Biodiversity is showing dangerous signs of expanding, like some B-movie
‘alien blob’, to fill the minds of Earth Summiteers and global conservation
managers. Such giant, slippery concepts tend to absorb energy and effort
at a level that has little effect on the ground, where species are lost
daily. So the International Council for Bird Preservation’s report Putting
Biodiversity on the Map comes as a welcome relief. It shows that international
organisations can focus global attention on regional sites in special need
of conservation action.

For the ICPB, the problem is that, in a world with a total land area
of 144 million square kilometres, not all birds are found everywhere, not
all are endangered, and funds and time are limited. How does it identify
the species and areas most in need of attention in an objective manner?
Birds have an advantage over other taxonomic groups. Firstly, the global
total of bird species is known to within plus or minus 1 per cent, and no
new large groups of species will appear to upset the analysis. Secondly,
we know the spatial distribution of species well enough to allow us to delineate
their ranges objectively. Thirdly, the ICBP is building on its long-standing
experience in processing regional information. This information is now
stored in a way that allows ‘every which way’ analysis with just a few
keystrokes, as the many maps and graphs of this report demonstrate clearly.

The ICPB focuses on critical sites by selecting (from the global total
of about 9000 species of birds) 2609 species of extant (or recently extinct)
landbirds with historical ranges restricted to less than 50 000 square
kilometres (the size of Sri Lanka). For these species, more than 50 000
locality records have been mapped and analysed to give 221 Endemic Bird
Areas, covering 6.5 million square kilometres (4.5 per cent of world land
area).

An EBA contains the ranges of two or more bird species that are entirely
restricted to that area. Size of EBAs range from 5 square kilometres, for
example, in the North West Hawaiian Islands to 170 000 square kilometres
in the Guianas. An EBA may contain up to 67 species that have a restricted
range (Solomon Islands). The ICPB then assesses the threat to these EBAs
in relation to the number of restricted range species, their taxonomic uniqueness,
endemism of other known taxa in the same area and how much of the area is
under protection. This allows the ICBP to pick out its top priorities from
a long list of candidates for conservation action. Here, global analysis
meets reality head on.

The report highlights the situation in Mexico, where only 6 per cent
of the area of 14 EBAs identified is protected, with 5 EBAs receiving no
protection at all within Mexico’s system of over 66 protected areas. The
ICBP report calls for more protection. But Mexico, forced to concentrate
its limited funds on problems of massive air and water pollution, must restrict
its ‘biodiversity’ attention to stabilising conditions in the ‘best’ 17
of these areas, and rather than expanding to include new areas. ICBP’s analysis
allows it to identify problems from an international perspective and then
assist local people to harmonise their development and conservation needs.
ICBP is opening offices in Mexico to do just that.

David Duthie lectures at Oxford Polytechnic.

Economic valuation of conservation and protected areas has emerged into
the public domain from a relatively small academic and international agency
background in the past few years. John Dixon and Paul Sherman’s book provides
a useful and accessible survey, with case studies of the economics of protected
areas.

They begin with a brief summary of the main economic values that might
be calculated for protected areas: direct, indirect, diffuse, and so on.
A similar section follows on the potential for, and difficulties of, actually
generating real figures for these valuations. Dixon and Sherman then provide
case studies from their previously published analysis of protected areas
in Thailand, looking at Khao Yai National Park, Thale Noi Non-Hunting Area
and Khao Soi Dao Wildlife Sanctuary. For each case, the authors attempt
to assemble economic values for the biodiversity, maintenance of ecosystem,
tourism, research and educational benefits of the protected area, before
balancing this against the cost of direct management and lost opportunity.
(the cost, for example, of forgoing the profits from raw materials such
as wood). A brief selection from research papers follows of similar valuations
of protected areas in the Virgin Islands, Australia and Korup National Park
in Cameroon.

Dixon and Sherman conclude that economic valuation of protected areas
may be useful but it is difficult to obtain data. Few protected areas are
attractive to entrepreneurs, but they may be socially useful through benefits
that flow to diffuse groups rather than individuals or private companies.
The authors emphasise that protection of areas is not guaranteed even when
the analysis is favourable, because benefits may not flow to the ‘appropriate’
quarters: that is, local people may still lose out.

