mitch lange jack connor kelly goehring http:// pg
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Mitch LangeJack Connor
Kelly Goehring
Population Ecologyh
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What is it exactly?
Studying populations in relation to the environment… Environmental influences, on population density, distribution, age
structure, and population size
With more of these guys…
There will be less of these guys
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Population DensityPopulation size can be determined in a number of ways:
Like number of nests, burrows, tracks, or poopAdditions to population occur from :
http://www.scotlandincolour.com/finch/finches-flying01ll.jpg
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Population Size
ImmigrationBirths
Leaving So Soon?
Animals leave because of:
Deaths & Emigration: Movement of animals out of a population
http://www.ect.coop/wp-content/uploads/2010/08/Osprey-Leaving-Nest.jpg
http://laudyms.files.wordpress.com/2010/03/hawk_eating_prey.jpg
Dispersion 3 types:
http://mycozynook.com/36_02aClumpedDispersion-L.jpg
http://bio1903.nicerweb.com/Locked/media/ch53/53_04cRandomDispersion-L.jpg
http://bio1903.nicerweb.com/Locked/media/ch53/53_04bUniformDispersion-L.jpg
• Clumped: Most common, with individuals in separate patches• Uniform: Evenly spaced, with patterns resulting from interactions• Random: Unpredictable Spacing
Demography
Vital Statistics of populations and their change over time Particularly looking at birth rate and death rates Life Table
Age that a person/animal is expected to live to Cohort= group of individuals of same age. Used to follow the fate from birth to
death
Survivorship Curve• Plot to see which data points in a
cohort are still alive
http://bealbio.wikispaces.com/file/view/survivorship.gif/104532503/survivorship.gif
Life History Some species reproduce in a one shot chance called semelparity
If offspring survival rate is low, this is favored Others reproduce in the annual cycle called iteroparity
More favorable when there is dependable environment and might be competition for resources
There are many trade-offs between reproduction and survival: High mortality rates in offspring often exhibit large number of small offspring High predation rates also factor into large numbers of offspring
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Time For Math
Per Capita Rate of Increase is the amount a population goes up over time Deaths>Births is declining population Births>Deaths is growing population Births=Deaths is zero population growth
Intrinsic rate of increase or rmax is when the per capita rate of increase is at its maximum
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Logistic Growth Model
With more population density, each individual has access to fewer resources
The carrying capacity is the max population an environment can support In this model, the per capita rate of increase declines as carrying capacity is
reached The graph of most real populations is like an S shape When the population increases to it there is a lag in time where the population
can resettle
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Things Are Complex
• Density Dependency• Death rate rises as population density rises• Also a birth rate falling with rising density
• Density Independency • Birth rate or death rate does NOT change with population density
Density Dependent
Competition for Resources More population more competition
Territoriality Territory space is what the animals compete for i.e: nesting sites
Health Transmission rate of a disease can wipe out a population
Predation More food captured means lowered population
Toxic Wastes Intrinsic Factors
Physiological effects of things like over-reproduction
http://www.grguy.net/Q2_30Y3399-Cheetah-marking-300.jpg
http://recyclingewaste.files.wordpress.com/2011/09/toxic-waste.jpg
Things Are Still Complex
Population Dynamics Metapopulations
Population Cycles = predictable intervals
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Humans
People Population Growth
1962-no longer y^x Demographic Transition Developed countries: reproduction rates about = replacement level Population growth in Developing countries
http://www.mongabay.com/images/pop.gif
Age Structure
Relative number of individuals at each age
Global Carrying Capacity-Humans
Some say a billion, some say a trillion Ecological Footprint( EF)
Produce all resources, absorb all wastes Ecological Capacity( EC)
Actual resource base of their country U.S. EF= 8.4 ha, EC= 6.2 ha World EF= 1.7 ha
http://sunhomedesign.files.wordpress.com/2009/04/cc-graphic1.gif
Limiting Factors
Space Nonrenewable Resources Renewable Resources Earth’s Capacity to Absorb Wastes