Page 33 - BBC Wildlife Volume 36 #02

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POINT

THE SPICE

OF LIFE

New research suggests we could share Earth with six billion other species. Entomologist
Ross Piper asks if we have radically underestimated our planet’s biodiversity.

illionaire technologists and bacteria (approximately 70–90 per cent of Mercator projection shows Greenland and
futurists who have read species) and insects are only one of many Africa roughly equal in size, but Africa is
too many comics fuel the hyperdiverse groups.” This whopping actually 15 times larger and, like everywhere
human ego with visions estimate embraces the enormous bacterial else, has many overlooked areas where few
of interstellar travel and diversity we find wherever we look, not to biologists have ever been.
terraforming the cold, dead mention parasites and the hyper-diversity Changing scale, now think about the
B dust of Mars. Theirs is a of insects, mites and nematodes. Animals structural complexity of a forest – the
jaded view of the Earth, a planet that has account for 163 million species. waterbodies, soil, roots, detritus, stems,
nothing left to offer, from which all the There are plenty of reasons why the boughs, leaves, bark and seeds. The variety
mystery has been wrung. Nothing could University of Arizona estimate is nearer of niches in a forest is mind-boggling.
be further from the truth. We have barely the mark. For starters, Earth is big. We Some of my work in Peru involves getting a
scratched the surface of understanding tend to forget just how big. Not only that, handle on this – exploring the extraordinary
our beautiful world, including how many but popular maps of our planet stretch diversity of animals that live in the
species we share it with. and distort, so that the landmasses are unfurling leaves of a couple of species of
To date we have formally described not shown as they really are. The standard understorey plants.
around 1.6 million species of living things,
broadly divided between three domains: ceans are a huge unknown, as
bacteria; archaea (single-celled microbes BBC One’s Blue Planet II recently
I
distinct from bacteria); and eukaryotes WE HAVE BARELY showed to dramatic effect, but
(animals, plants, fungi and protists even there we underestimate.
like slime molds). How many more are SCRATCHED THE OIt’s often said that we’ve explored
there? This question is one of the most around five per cent of the ocean, yet this
fundamental in science, but answering it SURFACE OF refers to the seabed and anyway is probably
is far from straightforward. The closer we an exaggeration. In fact, the whole volume of
Main illustration by Patrick George/Debut Art; sediment illustartion by Phil Miller
look at life on Earth, the more confusing UNDERSTANDING OUR the ocean is a habitat, and we’ve explored less
it becomes. Under scrutiny, even the term than one per cent of it.
‘species’ is a bit flaky. BEAUTIFUL WORLD. Not only is Earth enormous, but most
Regardless, answering this question has animals are small. Take the constellation
become something of a cottage industry in of sub-1mm animals that live between and
biology. For some reason, recent estimates on the sediment grains on the seabed:
of around 10 million species seemed to be the meiofauna. In one handful of this
meaty enough to satisfy the masses. But habitat there might be thousands of
they make enormous assumptions and individuals and representatives of more
more or less disregard the most diverse animal lineages than in an entire tropical
groups of organisms. rainforest. Our appreciation of life on Earth
Using a new approach, a team at the is completely skewed
University of Arizona has now come to Left: marine by our own size,
sediments are
the following conclusion: “There are likely but size has little or
alive with a
to be at least one to six billion species on constellation of no bearing on
Earth. The new Pie of Life is dominated by enigmatic animals. biological importance.

February 2018 BBC Wildlife 33