There is no doubt that the accountants’ bottom-line approach to the
world could be of great value to environmental economists in the development
and presentation of arguments for the conservation of natural areas, especially
to government ministers. But, as a biologist, I still find it hard to overcome
some strong feeling of future dangers in the ‘price on everything’ approach.
Most conservationists are willing to price habitat even if they feel it
is priceless; they intuitively believe that valuation will guarantee protection.
Economists, by training, are much more ‘value neutral’. They make no judgment
as to whether a resource that has a monetary value should or should not
be exploited. By placing a price on protected areas we may simply be opening
them up to market forces. This is surely a dangerous step while valuation
techniques remain so frail and tentative – a prime example of A. N. Whitehead’s
fallacy of misplaced concreteness. For protected areas this could become
misplaced concrete.

David Duthie teaches biology in Oxford.

Aldo Leopold was one of the first people to champion conservation in
the US. He was a scientific game manager in the 1930s, then a wildlife conservationist
and, finally, until his death in 1949, a strong advocate of the need for
an ethical approach to the land as the basis for successful conservation.

The 59 pieces chosen by Susan Flader and J. Baird Callicott for The
River of the Mother of God from a total output of over 500 articles written
by Leopold range from the serious, published in peer-reviewed journals,
through quirky personal notes to small, selected audiences, to some trite
doggerel (luckily, just one piece). Each is prefaced by a brief note from
the editors outlining their view of its significance in the development
of Leopold’s environmental philosophy.

This collection is undoubtedly important in the purely academic sense
as it documents the work of one of the pioneers of an ecological attitude
which, hopefully, will become more, rather than less, prevalent. But I find
it difficult to recommend the book as a good read that is likely to bring
about the kind of change that Leopold worked for all his life.

Fortunately, a better read is available from the same pen. In 1949,
just a few months before he died fighting a fire on a neighbour’s farm,
Leopold finished editing a collection of essays and articles, called A Sand
County Almanac (Oxford, £12.95 hbk, £6.50 pbk). The almanac
reveals Leopold’s sharp attention to the practical details of ecology and
shows his strong emotions. It has become a conservation classic. A few lines
from this book can have more impact than the flood of environmental literature
currently threatening to drown us. If you have not read the almanac, and
are looking for something to renew – or ignite – your conservation fire,
then add it to your essential reading list.

David Duthie is a biology teacher.

A-Level Biology by WD Phillips and TJ Chilton, Oxford University Press,
pp 570, 11.95 Pounds pbk

Advanced Biology by J Simpkins and JI Williams (3rd edition 1989), Unwin
Hyman, pp 768, 15.50 Pounds pbk

Biological Science 1 and 2 by NPO Green, GW Stout, DJ Taylor; edited
by R Soper (2nd edition), Cambridge University Press, pp 972, 11.50 Pounds
(for each volume) pbk

Understanding Biology by G Toole and S Toole (1987), Hutchinson, pp
480, 11.50 pbk

University of Bath: Macmillan Science 16-19 Project: Microorganism and
Biotechnology by J Taylor, Macmillan, pp 200, 5.95 Pounds pbk

Applied Genetics by G Hayward, Macmillan, pp 240, 6.95 pbk

Biology: A Functional Approach by MBB Roberts (4th Edition), Nelson,
pp 694, 15.50 Pounds pbk

Biology Advance Topics by GH Harper, TJ King and MVB Roberts (1987),
Nelson, pp 172

Nuffield Advanced Science, Nuffield Chelsea Curriculum Trust: Revised
Biology: Study Guide I/II pp 468/606, 14.99 Pounds each volume; Teacher’s
Guide I/II pp 378/468, 21.95 Pounds each volume; Practical Guide 1: Gas
Exchange and Transport in Plants and Animals by B Geatrell, pp 64; Practical
Guide 2: Chemical Reactions in Organsims by R. Muley, pp 64; Practical Guide
3, pp 56; Practical Guide 4, pp 60; Practical Guide 5: Inheritance, pp 80;
Practical Guide 6: Development, Control and Integration, pp 64; and Practical
Guide 7: Ecology, pp 64. All Practical Guides cost 4.25 Pounds.

Systematics and Classification, General editor is Grace Monger;

Study Guide I & II, Nuffield, pp 96, 10.99 Pounds

Teachers’ Guide I & II, Nuffield, 19.50 Pounds

Biology education in Britain is teetering towards the end of the 20th
century increasingly in the public eye. A feeling is growing that some thing
is fundamentally wrong, which has produced significant changes in school
science. A growing flock of reformers, apologest and other carrion-feeders
now circle high above the weakened corpus of advanced level education. They
have yet to reveal their intentions so, until they do, the whole machinery
of education has to tread water.

