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Unformatted text preview: Ecology, Lecture 3: How many individuals in a population?
Births Deaths Demography & Life History
Forces affecting individual abundance in populations How to estimate population size Dispersion of individuals in populations Metapopulation dynamics Population Size Emigration Life tables and survivorship curves Life history tradeoffs and traits Immigration Births and immigration add individuals to a population Deaths and emigration remove individuals from a population
1 2 Absolute Density: Total Counts Absolute Density: Sampling Methods 3 4 Mark-Recapture Method Estimation of total population size (N)
Marked inds. in 1st sample (m) / Total population size (N) = Marked inds. in 2nd sample (x) / Total caught in 2nd sample (n) m = inds marked and released m/N = x/n N = mn/x N = (12 * 15) / 4 x=4
x = marked inds recaptured N = 45 1st sample 2nd sample
m = 12
n = total inds captured (in 2nd sample) n = 15 5 6 Density and body size Density Estimates: Relative 7 8 Radio collars Tracking movement: PIT tags 9 10 Population dispersion patterns Pattern of dispersion Uniform Clumped Random 11 12 13 14 Dispersion patterns are dependent on scale! Uniform distribution in plants — allelopathy and resource competition 15 16 The metapopulation concept
A group of spatially separated populations that interact through immigration and emigration Butterﬂy metapops. in Finland Individuals Habitat patches A metapopulation is a population of populations
17 Glanville fritillary (Melitaea cinxia)
18 ˚ Hanski & Meyke 2005 Aland Islands Demography
The study of the vital statistics of a population, and how they change over time “Deme” is another term for a group of interbreeding organisms 5 km Occupied patch Unoccupied patch
19 20 Life Tables
1,000 Number of survivors (log scale) Survivorship Curve 100 Females 10 Males A cohort is a group of individuals of the same age
21 1 0 2 4 6 Age (years) 8 10 22 Survivorship Curve Types
Number of survivors (log scale)
1,000 I 100 II
1 0 50 100 A giant clam discharging eggs on the Great Barrier Reef
23 Percentage of maximum life span
24 Survivorship Curve Examples Reproductive Table 25 26 Life history trade-offs
Parents surviving the following winter (%)
100 Male Female
80 60 40 20 Evolution of demographic traits
Reduced brood size Normal brood size Enlarged brood size
27 28 0 Odonturus dentatus Iteroparous
iterare (to repeat) Semelparous
semel (once), parere (to beget) Tityus falconensis “Century plant” (Agave americana)
29 30 31 32 Coconut palm (Cocos nucifera) Dandelion (Taraxacum sp.)
33 34 ...
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This note was uploaded on 09/04/2010 for the course CHEM 10966 taught by Professor Vollhardt during the Spring '10 term at Berkeley.
- Spring '10