University of Auckland, “Naming ” ©201

 Passage 1 is adapted from The University of Auckland, 
“Naming Species before Extinction.” ©2013 by The 
University of Auckland. Passage 2 is adapted from Geoffrey 
Giller, “Are We Any Closer to Knowing How Many Species 
There Are on Earth?” ©2014 by Scientific American, a 
division of Nature America, Inc.
Passage 1
Claims that most species will go extinct before 
they can be discovered have been debunked by 
researchers in an article published in Science.
The scientists show that the claims are based on 
two key misconceptions: an over-estimation of how 
many species may exist on Earth, and the erroneous 
belief that the number of taxonomists (people who 
describe and identify species) is declining.
“Our findings are potentially good news for
the conservation of global biodiversity,” says lead 
author Associate Professor Mark Costello from The 
University of Auckland, who published the work 
with Professor Nigel Stork from Griffith University 
and Professor Bob May from Oxford.
The authors propose that there are 5, plus or 
minus 3, million species on Earth—far fewer than
has been widely believed—of which 1.5 million 
species have been named. This re-affirms previous 
estimates by the three authors, which spanned the 
upper and lower reaches of this range.
“Over-estimates of the number of species on
Earth are self-defeating because they can make 
attempts to discover and conserve biodiversity 
appear to be hopeless,” says Dr. Costello. “Our work 
suggests that this is far from the case. We believe that 
with just a modest increase in effort in taxonomy and 
conservation, most species could be discovered and 
protected from extinction.”
The authors conclude that there have never been 
so many people describing new species—including 
professionals and amateurs, the number may
near 50,000. And the community continues to grow, 
in large part due to the development of science in 
Asia and South America, regions that are rich in 
biodiversity and where many new species are being 
discovered.
While the research suggests that species are more 
likely to be discovered than to go extinct, the authors 
do not underplay the seriousness of the threats to
species and their habitats. The combination of 
over-hunting, habitat loss and climate change, now 
occurring at both local and global scales, means that 
extinction rates could increase very rapidly in the 
future.
Dr. Costello says that the discovery and naming
of species is critical to their conservation. Naming a 
species gives formal recognition to its existence, 
making its conservation far easier.
Passage 2
Julian Caley, a researcher at the Australian 
Institute of Marine Science, and his coauthors looked 
at published estimates of the total number of species 
in the world as well as reckonings of the number of 
terrestrial insects, terrestrial arthropods, marine 
species and coral reef–dwelling species. Within each 
group, the researchers found that there was no 
indication that the estimates were converging on a 
number or a range.
The main problem, Caley says, is that new 
estimates usually fail to take previous work into 
account. “No one really refers to the information 
that’s already gained,” he says. Caley also points out 
that many of these past estimates used multiple 
different techniques to arrive at their estimates, 
including extrapolations based on the density of 
species in a study area or the rate at which new 
species are being discovered and described. But a 
larger problem is that many are just single-number 
estimates. Normally, he explains, statistical 
calculations have an associated margin of error. This 
range incorporates the likelihood that the actual 
number of species is not, say, five million—it could 
be five million plus or minus three million, for a total 
range of two million to eight million species globally. 
(This was, in fact, the estimate of one paper that 
included a range.)
The team calls for future estimates to include 
these ranges and to be statistically based, instead of 
what they call “simple best guesses.” When taking 
past work into account, the authors wrote, estimates 
that are not statistically based should carry less 
weight or possibly be excluded altogether.
Nigel Stork, a professor at Griffith University, is a 
coauthor of the paper that gave the two million to 
eight million species range. Stork agrees about the 
need for improved statistical approaches when 
making estimates. He takes issue, however, with 
Caley’s conclusion that there is no convergence of 
global species estimates. “[Caley] says that the global

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