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UNI101Y1 Study Guide - Species Pool, Gamma Diversity, Beta Diversity


Department
University College Courses
Course Code
UNI101Y1
Professor
Spencer Barrett

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BIO120H © Lisa Zhao 2011 | Page 2
larger islands are better targets for potential immigrants, and support larger pop.s
which may persist longer owing to their genetic diversity
LARGE-SCALE PATTERNS OF DIVERSITY REFLECT LATITUDE,
ENVIRONMENTAL HETERO GENEITY, AND PRODUCT IVITY
increases from N to S
greater heterogeneity of envmt in Western US provides more suitable consitions for a
greater # of species
Ecological Heterogeneity and Habitat Productivity
more productive (complex) habitat = more species
Solar Energy Input and Precipitation
B
Br
ra
ad
d
H
Ha
aw
wk
ki
in
ns
s et al.
solar NRG input influences species richness N of 15°
water availability had more influence on species richness in tropics through to SH
temp. relatively uniform in these areas
diff. in envmts mostly manifested through differences in precip.
p
po
ot
te
en
nt
ti
ia
al
l
e
ev
va
ap
po
ot
tr
ra
an
ns
sp
pi
ir
ra
at
ti
io
on
n
(P
PE
ET
T): the amount of water that could be transpired by
plants and evaporated from the soil, given the local temperature and humidity, if water
were not limited
describes the input of NRG into a system
energy-diversity hypothesis: there is a causal relationship b/w PET and species richness
more NRG can be shared by more species
DIVERSITY HAS BOTH R EGIONAL AND LOCAL CO MPONENTS
l
lo
oc
ca
al
l
d
di
iv
ve
er
rs
si
it
ty
y: a.k.a. alpha diversity; the number of species in a small area of
homogeneous habitat
r
re
eg
gi
io
on
na
al
l
d
di
iv
ve
er
rs
si
it
ty
y: a.k.a. Gamma diversity; the number of species observed in all
habitats within a large geographic area that includes no significant barriers to dispersal
b
be
et
ta
a
d
di
iv
ve
er
rs
si
it
ty
y: the difference, or turnover, in species from one habitat to another
Local Communities and the Regional Species Pool
s
sp
pe
ec
ci
ie
es
s
p
po
oo
ol
l: the entire group of species within a source region from which colonists of
an island or habitat patch are drawn
s
sp
pe
ec
ci
ie
es
s
s
so
or
rt
ti
in
ng
g: a process that determines membership in a local community based on
the tolerances of species from the regional species pool for local conditions, their
requirements for resources, or their interactions with competitors, predators, and
pathogens
ecologists in the
field
E
Ev
va
an
n
W
We
ei
ih
he
er
r
P
Pa
au
ul
l
K
Ke
ed
dd
dy
y
(species sorting
in wetland plant
communities)
sowed seeds of 20 species in 120 wetland microcosms (differed in
soil fertility, water depth, fluctuation in water depth, soil
texture, organic leaf litter)
# of species in each community decreased (due to competition)
diversity fell from 15 species to 3-5 species depending on soil
fertility
species composition differed since communities developed under
diff. envmts
thus, envmtal filters contribute to species sorting
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