You should spend about 20 minutes on
Questions 1-13, which are based on Reading Passage 1
below. Walking with dinosaurs Peter
L. Falkingham and his colleagues at Manchester University are developing
techniques which look set to revolutionise our understanding of how dinosaurs
and other extinct animals behaved. The media image of
palaeontologists who study prehistoric life is often of field workers camped in
the desert in the hot sun, carefully picking away at the rock surrounding a
large dinosaur bone. But Peter Falkingham has done little of that for a while
now. Instead, he devotes himself to his computer. Not because he has become
inundated with paperwork, but because he is a new kind of palaeontologist: a
computational palaeontologist. What few people may consider is
that uncovering a skeleton, or discovering a new species, is where the research
begins, not where it ends. What we really want to understand is how the extinct
animals and plants behaved in their natural habitats. Drs Bill Sellers and Phil
Manning from the University of Manchester use a’genetic algorithm’- a kind of
computer code that can change itself and ‘evolve’- to explore how extinct
animals like dinosaurs, and our own early ancestors, walked and
stalked. The fossilised bones of a complete dinosaur skeleton
can tell scientists a lot about the animal, but they do not make up the complete
picture and the computer can try to fill the gap. The computer model is given a
digitised skeleton, and the locations of known muscles. The model then randomly
activates the muscles. This, perhaps unsurprisingly, results almost without fail
in the animal falling on its face. So the computer alters the activation pattern
and tries again … usually to similar effect. The modelled ’dinosaurs’ quickly
’evolve’. If there is any improvement, the computer discards the old pattern and
adopts the new one as the base for alteration. Eventually, the muscle activation
pattern evolves a stable way of moving, the best possible solution is reached,
and the dinosaur can walk, run, chase or graze. Assuming natural selection
evolves the best possible solution too, the modelled animal should be moving in
a manner similar to its now-extinct counterpart. And indeed, using the same
method for living animals (humans, emu and ostriches) similar top speeds were
achieved on the computer as in reality. By comparing their cyberspace results
with real measurements of living species, the Manchester team of
palaeontologists can be confident in the results computed showing how extinct
prehistoric animals such as dinosaurs moved. The Manchester University team have
used the computer simulations to produce a model of a giant meat-eating
dinosaur. It is called an acrocanthosaurus which literally means ’high spined
lizard’ because of the spines which run along its backbone. It is not really
known why they are there but scientists have speculated they could have
supported a hump that stored fat and water reserves. There are also those who
believe that the spines acted as a support for a sail. Of these, one half think
it was used as a display and could be flushed with blood and the other half
think it was used as a temperature-regulating device. It may have been a mixture
of the two. The skull seems out of proportion with its thick, heavy body because
it is so narrow and the jaws are delicate and fine. The feet are also worthy of
note as they look surprisingly small in contrast to the animal as a whole. It
has a deep broad tail and powerful leg muscles to aid locomotion. It walked on
its back legs and its front legs were much shorter with powerful
claws. Falkingham himself is investigating fossilised tracks,
or footprints, using computer simulations to help analyse how extinct animals
moved. Modern-day trackers who study the habitats of wild animals can tell you
what animal made a track, whether that animal was walking or running, sometimes
even the sex of the animal. But a fossil track poses a more considerable
challenge to interpret in the same way. A crucial consideration is knowing what
the environment including the mud, or sediment, upon which the animal walked was
like millions of years ago when the track was made. Experiments can answer these
questions but the number of variables is staggering. To physically recreate each
scenario with a box of mud is extremely time-consuming and difficult to repeat
accurately. This is where computer simulation comes in.
Falkingham uses computational techniques to model a volume of mud and control
the moisture content, consistency, and other conditions to simulate the mud of
prehistoric times. A footprint is then made in the digital mud by a virtual
foot. This footprint can be chopped up and viewed from any angle and stress
values can be extracted and calculated from inside it. By running hundreds of
these simulations simultaneously on supercomputers, Falkingham can start to
understand what types of footprint would be expected if an animal moved in a
certain way over a given kind of ground. Looking at the variation in the virtual
tracks, researchers can make sense of fossil tracks with greater
confidence. The application of computational techniques in
palaeontology is becoming more prevalent every year. As computer power continues
to increase, the range of problems that can be tackled and questions that can be
answered will only expand. Do the following statements agree
with the information given in Reading Passage 1 In boxes 1-6
on your answer sheet, write TRUE
if the statement agrees with the information FALSE if the statement contradicts the
information NOT GIVEN if there is no
information on this Research carried out into the composition of prehistoric mud has been found to be inaccurate.