Visiting these environments it is possible to realize that nature
cannot be found only in the most obvious environments, but also in town it
is possible to perform interesting observations.
For instance
zonation, that we have already been able to observe in environments as the
salt marsh and the coastal strip, here can be observed in an even more
restricted environment, such as a stake stuck in the water. The variation
in the submerging and emersion periods is the main factor to determine the
disposition of the organisms along the solid substratum.
In the upper
part we initially meet organisms with terrestrial features, such as air
breathing, but that must be able to bear periodical submerging. That is
why these organisms are more provided with limbs that allow withdrawing
when the wave comes.
In the lower part we meet organisms with the
opposite problem: they are sea organisms, and cannot bear long periods of
emersion. For such reason they are provided with a shell that sticks
perfectly to the substratum, and in case of emersion they can keep a water
supply inside the shell that allows to them to survive until the water
submerges them again.
In this environment it is therefore possible to
introduce the concepts of:
· Zonation
· Adaptations
· Limiting factors
· Adaptations of the flora and the
fauna in the anthropic environments
· Sequence of the
colonization in the solid substrata (the fouling phenomenon)
· Diversity of the living
organisms.
