... be only part of the story. It may also be necessary to under-
stand the underlying mechanisms (see Section 8. 10).
8. 8 Evolutionary effects of interspecific
competition
8. 8.1 Natural experiments
We ... in plots from
which the other species was removed (Figure 8. 4).
8. 2.6 Competition between diatoms
The final example is from a laboratory
investigation of two species of fresh-
wate...
... (°C)
20001900 188 0
–0.4
186 0
0.0
0.6
1.0
1920
Year
0 .8
0.4
0.2
–0.2
1 980 19601940
Figure 2.25 Global annual surface
temperature variations from 186 0 to 19 98.
The bars show departures from the mean
at ... sampled from diverse
localities in northern USA and Canada, and were tested for
freezing tolerance and ability to acclimate to cold. Individuals
from the most freez...
... 10
6
Spawning stock biomass (tonnes)
80 0
(c)
(d)
12
10
8
6
4
2
0
100 200 300 400
Net recruitment
(1000s)
Fin whale stock 5 years earlier (1000s)
0
Figure 5.10 Some dome-shaped
net-recruitment ... therefore trajectories that follow a cohort through
time. This is indicated by arrows, pointing from many small, young
individuals (bottom right) to fewer, larger, older individuals
(t...
... (Murton et al., 1966).
Individuals may also gain from living in groups if this helps to
locate food, give warning of predators or if it pays for individuals
to join forces in fighting off a predator ... bound to be compromises between
forces attracting individuals to disperse towards one another and
forces provoking individuals to disperse away from one another.
As we sha...
... times
take longer to respond to increases in prey abundance, and
longer to recover when reduced to low densities.
The same phenomenon occurs in
desert communities, where year -to-
year variations ... seeds,
mealworms, zooplankton relative to fish), it often fails to pre-
dict diets of foragers that attack mobile prey (small mammals,
fish, zooplankton relative to insect predators)...
... Charles Darwin ( 188 8) estimated that earthworms
in some pastures close to his house formed a new layer of soil
18 cm deep in 30 years, bringing about 50 tons ha
−1
to the soil sur-
face each year ... they would seem to constitute a high-quality
food resource. But they are not reingested by Chironomus larvae,
mainly because they are too large and too tough for its mouth-
parts to...