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Dr.
Steven J. Hageman
hagemansj@appstate.edu
Ph: 1+(828)
262-6609
Fax:1+(828) 262-6503
Department
of
Geology
Appalachian State Univ.
PO. Box 32008
Boone, NC 28608
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Steve Hageman
Professor
of
Geology
Appalachian State University
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Research
Program
My research efforts have been divided
between two
programs:
- The first is an investigation of
microevolutionary
patterns and processes. I use morphometric
methods applied to
fossil invertebrates (Bryozoa) to document
subspecific morphologic
variation and incorporate empirical observations
into revised models
for microevolution and speciation. The
colonial nature of
bryozoans allows for study
of the sources of morphologic variation, which
are not possible to
resolve
with solitary fossil organisms. Work to date has
demonstrated that
remarkably
high-level resolution of morphologic variation
from fossil material can
contain
meaningful signals about genetic and
microenvironmental influences.
- The second part of my research involves
the distribution and ecology of Bryozoa.
This study differs from
the
first in that the level of interest is
spacio-temporal taxic variation
(species and genera). The modern southern
Australian continental
shelf provided the opportunity to evaluate the
ecology and distribution
of an extremely diverse
bryozoan fauna (400+ species, 77+ families, 3
orders in one
study). Bryozoa play a dominant role in
the benthic ecosystem and
carbonate sediment production in this
province. I have used
Bryozoa from this province to develop a
multi-dimensional,
morpho-ecological space which can be used to
characterize and evaluated
life modes of this Phylum (refined derivative of
traditional growth
form analysis). This approach has proved
viable and effective in
the study of broader ecological patterns in the
southern Australian
Temperate Province. This methodology was
integral in recognizing
and understanding ephemeral substrates (host
animals with cuticular or
spiculate skeletons) as a primary source of
sediment production in this
cool-water carbonate
province.
I plan to continue both phases of
my research
(subspecific-morphologic and taxic-ecologic), with
the intention of
integrating them into a unified program.
I have an ongoing research
project with colleagues
in Scotland (C. Todd and M. Bayer), who have grown
replicate, cloned
bryozoan colonies in controlled environmental
conditions. The
morphometric work we are doing with this material
will provide
important
insights about phenotypic and genotypic controls
over
morphogenesis.
This type of data is key to understanding
microevolution and speciation
(implications well beyond Bryozoa). In the
future I would like to
perform such studies on a larger scale, with an even
greater control on
the genetics involved.
The Australian work has provided
me with a standardized mopho-ecological frame-work
(based on
species-level
observations), with which to map bryozoan life-modes
through time and
space.
I have begun to apply this to the fossil record
(Miocene of southern
Australia).
I have several projects planned which will track
important sediment
forming cheilostome bryozoan life modes (~clades)
from their origins in
the Late
Cretaceous and Early Tertiary, through their
development as important
carbonate
sediment formers and major players in the benthic
ecosystem of large
areas.
This study is important both for an understanding of
a the evolution of
our
modern ecosystem and comparison to the important
stenolaemate bryozoan
sediments of the Paleozoic of North America.
I am continuing studies of
geographic variation,
community succession and paleoecology in cyclic
shelf and epeiric
marine sediments: Oligo-Miocene of southern
Australia and
Permo-Carboniferous of the mid-continent of North
America.
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