Darwin struggled with defining species and varieties in his work describing barnacles. He found the distinction between species and varieties to be vague and arbitrary. At times he would describe forms as distinct species only to later reconsider and describe them as one species or varieties. Determining priority of names for similar forms was also difficult work. While describing his cirripedia, Darwin did not feel that his doubts about the permanence of species affected his work much, though in some cases he would or would not have applied names depending on his views. He acknowledged that it was necessary work to apply Linnaean names to his barnacle species, and that understanding the importance of classification helped develop his theory of evolution.

1. Darwin,Darwin,
el ‘impedimentoel ‘impedimento
taxonómico, y lastaxonómico, y las
‘especies biológicas’‘especies biológicas’
Francisco Vergara SilvaFrancisco Vergara Silva

2. Sir Joseph Dalton Hooker, FRSSir Joseph Dalton Hooker, FRS
(30 junio 1817 – 10 diciembre 1911)(30 junio 1817 – 10 diciembre 1911)
http://en.wikipedia.org/wiki/Joseph_Dalton_Hooker

3. National Geographic, febrero de 2009

4. http://en.wikipedia.org/wiki/Barnacle
balanos,balanos,
percebes;percebes;
cirripedioscirripedios
1854.1854. Living Cirripedia,Living Cirripedia,
The Balanidæ,The Balanidæ,
(or sessile cirripedes);(or sessile cirripedes);
the Verrucidæthe Verrucidæ. Vol. 2. Vol. 2
http://darwin-online.org.uk
/EditorialIntroductions/Richmond_cirripedia.html
Robert E. Grant (1793-1874)Robert E. Grant (1793-1874)

5. a J. D. Hooker 12 de octubre de 1849
My dear Hooker,
(…)
I have of late been at work at mere
species describing, which is much more difficult
than I expected & has much the same sort of
interest as a puzzle has; (…)
What miserable work, again, it is searching for
priority of names; I have just finished two species
which possess seven generic & 24 species names!
My chief comfort is, that the work must be
sometime done, & I may as well do it, as anyone
else.-

6. a J. D. Hooker 25 de septiembre de 1853
My dear Hooker,
(…)
In my own cirripedial work (…) I have
not felt conscious that disbelieving in the
permanence of species has made much difference
one way or the other; in some few cases (…) I sh.d
not have affixed names, & in some few cases sh.d
have affixed names to remarkable varieties.

7. (…) Certainly I have felt it humiliating, discussing
& doubting & examining over & over again (…)
whether the form varied today or yesterday (…).
After describing a set of forms, as distinct species,
tearing up my M.S., & making them one species;
tearing that up & making them separate, & then
making them one again (which has happened to
me) I have gnashed my teeth, cursed speciescursed species, and
asked what sin I had committed to be so
punished. But I must confess, that perhaps nearly
the same thing wd.
have happened to me on any
scheme of work.-

9. http://en.wikipedia.org/wiki/Charles_Darwin
Darwin, C. R. 1860. On the origin of species by
means of natural selection, or the preservation of
favoured races in the struggle for life. Londres: John
Murray. 2ª. edición
Many years ago, when comparing, and seeing othersMany years ago, when comparing, and seeing others
compare, the birds from the separate islands of thecompare, the birds from the separate islands of the
Galapagos Archipelago, both one with another, andGalapagos Archipelago, both one with another, and
with those from the American mainland, I waswith those from the American mainland, I was
much struckmuch struck how entirely vague and arbitrary is thehow entirely vague and arbitrary is the
distinction between species and varietiesdistinction between species and varieties..

10. http://en.wikipedia.org/wiki/Charles_Darwin
It must be admitted that many forms, consideredIt must be admitted that many forms, considered
by highly-competent judges as varieties, have soby highly-competent judges as varieties, have so
perfectly the character of species that they areperfectly the character of species that they are
ranked by other highly-competent judges as goodranked by other highly-competent judges as good
and true species.and true species. But to discuss whether they areBut to discuss whether they are
rightly called species or varieties, before anyrightly called species or varieties, before any
definition of these terms has been generallydefinition of these terms has been generally
accepted, is vainly to beat the airaccepted, is vainly to beat the air..