For better or worse, however, A-levels will be with us for a few more
years. Each year schools still have to prepare their students for examination
using the textbooks at hand.

Schools and students cannot complain about a lack of choice in texts
for biology A-level: all the major educational publishers have produced
completely new texts or revised editions in the past five years. There are
now eight textbooks to choose from. But, despite this minor flurry of publishing
activity, none of the available texts is specifically geared towards coping
with the radical changes introduced by GCSE teaching at below 16 years old.
Rather the majority of the textbook revisions have been knee-jerk responses
to small adjustments in the syllabus by the examining boards, without major
reorganisation of the style and attitude of the basic text.

But we face the danger of missing new approaches to biology if publishers
continue to cultivate the syllabus-led textbook. There must be a real biology
out there somewhere, and there must be natural levels at which it can be
communicated meaningfully to different age-groups. A textbook should provide
this information. The role of the syllabus is to then focus the attention
of teacher and students on those aspects that are considered especially
important.

If we ask what we should be trying to achieve in biology education in
the 1990s, three important goals emerge. First, a textbook should provide
students with a working knowledge of the biological components of the world
around them. Secondly, biological materials should be vehicle for teaching
students ‘tools for thought’. Thirdly, we need to develop ambassadors for
biology; people sufficiently enthused with the subject to be willing to
try to explain the importance of biology to others who do not themselves
study it.

Without these street-level ambassadors, I doubt that newspaper and TV
coverage of biology will ever achieve much penetration into everyday awareness
and understanding.

Finally, we must remember the real world and add a fourth proviso: students
must perform adequately in the examinations set to test the syllabus.

If we accept these goals and then inspect the currently available textbooks,
they do not, in my opinion, fare too well, except perhaps on the fourth
goal.

For many schools in the country, a decision to replace M V B Roberts’
Biology: A Functional Approach, the clear market leader in the 1970s, has
still to be made, often because of financial constraints. The original text,
written in 1972, has now passed through four editions. It uses a supplement
of 20 advanced topics to bring it up to date with syllabus revisions and
present knowledge. Yet, despite its age and 1970 attitude to biology, when
coupled with the revised edition of the student practical handbook, the
complete Roberts package still provides a clear and easily accessible text
for a student to work from. If I was teaching in a school still using Roberts,
I might be tempted to stick with it until the muddied waters of 16-19 education
cleared.

Many of those schools which have moved on from Roberts have switched
to the two-volume package from Cambridge University Press Biological Sciences
I and II, revised in a second edition this year. Now, weighing in at just
under three kilograms – in paperback – and 964 pages long, Biological Sciences
probably provides enough facts to scrape through an undergraduate degree.
Couple this with a rather technical style, regularly interrupted by boxes
and longwinded practical exercises, supported by a multitude of ‘untrue-to-life’
diagrams, with just a thin smattering of real photos (in black and white
and often without scales) and you have the perfect text. That is, as long
as you subscribe to an ‘education as a series of hurdles, over which only
the the most superior and/or diligent deserve to climb’ school of thought.
I can recommend only that schools buy one or two copies for the library
and label them ‘best kept away from unaccompanied children’.

Of the other British texts, Simpkins and Williams’ Advanced Biology
has appeared in a third edition. Anyone put off this book by the incomplete
nature of the first edition, corrected in piecemeal style by the larger
second edition, should suppress their bias and give the third edition some
serious attention. It seems to be a natural replacement for Roberts, a little
more in line with the 1990 emphasis in biology, with an approachable style,
not too much detail, and evolving into a balanced, integrated text. The
biggest weakness of Simpkins and Williams (like Roberts and other British
texts) is that they have still to realise that molecular biology is much
more than ‘balls-and-sticks’ chemistry. Students could cope with it more
easily than us old-timers educated in a different way.

The only serious competition to the above three books is the new Macmillan/University
of Bath 16-19 integrated science project with two applied topics books specifically
aimed at the increasing number of option-based syllabuses. The main text
is due (hopefully’, to quote Macmillan) in Spring 1991. I passed the applied
topics books (in genetics and microorganisms/biotechnology) to colleagues
teaching in polytechnics, both of whom said that they would seriously consider
recommending them for their second year courses, while at the same time
expressing a strong desire that their incoming students had a better working
knowledge of the basics of their subjects. I wonder if the Macmillan core
textbook will be up to this challenge? If it is, and the writing is as clear
and friendly a style as that in the applied topic books, then Macmillan
may have a winner. That is, if A-levels survive long enough for it to recoup
its considerable investment in the project.

