For real changes to be seen, evolution takes at least tens of thousands
of years. So the secluded populations created by humans are still a
ways from providing noticeable changes.
Large animals with long generation periods and few offspring need large
stable territories to support a population large enough to maintain
genetic variation. As the forest fragments the larger mammals find their
populations less able to meet for genetic recombination so inbreeding
depression becomes a problem. Fragmentation and disturbances produce
smaller foraging territories with small populations with little
variation within each gene pool. Large mammals like moose a K
strategists in their life cycle.. K-strategists are niche resource
specialists meaning they are usually highly adapted rather than
generalists. They are resource partition adapters rather than emigraters
able to move on to another area with slightly different resources. Many
endangered species are K-strategists. Moose in fragmented forest would
be endangered along with other K strategists. Worms
are small, with a short life span but reproduce in large numbers as r
strategists. While they can readily disperse at the edges of the habitat
they will be much more likely to actually speciate with forest
fragmentation but each fragment will be large enough to support a
genetically diverse population of worms.
May 23rd, 2015
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