‘
'
'CHAPTER XI
'
Â
'
ADAPTATIONS TO SUIT PARTICULAR CONDITIONS
”
IT has been indicated that many characters of
verte,—
bræ, form, ns, etc., have—arisen as a consequence of their :
movements.
Each individual ’ recapitulates the ancestral ‘
movements
and develops its, structure according ' to the
,
ancestral balance.
As they develop, some structures xor
consolidate the form of movement in a particular direction '
and may reach the dignity of adaptations.
,
‘
,
The term_“adaptation” has _both a general and:a
.
special sense.
.
We say that shes are ,“ adapted ”;to-iive'
in the water,
being
for… aquatic
_
-'
respiration, their tai1f
These qualies gare
a
,
similar
:;sày,ÿra--i,3;tonezç ifS
”
to ska »
,
ajcorkÏtoxaoat; —These_ general qualitiesar'e -
,,
_
fthmtprtglt ht thth
—
'arisenï
the f:phÿsical j laws of
reaction '
Without any—reference to their}? utility (vidé
'
_
To come nearer to the special— meaning : of the
.
adaptation, we may consider the opposite conditions: a
"
fish that has practicallÿ no gills (Monopterus) and a sh
,
,
that .;has practically no tail. (Sun—sh). These manage
to.
livequitewellby adapting thèirremaining structures toa
f
life. The former lives in the
,
the latter uses its dorsal andanal
ns,_for._‘propulsion in place of the lost caudàl.iInfa,if ;
welpictureÂtof_0urÿse1ves,what;a
.,
'
an»dhàhîts,Wé nd:that adaptations
reality
,
'
departu—re's,
.i‘n
o"r ’an0thert,
‘
'
As Professor ].— Arthur
it;
is
,
,
,