losing species

[Kristie Allen]

Mr. Brown,

You're absolutely right about us not losing bird or mammal species at 
that rate.  The species being lost are mostly insects, amphibians, and 
rare plants that have not even been cataloged yet.  The estimated rate at 
which we are losing 
species is based on biological studies in the rainforests and the rate 
at which we are finding and cataloging newly discovered species (which is 
phenomenal - hundreds of new species are found each 
time a rainforest canopy tree is examined).  The declining rate at which 
we find new species can be extrapolated into an estimate of the total 
number of species, which is used to estimate the rate of extinction by 
using a rate of habitat destruction (many of these species live in only 
one species of tree in one type of rainforest, while others are 
wide-ranging).
 
With increased population and corporation pressure to slash and burn 
rainforest for agricultural use, species we have never named are 
eradicated.  NO, I can't tell you which species were lost yesterday, 
noone can.  But, those species had probably been on this earth since 
before humans (humans are late-comers geologically and rainforests are 
ancient).

Speciation happens at a much slower rate than the present estimated rate 
of extinction.  Over geological time, however, the earth rarely has 
periods 
of low species diversity.  It rebounds from calamity quite quickly.  The 
earth, however, has never been faced with a species like homo sapiens 
before, which is intelligent, adaptable, and persistent about changing the 
surrounding environment to suite itself.  

Species would not be disappearing at nearly this rate if we were not 
around to "muck things up" unless a drastic global change were occurring.

Hope I helped to answer some questions.

Kristie L. Allen
Environmental Statistics Group
Biology Department
Montana State University
Bozeman, MT  59715   USA

Phone:  (406) 994-2332
E-mail:  kla at rivers.oscs.montana.edu
Internet:  http://rivers.oscs.montana.edu/esg/kla/klahome.html


On 23 Apr 1996, BROWN,DAVID,MR wrote:

> I recently read an article in the news paper that left me with
> a few questions I hope someone might be able to answer.  The article
> was concerning a recent U.N. report that claimed that the world is
> losing between 150 and 200 species a day.  This is not the first time
> I have heard such claims.  I realize that these are not species of
> mammals or birds that were losing.  I also realize the importance of
> every fungus and bacteria to the global ecological balance.  But
> my questions are these : 1) can someone, and I doubt that they can, give
> me an idea of which 175 or so species were lost yesturday? 2) How
> many species do we estimate that we gain each day through evolutionary
> changes or random mutations(same thing I guess)? 3) How is the figure
> of 150 - 200 species a day arrived at? 4) Is this a particularly high
> number, i.e. if we weren't around to muck things up, how many species
> would be dissapering each day?
> 
> Any light that could be shed on the subject would be much valued.
> Thank you,
> David Brown
> Montreal, Quebec
> 
> 
>