Occupying a niche all of its own, the Nuffield textbooks from Longmans
have been thoroughly revised. The Nuffield course provides an excellent
programme for training students to think and solve problems in biology,
but for it to work requires tremendous application by teachers, and experimental
and laboratory facilities beyond the pocket of many schools. Any teacher
looking for interesting practically-based material to introduce into their
normal teaching would do well to acquire a set.

As for the remaining British textbooks, there is little left to say.
They either fail to add much to pre-existing books (A-Level Biology) and
will find it difficult to establish a market foothold, or do not provide
a deep enough view of biology to stand alone as a textbook (Understanding
Biology). These books may, however, be useful for students who want to learn
only enough to pass an examination.

The only alternative to using ‘home-grown’ textbooks is to switch to
the biology undergraduate texts produced by the American universities. Some
of these books do not provide enough depth in particular areas to be adequate
for the present British A-level biology syllabus or, at 40 Pounds for a
paperback, are too expensive for schools even to contemplate buying. But,
in the light of the goals outlined above, most of the US textbooks are a
generation on from their British ‘equivalents’.

At the moment, the best value for money is Biology. For ‘just’ 17.95
Pounds in a paperback, you get more than three kilograms and 1400 pages,
with colour photographs and full-colour diagrams on every page, and a text
that is informative and explanatory, but hardly ever too technical.

The text manages to bring the hidden world of the cell into perspective,
while at the same time devoting more than 250 pages (17 per cent of the
total text) to the diversity of life. This is almost twice as much as most
British books provide (in black and white). any teacher confident that they
can teach the main core of the syllabus ‘up-front’ in class, would surely
appreciate being able to use this book to guide interested students into
extensions of biology, both back into history and out into the real world
around us.

The market in which textbooks have to operate has changed dramatically
in the past 15 years. Then, textbooks were a source of knowledge that had
little competition. Today’s sixth-formers can compare their textbooks with
a barrage of alternative media coverage, competing for their attention and
often covering the same topics. It is time the education business faced
up to the challenge of making the core of science teaching attractive in
this ‘free’ market. Sadly, the school report for British biology texts has
a familiar ring: ‘has the potential, could still do better.’

David Duthie tutors in biology A-level in Oxford.

The native range of the crown imperial fritillary extends from Turkey
to India. Alberto Burquez of the University of Cambridge, believes that
features of the fritillary indicate that it is bird-pollinated across its
entire range. This makes it the most northerly species of bird-pollinated,
or ornithophilous, plant to be reported so far.

Burquez observed crown imperials which were flowering in the university’s
botanic gardens during the springs of 1986, 1987 and 1988. Bluetits turned
out to be the most common visitors to the flowers, along with two species
of bumblebee, Bombus terrestris and B. lapidarius. Occasionally, two species
of finch visited the flower; Burquez was unable to identify them .

Only bluetits, which probe into the flower while hanging on the main
stem, are large enough, and have the right shape, to make regular contact
with both anthers and stigma. Other bird visitors act as nectar thieves,
ripping into the flower from above.

Burquez controlled the pollination of the plants that he selected by
placing a bridal veil over flower buds that were developing. Some flowers
he kept covered all the time. Others he self- or cross-pollinated using
a paintbrush. Still others he covered only after one potential pollinator
had visited the flower. He observed that the only flowers that set fruit
were those artificially cross-pollinated and those that were visited by
bluetits.

Crown imperial fritillaries secrete a large volume of dilute nectar.
In this respect, they resemble plants which botanists know are pollinated
by passerine, or perching, birds. Each flower may contain up to 8 millilitres
of nectar, 10 per cent of which is glucose and fructose. The nectar contains
no sucrose, which passerines find difficult to digest, and few amino acids.

Most other species of fritillary are pollinated by bumblebees and contain
sucrose and more amino acids in their nectar. The crown imperial, however,
is the only fritillary that botanists know of which does secrete sucrose.
According to Burquez, this indicates a specific adaptation to a different
type of pollinator.

The radial strands of the spider’s web are about 1 micrometre in diameter.
They are dry, non-sticky and stretch by only about 20 per cent of their
original length. The capture strands, on the other hand, are only 0.7 micrometres
in diameter and can stretch to four times their original length, then recover
with no obvious sag.

