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Larvae distribution can complicate colonization
The rough
periwinkle and the amphibious
rock lice are examples of organisms that do not produce large numbers
of embryoes, but can nevertheless have the ability to establish themselves
well in remote areas. One difficulty with larval distribution is that they
quickly became sparcely distributed in the water. If a larva arrives at
a remote location without kin, there is a large chance that it will not
find anyone to mate with when it becames sexually mature and thereby cannot
result in a population increase and colonization.
Occasionally, a fertilized female can drift into a new area
and all of her young can be the new population. The problem is that if the
larvae have to develope in the water over a period of several weeks, they
run the risk of becaming dispersed and disappearing from the area. This
is not the situation when the embryo develope within the mother until the
time they are ready to start their own life on the beach. If for example
a fertilized female periwinkle comes to an area where other periwinkles
are absent, there is nevertheless a good chance that the periwinkle population
will increase. She, the female periwinkle can have several hundred embryo
within her shell and nearly all of the young she gives birth to will stay
in the same area. Here, they can mate with each other and if the environment
is favourable they can build a sizable population.
Many colony
building animals can effectively spread over large areas by means of fragmentation.
Organisms effect on each other
Organisms can effect each other by trying to
exploit the same resources, by eating each other and by building and forming
environments for each other.
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