Slajd 1

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Species body weight relationships
Trichoplax adhaerens
Balaenoptera musculus
Loxodonta africana
Neotrombicula autumnalis
Goliathus regius
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Biogeographic distributions of body sizes
(Makarieva et al. 2005)
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Diversity and body size
Lord Robert May (1936-
Extinction rate
Speciation rate
z -2.0
ln (Population size)
Species richness
Body size species richness relationship in
metazoa
ln (Body size)
Body size
Smaller sized organisms should be species
richer. The species richness body size
relationship was assumed to be approximately a
power function with a slope of z -2
Metabolic theory predicts

• This hyopothesis assumes that
• either smaller sized species have a higher
  speciation rate or
• larger sized species ahave a higher extinction
  rate

Evolutionary speed should be higher in smaller
bodied species of the same population
sizes. Evolutionary speed is higher in small
populations.
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Species richness taxon body size relationship
Overall species richness body size relationship
z -0.5
Speciation driven
Speciation driven
Data from Orme et al. (2002)
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Species body weight relationships
Adult mammal female body weight
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Passive diffusion model (McKinney 1990)

• Body size evolution is a random walk on log
  transformed values
• There is a lower reflecting or absorbing boundary

• Right skew should be most pronounced in small
  bodied taxa
• Right skew should decrease with increasing
  species richness

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Coleoptera
Diptera
Hymenoptera

• Body size distributions of European Diptera and
  Hymenoptera are in accordance with the passive
  diffusion (boundary) hypothesis) with a lower
  boundary only
• Coleoptera appear to have a lower and an upper
  size boundary

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Models to explain obsered body weight
distributions in local habitats
Fractal habitats model (Morse et al. 1985)
Body size distributions of a local assemblage of
hymenoptera in a beech forest
z 0.43 0.02
z 0.72 0.06
z 0.50 0.01
Small bodied taxa should be most diverse The
slope should be between 0 and -1
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Todays reading
Body size and abundance www.biology.usu.edu/labsi
tes/ernestlab/PDFs/White_etal_2007.pdf Brose U.,
Jonsson T., Berlow E. L., Warren P.,
Banasek-Richter C., Bersier L.-F., Blanchard J.
L., Brey T., Carpenter S. R., Blandenier M. - F.
C., Cushing L., Dawah1 H. A., Dell1 T., Edwards
F., Harper-Smith S., Jacob U., Ledger M. E.,
Martinez N. D., Memmott J., Mintenbeck K.,
Pinnegar J. K., Rall B. C., Rayner T. S, Reuman
D. C., Ruess R., Ulrich W., Williams R. J.,
Woodward G., Cohen J. E. 2006. Consumer-resource
body-size relationships in natural food webs.
Ecology  87 2411 - 2417. pdf