The Herdman Geological Society hosts it's prestigious annual
symposium on Saturday March 4th in the Earth
Sciences Department of The University of Liverpool.
This year's event is on the theme of "the origin of life"
and will consist of lectures from five guest speakers
from universities around the country. The topics covered
will include early life, the geochemical origins of life,
the fossil record, the first land plants and animals, and
the question "what came first, the dinosaur or the egg?".
Programme of Events:
10.30 am Assemble for tea and coffee.
10.55 am Welcome and opening comments.
11.00 am Speaker one - Prof. Michael Russell.
12.00 am Speaker two - Dr. Nick Butterfield.
1.00 pm Buffet lunch.
1.45 pm Speaker three - Prof. Dianne Edwards.
2.45 pm Speaker four - Dr. Ivan Sansom.
3.45 pm Tea and coffee break.
4.00 pm Speaker five - Dr. Martin Whyte / Prof. Zhang
5.00 pm Open debate and closing comments.
"Reconstructing the Cambrian Explosion: The Early Evolution
of Animal Ecology" - Dr. Nick Butterfield, Cambridge University.
The "Cambrian explosion" of large animals marks the
fundamental division in Earth history, not least because of
the profound ecological restructuring that must have
accompanied their introduction. The appearance of
multicellular heterotrophy, for example, would have
initiated a positive ecological and evolutionary feedback
loop, not only inducing counter-responses among primary
producers, ("top-down" effects), but paving the way for
primary and secondary carnivores. This in turn would have
induced marked increases in organism size, activity and
defensive strategies, all with major environmental effects.
Directly or indirectly, the fossil record documents a
number of the key steps in the evolution of metazoan
ecologies including benthic and planktic herbivory, and
primary, secondary and even tertiary carnivory. All of
these were achieved by at least the Early Cambrian
indicating the rapid emplacement of more or less
modern-styled metazoan ecosystems. The key distinction
between Early Cambrian and more recent trophic structures
appears to be the lack of the web-like interconnectedness
in the former. Paradoxically, simple chain-like trophic
structures are fundamentally more susceptible to
perturbation (as in modern trophic cascades), a condition
that may account for the rapid evolutionary turnover of
Cambrian faunas.
"The Early History of Vertebrates" - Dr. Ivan
Sansom, University of Birmingham.
The canonical view of Palaeozoic fish is one of an initial
appearance during the Ordovician, followed by a gradual
evolutionary radiation during the Silurian and Devonian,
giving rise to the "Age of the Fishes". Recent work in North
America augmented by similar studies based in Australia and
the former Soviet Union, challenges the timing of this
diversification, and suggests that it was initiated at least
40 million years earlier, during the Ordovician, following the
first record of vertebrates in the Late Cambrian. The hitherto
enigmatic conodonts are now firmly placed within
the vertebrate clade, and specimens from the Burgess Shale
and Chenjiang lagerstatten are forcing their way into
consideration.
The rapid recent progress in this field has been largely driven
by a change in emphasis and methodology, from the study of
whole animals to the collection and identification of
disarticulated microremains. As a consequence of this, the
fossil record of major groups of fish, such as sharks,
thelodonts and heterostracans is now known to extend
back deep into the Ordovician, as opposed to the Silurian.
In addition, studies of microremains from the Early
Silurian are beginning to yield a number of higher
taxonomic groups which were hitherto unknown. Preliminary
studies also suggest that the Early Palaeozoic represented
a time of experimentation with tissue types and tissue
combinations in the primitive vertebrates.
"The Green Revolution: Plants Invade the Land" - Prof.
Dianne Edwards, Cardiff University.
Recently accumulated evidence suggests that the invasion of
the land by photosynthesising organisms was a
gradual process, beginning in the Precambrian and ending in
the diversification of vascular plants in the Devonian. I
propose to review the evidence for successive and
overlapping phases of colonisation, to reconstruct the
nature of the resulting vegetation and to assess its impact
on the terrestrial environment in terms of substrate (e.g.
evolution of soils) and atmosphere (e.g. levels of C02).
"Dinosaur Eggs, A Chinese View" (Which came first, the
dinosaur or the egg?) - Dr. Martin White / Prof. Zhang
Zhenyu, University of Sheffield.
Which came first the dinosaur or the egg? However you answer
this, eggs are a reminder of life's repeated origin
and continuity. Dinosaur eggs, now known from over 200
sites world wide, are fascinating fossils and provide
evocative evidence of the life styles and life cycles of
these animals. In this talk we will review our joint
research on the dinosaur eggs of Henan Province and compare
and contrast these results with discoveries elsewhere.
The 'Amber Basins' of the late Cretaceous of Henan, including
the Xixia, Xiaguan and Lingbao basins, are one of
the premier sites for dinosaur eggs in the world, in terms
of both quantity and quality of material. The eggs were
laid in fluvial sediments deposited in narrow intra-montane
basins with a warm seasonal climate. Within these
sequences there are also occasional pieces of bone but only
one footprint has so far been found. Several different
types of egg occur and show varied evidence of dinosaur
nesting and brooding habits.
Different groups of dinosaurs have different sizes and shapes
of egg and different eggshell structures. As well
as reflecting their evolution the form of the eggs is
related to their nesting behaviour. The eggshell is a
shelter, which must protect the developing embryo and yet
allow exchange of gases with the exterior. Many dinosaur
eggs show damage on the upper side and the chicks appear to
have hatched. Occasionally intact eggs are found and these
are associated with skeletal material it is possible to
link eggs with particular dinosaur types. Other
associations of eggs and hatchling or adult skeletons may
also shed light on these relationships.
Tickets are priced £4 and are available from Ian Bamber or
the organisers, Kathryn Warren ([log in to unmask])
and Roy Davies ([log in to unmask]).
More information is available on the web at:
http://www.rasdavies.co.uk/symposium.html
----------------------
Ian Bamber
Departmental Co-ordinator
Department of Earth Sciences
University of Liverpool
4 Brownlow Street
Liverpool
L69 7GP
Tel: +44 (0) 151 794 5162
Fax: +44 (0) 151 794 5196
[log in to unmask]
http://www.liv.ac.uk/earth_sciences/dept/general.html
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