The key to this dramatic elasticity, say the researchers, lies in the
behaviour of the liquid which coats the fibres of silk protein. This coating,
which acts like a glue, consists of 80 per cent water plus a mixture of
lipid, amino acids and salts in solution. When the spider initially spins
out the thread of its capture spiral, the forces of surface tension in the
glue cause it to form spontaneously into small droplets, each enclosing
a tangled ball of silk fibres. This produces a taut web without any sag.

However when an ensnared insect stretches the capture spiral, the ‘spare’
fibre within the droplets unwinds. Initially, this increases the capture
spiral’s length enormously. Only when it is at maximum extension do the
fibres of silk protein themselves become stretched.

Because the strands of the capture spiral extend rapidly and recover,
the web is able to maintain its shape, even in strong winds. This property
also provides the web with the ‘give’ it needs to resist the escape of any
prey.

As far as researchers know, the ‘wet’ silk that is necessary to provide
this ability comes only from orbweb spiders, such as A diadematus.

HENRY Wadsworth Longfellow confesses his ignorance about ballistics
and trajectories, saying: ‘I shot an arrow into the air, where it fell I
know not where.’

This tongue-in-cheek observation opens Chapter 14 of Stephen Vogel’s
consistently entertaining progress report on a growing school of biological
research; that is, the comparative biomechanics of living organisms. It
serves to illustrate the author’s scampish approach to his subject. Researchers
in biomechanics are interested in the relationship between physics and the
living world, not so much because they suffer as biologists from supposed
‘physics envy’ and want to reduce living organisms to simple physical machines,
but rather because they realise that the rules of physics define some of
the boundaries of the complex ecological space that species attempt to fill.
For biomechanics, the ‘fitness’ of biological structures or materials lies
not just in their ultimate contribution to numbers of offspring produced,
but also in how closely they approach the theor-etical limitations imposed
by the rules of physics.

With a list of chapter titles that could easily have been lifted from
a standard physics text, Stephen Vogel has chosen to outline the basic physical
principles first, then illustrate these with selected examples from biology.
The presentation of the physics is clear, especially with respect to showing
how a final rule is derived from other form-ulae, yet requires only a knowledge
of a minimum of maths. As a bonus, Vogel usually manages to find a convenient
verbal description of a rule to assist the less mathematical reader. Thus
the sheer weight of physics begins to detract from the flow of the text
only in a chapter that defines physical variables. Having laid some firm
physical foundations, Vogel’s book comes alive as he moves on to consider
the ways in which organisms have evolved to cope with these constraints.

Naturally, the relationship between size and shape looms large in this
book. A whale has 1 million times less external surface area per unit volume
than did its primordial unicellular ancestor, or a present day unicell.
As organisms have evolved increased body size, they have of necessity been
selected for the development of enormous additional exchange surfaces such
as guts, gills, lung alveoli, root hairs and elephant ears, to compensate
for their otherwise shrinking surface area to volume ratio. This book covers
these classical areas well and probes some more obscure topics, but it fails,
surprisingly, to cover optics and sound.

One of the most impressive illustrations of biological use of physical
rules occurs when organisms have evolved direct equivalents to known physical
apparatus. In one example, Vogel uses Fick’s law of diffusion to show the
inadequacy of passive diffusion to supply oxygen to the depths of a prairie
dog burrow, then reveals the prairie dog’s clever solution to the problem.
By assiduously adjusting the height differential between the two openings
of their burrows, prairie dogs take advantage of slight breezes which generate
a ventilation flow through the burrow; the burrow is an exact parallel to
the physicist’s Venturi tube.

Perhaps the most important general insight that this book provides is
a warning to guard constantly against the natural biases that we bring to
our studies because of our own attributes. Humans sit very near to one end
of the size range for living organisms; the largest are only just over 10
times as big, yet the smallest organisms are a millionth our size. Different
organisms ‘feel’ physics in a different way to us, and anthropocentric thinking
will tend to mislead us.

Vogel takes us into the physical world of other organisms. For example,
he shows us how the smallest bacteria don’t need to move to feed, because
food molecules diffuse towards them more quickly than they absorb them.
But once they are moving, the concept of inertial free-wheeling cannot exist:
as soon as bacteria cease to propel themselves, friction drags them to a
halt in less than one atomic diameter. Insights such as these are sprinkled
throughout the book, and revive that feeling of joy in the face of biological
diversity which so often slips from our minds. Every species has some unique
story to tell us about how it survives in a complex world; where can we
find a greater source of intellectual stimulus? This book can provide you
with a flying start.

David Duthie is an environment biologist based in Oxford.