in every well- studied group of plants and animals support the hypothesis that a mass extinction is underway. ! Seems to be the result of the activity of one keystone species: humans. Scientists have recorded more than 200,000
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This note was uploaded on 09/14/2009 for the course MCDB 20 taught by Professor Cooper during the Summer '08 term at UCSB.

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Mcdb20lec14su09 - Lecture 14 recap ecosystem function Biodiversity Human influences Conservation strategies Human solutions Energy flows through an

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