Biology Reference
In-Depth Information
past, thus providing the opportunity for evolutionary mechanisms such
as competition, mutation, hybridization, extinction, and geographic and
reproductive isolation to produce changes in organisms over time—the
Darwinian concept of evolution. In modern phraseology, “diversity within
clades . . . depends on age and thus the time available for accumulating
species” (Ricklefs 2007, 601). Communities of organisms, loosely aggre-
gated through similarities in ecological requirements, and with the oppor-
tunity to assemble, also project into the past, and their history offers clues
to their present status (Fine and Ree 2006) and analogs for anticipating
their future.
A third assumption is that achieving an understanding of ecosystems re-
quires, as the name implies, a systems approach. To a nonspecialist reading
some of the biological literature, it may occasionally seem that elevating
single factors to the status of causal events, sanctifying one approach over
another, bypassing previous studies to create an illusion of originality, or
presenting multiple factors in a “versus” context, is the modus operandi.
This is evident in such debates as climate versus the asteroid impact in the
demise of the dinosaurs, vicariance versus dispersal in biogeography, fossils
versus molecules in dating the divergence of lineages (II, chap. 8; Gillman
et al. 2009; Gill 2009), and other topics. In the initial euphoria of new-
found methods, their shortcomings and the priority and enduring strengths
of other approaches are sometimes minimized, and this paves the way for
their own marginalization with the next inevitable innovation. For what-
ever reason—whether it be a need to simplify to convey a sense of under-
standing or just ego-emissions—it is limiting to canonize the importance of
a single factor, approach, or person in explaining immensely complicated
processes when multiple factors are clearly involved. To paraphrase the
journalist H. L. Mencken, “For every complex problem there is a simple
solution. And it is always wrong.” That is, if the intricacy of the approach
or explanation does not match the intricacy of the problem, it is probably
an oversimplifi cation. As noted by Gröcke and Wortmann with reference
to the use of stable isotopes in investigating past environments, “The Earth
is an extremely dynamic system, with intimate links and feedbacks be-
tween the hydrosphere, atmosphere, biosphere, lithosphere and convecting
mantle. Integrative science is the future of paleoclimatic reconstructions,
and through such integration a better understanding of the dynamics of the
Earth System will emerge” (2008, 1). The same is true for understanding
the biogeography and evolutionary relationships of organisms. The need for
a rigorously balanced assessment of all relevant factors is generally under-
stood, but it is not always unambiguously stated and consistently followed.
Search WWH ::




Custom Search