The didactic value of the urban environment
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
