
Arguing about species: Is it evidence, or ego? - Hooke
http://johnhawks.net/weblog/topics/taxonomy/species-argument-evidence-ego-2017.html
======
teekert
To argue about species is to argue about definitions and to argue about
definitions is to create paradoxes.

For example: A and B (and C) are the same species when they can produce
offspring creates these questions:

\- What if A and B produce infertile offspring

\- What is A and B can reproduce, B and C can reproduce by A and C can not?

We humans and our need to put lines on continuous stuff, we keep ourselves
busy with such futile things.

~~~
crusso
Just because an abstraction isn't perfect or it can be misused doesn't mean
that it can't also be vitally useful in many circumstances.

~~~
TeMPOraL
Exactly. But endlessly bitching about the precise border is a waste of time,
because all of our abstractions (including words in every language) break if
you zoom in too close on them. People need to learn to live with soft, fuzzy
boundaries on concepts.

------
reptation
Especially for prokaryotes, how to define what is a species is an active
problem in the philosophy of biology. IIRC, Laura Franklin-Hall at NYU has
written about this ([https://as.nyu.edu/faculty/laura-rebecca-
franklin.html](https://as.nyu.edu/faculty/laura-rebecca-franklin.html)). In a
research setting this is far from a trivial question. One lab's E.coli may
show different characteristics than another lab's, even if they are the same
strain.

~~~
toolslive
Philosophers have been pondering on the definition of 'human' (and other
categorizations) for at least 2000 years.

The relation with this problem is that you can offer the following attempt at
definition: "it's human if the direct ancestors are human". Of course, it
fails ;)

Another attempt is via attributes (fe, "if it has a head, arms, legs, and an
IQ of at least X and DNA that has ..., it's human"). This also quickly fails.

I think the current consensus amongst philosophers is that a binary
categorization is impossible in these cases. ie, whatever the definition, you
will either exclude things you want to be included and/or include things you
don't want in there.

~~~
etplayer
What are the current edge cases for 'human' and 'non-human' which makes the
line so blurred that our common sense is no longer sufficient to judge, and we
need to invoke philosophy, and further philosophy without input from biology?

~~~
eesmith
There are a set of questions about when human life starts. Is it when the
sperm touches the egg? When the zygote forms?

There is no firm answer, and the choice depends on one's philosophy. The US
Supreme Court - and in this case I am suggesting that the courts are a sort of
applied philosophy - took input from biology in deciding Roe v. Wade.

Medical ethics, again a form of philosophy, says that human embryo
experimentation must not continue past two weeks, based on input from biology.
That's when the central nervous system starts to form, and marks the end of
when the embryo can split into twins. It was also not believed possible to
keep an embryo alive outside the womb that long, but now it's possible.
[http://www.npr.org/sections/health-
shots/2017/03/02/51628089...](http://www.npr.org/sections/health-
shots/2017/03/02/516280895/embryo-experiments-reveal-earliest-human-
development-but-stir-ethical-debate)

If the definition of human is related to DNA, then is cancer human? What about
immortal cell lines? Parasitic cancers like Canine transmissible venereal
tumor?

Were Neanderthals human? Denisovans?

------
nonbel
The selection pressure will be towards more and more species since it has more
clickbait potential: "New human ancestor species discovered in Africa",
"Ecologists discover 10,000 new bacterial species in a hydrothermal vent",
etc.

I really don't see any pressures currently in favor of "lumping". I guess just
inertia.

~~~
eesmith
I ... don't think you have much experience with the issue?

"Until the late 1980s, as many as 32 subspecies were recorded; genetic study
of mitochondrial DNA[35] found many of these are too similar to be recognized
as distinct at a molecular level. Following the research, the canonical Mammal
Species of the World (3rd ed.) recognizes six subspecies, five of which are
solely found in Latin America" \-
[https://en.wikipedia.org/wiki/Cougar#Subspecies](https://en.wikipedia.org/wiki/Cougar#Subspecies)

There is a continuous question of if a given "species" is really a distinct
species, and thus protected under the Endangered Species Act, or if it's a
subspecies or hybrid. There is political pressure to lump, because of the cost
of protecting a species. Some examples of lumping:

"Extensive studies conducted by researchers at the Denver Museum of Nature and
History have shown that the Preble meadow jumping mouse is not a distinct
species from other common mice and does not deserve protection under the
Endangered Species Act." \-
[http://www.citizenreviewonline.org/jan2004/rodents.htm](http://www.citizenreviewonline.org/jan2004/rodents.htm)

Is the grey wolf really a distinct species?
[https://phys.org/news/2016-07-gray-wolf-endangered-
species-g...](https://phys.org/news/2016-07-gray-wolf-endangered-species-
genomic.html) .

"The Fish and Wildlife Service (Service) under the authority of the Endangered
Species Act of 1973 (Act), as amended, proposes to remove the plant
Echinocereus lloydii (Lloyd's hedgehog cactus) from the Federal List of
Endangered and Threatened Plants. Lloyd's hedgehog cactus was listed as
endangered on October 26, 1979, due to threats of collection and highway
projects. Recent evidence indicates that Lloyd's hedgehog cactus is not a
distinct species but rather a hybrid. Therefore, Lloyd's hedgehog cactus does
not qualify for protection under the Act." \-
[https://www.gpo.gov/fdsys/pkg/FR-1996-06-14/html/96-15124.ht...](https://www.gpo.gov/fdsys/pkg/FR-1996-06-14/html/96-15124.htm)

~~~
nonbel
Interesting, thanks.

