1 introduction ecologists usually define a population as… – characterized by the number of...
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Introduction• Ecologists usually define a population as…
– Characterized by the number of individuals and their density.• Additional characteristics of a population include…
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Distribution Limits• _____________________ limits geographic
distribution of a species.– Organisms can only compensate so much for
environmental variation.
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Niches• _______: Summarizes environmental factors
that influence growth, survival, and reproduction of a species.– Grinnell’s definition focused on the effects of the
physical environment– Elton’s definition included biotic and abiotic
factors
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Niches• Hutchinson defined niche as:– • n equates the number of environmental factors
important to survival and reproduction of a species.
–___________________- hypervolume
–___________________ includes interactions such as competition that may restrict environments where a species may live.
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Kangaroo Distributions and ClimateBIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Tiger Beetle of Cold Climates
• Tiger Beetle (Cicindela longilabris) lives at higher latitudes and elevations than most other species in NA.– Schultz et. al. found metabolic rates of C.
longilabris are higher and preferred temperatures ____________ than most other species.• Supports generalization that the physical environment
limits species distributions.
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Tiger Beetle of Cold ClimatesBIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Distributions of Plants Along a Moisture-Temperature Gradient
• Encelia species distributions correspond to variations in temperature and precipitation.
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Distributions of Barnacles Along an Intertidal Gradient
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Distributions of Barnacles Along an Intertidal Exposure Gradient
• Organisms living in an intertidal zone have evolved to different degrees of resistance to…
– Barnacles show …
• Connell found Chthamalus stellatus restricted to upper levels while Balanus balanoides is limited to middle and lower levels.
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Distributions of Barnacles Along an Intertidal Gradient
• Balanus appears to be more vulnerable to _____________, excluding it from the upper intertidal zone.
• Chthamalus adults appear to be excluded from lower areas by _____________ with Balanus.
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Distribution of Individuals on Small Scales
• _____________: Equal chance of being anywhere.–
• _____________: Uniformly spaced.– –
• _____________: Unequal chance of being anywhere.– –
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Distribution of Individuals on Small Scales
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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What pattern? Why?
http://soundwaves.usgs.gov/2004/11/NestingColonyLG.jpg
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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What pattern? Why?
http://i.telegraph.co.uk/telegraph/multimedia/archive/01216/gnu_1216499c.jpg
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Species of aggressive stingless bees that forage over clumped resources… how would you predict they be distributed? How about passive species foraging on regularly spread resources?
http://farm3.static.flickr.com/2359/2459405670_f8082401c0.jpg
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Distribution of Tropical Bee Colonies
– As predicted, four species with regular distributions were highly aggressive.• Fifth was non-aggressive and ___________ distributed.
• Prospective nest sites marked with ____________.
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Distributions of Desert Shrubs
• Traditional theory suggests desert shrubs are regularly spaced due to competition but….
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Organism Size and Population Density
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
Density decreases as body size…
How does aquatic invertebrate density cmopare to that of other animals of comparable size?
How does mammal density compare to bird density?
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Plant Size and Population Density
• Plant population density ___________ with ____________ plant size.– Underlying details are very different.•
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Commonness and Rarity• Rabinowitz devised commonness classification
based on (3) factors:• • •
• Populations that are least threatened by extinction, have extensive geographic ranges, broad habitat tolerances, and some large local populations. – All seven other combinations create some kind of
rarity.
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Rarity
• Rarity I–
• Peregrine Falcon
• Rarity II–
• Passenger Pigeon
http://falconrytoday.net/news/wp-content/uploads/2009/08/Peregrine-Falcon0014.jpg
http://www.saroffillustration.com/portfolio/page/ns4_pigeon.jpg
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance
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Rarity
• Rarity III–
• California Condor
http://www.dfg.ca.gov/wildlife/hunting/condor/images/condor119.jpg
BIOL 3240 Plant and Animal Ecology – Distribution & Abundance