11. A pesAr de que me pArecíA un
poco ‘engorroso’ AndArle
poniendo nombres linneAnos A
mis especies de percebes,
reconozco que erA necesArio…
¡entender lA importAnciA de lAs
clAsificAciones me Ayudó A
desArrollAr mi teoríA!

12. ¿qué son¿qué son
las ‘especies biológicas’?las ‘especies biológicas’?
¿son¿son realesreales
las especies biológicas?las especies biológicas?

15. Kress & ErikssonKress & Eriksson

16. http://www.dnabarcoding.ca/http://www.dnabarcoding.ca/

18. ‘‘crisis de biodiversidad’crisis de biodiversidad’
reto biológico de nuestra época –reto biológico de nuestra época –
preservar, continuar el legadopreservar, continuar el legado
de conocimiento taxonómicode conocimiento taxonómico
para futuras generacionespara futuras generaciones
el ‘impedimento taxonómico’ –el ‘impedimento taxonómico’ –
tasas mayores de extinción de especies;tasas mayores de extinción de especies;
menos taxónomos para estudiarlasmenos taxónomos para estudiarlas

20. GodfrayGodfray

22. Yo definía especies sin “pensar
evolutivamente”, ¡pero por supuesto
que consideraba la variación de los
caracteres de mis muestras de
herbario!

23. INECOLINECOL
BiologBiología Evolutivaía Evolutiva
de Cycadales &de Cycadales &
Genética deGenética de
PoblacionesPoblaciones
A. VovidesA. Vovides
J. González-AstorgaJ. González-Astorga
F. Nicolalde-MorejónF. Nicolalde-Morejón
© The Cycad Pages
J B Francisco JavierJ B Francisco Javier
Clavijero (Xalapa)Clavijero (Xalapa)
DioonDioon

24. DioonDioon

25. morfologíamorfología
moléculasmoléculas

26. Kirk FitzhughKirk Fitzhugh
http://www.nhm.org/research/annelida/staff.html
las especies biológicaslas especies biológicas
“no se ven”;“no se ven”;
las especies biológicas sonlas especies biológicas son
HIPÓTESISHIPÓTESIS
EXPLICATIVASEXPLICATIVAS
sobre las observacionessobre las observaciones
biológicasbiológicas
(morfológicas,(morfológicas,
moleculares, etc.)moleculares, etc.)

27. Estoy dE
acuErdo, kirk
agradecimientos -agradecimientos -
UNAMUNAM
Dra. Susana Magallón (IBUNAM)Dra. Susana Magallón (IBUNAM)
f.vergarasilva@gmail.comf.vergarasilva@gmail.com

29. http://www.eco-pros.com/biodiversity-genetic.htm

30. Aadi-maxi (lengua otomí), bachuga (lengua cuicatleca), be-thoxi, bi-
tuixi, pe-thoxi, bichoaxhe,pe-thoxe (lengua zapoteca), ha'sikil-p'ak,
p'ak, ts'ulub'p'ak (lengua maya), tuthay, tuthey (lengua huasteca),
mbaremoxu (lengua mazahua), paclshá (lengua totonaca), shitumal,
xitomat (dialecto náhuatl), xitomatl (lengua náhuatl), tzajalpish
(lengua tojolobal), xayuqui-te (lengua huichol), xucúpara (lengua
tarasca)
http://www.conabio.gob.mx/malezasdemexico/solanaceae/lycopersicon-esculentum/fichas/ficha.htm#1.%20Nombres

31. http://www.conabio.gob.mx/malezasdemexico/solanaceae/lycopersicon-esculentum/fichas/ficha.htm#1.%20Nombres
Solanaceae
Lycopersicon esculentum P. Mill.
(= Solanum lycopersicum L.)
Jitomate silvestre