Effects of plant diversity on nutrient cycling in a California serpentine grassland

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Population Ecology 4 - Life Tables   (Chap.
10) A. Patterns of survival and reproduction B.
Age distributions C. Calculating rates of
population change a. non-overlapping
generations b. overlapping generations  
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A. Patterns of survival and reproduction

• What do we need to know about popn to figure out
  b and d so we can figure out r?
• Are birth and death rates similar for all
  individuals in a population?
• How do b and d vary with age?

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1. Survivorship curves show how likelihood of
death varies with age
10.16
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10.14
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(Annual)
Humans too!
10.15
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10.17
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10.18
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10.14
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2. Fecundity curves timing of reproductionDiffer
ent fecundity curves for Chinook and Coho salmon
Hill et al. (2003) J. An. Ecol. 72 736
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Fecundity for humans and oak trees
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3. Relationship to life history
traits Reproductive allocation vs.
growth/survival - limited resources -
reproduction is energetically expensive -
different reproductive strategies a. frequent
disturbances b. stable environments
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a. Reproduction vs. growth tradeoffs examples
Fruit flies
Fruit flies
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b. r- vs K-selection
r-selection K-selection

1. Disturbance Common, irregular Rarer, more
   regular
2. Mortality Variable, unpredictable Constant,
   predictable
3. Competition Low or variable High, constant
4. Pop. size Variable, below K Rel. constant, near
   K
5. Consequence High r Good competitors

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Small size Rapid growth Early reproduction Many,
small offspring Little parental care Large
size Slow growth Late reproduction Few, large
offspring More parental care
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K vs. r selection extremes in parental care
Humpback whales
Sea urchins
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B. Age distributions help tell if population is
growing or shrinking.
10.20
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Is this population growing or shrinking?
10.19
Cant tell for sure depends if age distribution
is stable or not
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Are age distributions typically stable?
10.21 Age distributions of large cactus finch,
Geospiza conirostris, on Genovesa Is., Galapagos
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C. Calculating rates of population change

• 1. Non-overlapping generations

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2. Overlapping generations life tables
(use board)
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End
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F. Points about exponential growth
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• Effects of Body Size
• a. Generation time

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b. Body size and r

• On average, small organisms have higher rates of
  per capita increase and more variable populations
  than large organisms.

11.21