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OUR Ecological Footprint - 13 1. Recycle; pay tax for it. 2. Live near work; ride bike; minimize car use. 3. Buy energy-efficient furnace. 4. Programmable thermostat: winter/summer 5. Turn off lights when leave room; unplug appliance 6. Eat lower on food chain. 7. Buy foods locally; avoid transport/energy costs. 8. Use energy-efficient light bulbs. 9. Reduce paper/plastic (and ALL) consumption. 10. Reduce garbage + consumption of paper/plastic. 11. Be a selective fish eater. 12. Lengthen cycle of resource use; wear it out! 13. Change lifestyle of greater consumption towards a lifestyle based on voluntary simplicity…
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ENRICH YOUR RESUME… THIS THURSDAY 4-5 217 NOYES LAB IB students describe out-of-class opportunities Obtain info on how to find out about these, when/how to apply
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Last lab… 3rd Annual Ecology Symposium Lab/TA evaluation
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Chapter 25: Extinction + Conservation
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Chapter 23 Biodiversity Chapter 24 History and Biogeography
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Objectives Species diversity: different geographical scales Factors at local vs. regional scales Equilibrium theories of species diversity Island Biogeography Theory Regional-scale species diversity Patterns and causes Effect on local diversity Latitudinal-scale species diversity Continental/global scale and role of history Equilibrium in s.d. over time? Continental drift: separation, joining, and biotic exchange Role of climatic change
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Multiple scales of species diversity Local Regional Latitudinal Continental Global Ecological vs. Evolutionary Time… Role of history
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Many factors influence local and regional species diversity
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Multiple scales of species diversity Local Regional Latitudinal Continental Global
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Equilibrium theories: diversity reflects a balance between processes that add vs. remove species. ***What processes add species? speciation immigration What processes subtract species? extinction emigration Differences in diversity between communities reflect differences in relative rates of these processes.
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Equilibrium theory in continental communities: balance between speciation and extinction on regional scale
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Equilibrium theory of island biogeography: # species = balance of immigration on a regional scale vs. extinction on local scale.
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Islands closer to the mainland support more species because of higher immigration rates.
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Larger islands support more species because of lower extinction rates.
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*** What is the pattern? What explains it?
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***Why do smaller islands have fewer species?
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*** Do experimental results support ETIB?
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Applications of Island Biogeography Theory (IBT) to: Terrestrial systems e.g. mountain tops as islands fragmented remnants as islands Design of nature reserves
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Regional-scale patterns of diversity reflect: Habitat heterogeneity Suitability of physical conditions Isolation from centers of diversity
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***What are three patterns in species diversity? What factor accounts for each pattern?
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Comparing diversities of communities in similar habitats in different regions can reveal regional effects.
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Saturation of local communities: test how local and regional diversity relate.
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Variation in local species diversity depends on regional diversity. ***Are local communities saturated?
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***What are major changes among regions from Tertiary to present? What accounts for them?
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Mangrove vegetation is less diverse in the New World than the Old World tropics.
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Mangrove vegetation occupies a greater ecological range where it is most diverse.
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Multiple scales of species diversity Local Regional Latitudinal Continenta Global
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***What is latitudinal gradient in woody species diversity? What explains it?
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Hypotheses to explain latitudinal gradient in species diversity Time Energy Productivity Heterogeneity in space and time (Vegetation and food complexity) Predation Competition/niches Disturbance Equilibrium models
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Time hypothesis Tropics are older (and less disturbed??) --->more time to accumulate species. What happened to climate in the tropics during glaciation? What happened to species in the tropics during glaciation? Increased speciation from fragmentation? Did extinction increase?
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Many factors influence regional and local species diversity
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Multiple scales of species diversity Local Regional Latitudinal Continental Global
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Equilibrium theories: diversity reflects a balance between processes that add vs. remove species. Add species: speciation immigration Subtract species: extinction emigration Has regional species diversity been constant (in equilibrium) over long periods of time?
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How do history + biogeography influence local communities and sp. diversity?
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History of life is gauged by geologic time scale.
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***Has diversity been constant?
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Catastrophes --> major changes in direction of evolution Asteroid impact--> extinctions
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Continental drift --> positions of continents change over geologic time.
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Continental drift changed routes of dispersal via separation + joining.
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Exchanges of biotas after joining of continents: e.g. The Panama land bridge
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Lineages of ratite birds separated by fragmentation of Gondwana.
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Organisms are not distributed uniformly over earth.
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Phylogenetic effects traits shared by lineage irrespective of environment e.g. marsupial model of reproduction due to lineage of evolution not due to environment in Australia
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Wallace: Major zoogeographic regions reflect long-term evolutionary isolation.
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In contrast, similar environments among regions leads to convergent evolution.
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Similar solutions to common problems…
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How climatic history determines species distributions
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Climate change shifts species diversity.
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Local diversity as f(continental diversity).
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Objectives Species diversity: different geographical scales Factors at local vs. regional scales Equilibrium theories of species diversity Island Biogeography Theory Regional-scale species diversity Patterns and causes Effect on local diversity Latitudinal-scale species diversity Continental/global scale and role of history Equilibrium in s.d. over time? Continental drift: separation, joining, and biotic exchange Role of climatic change
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Vocabulary
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