442 KINSHIP AND ADAPTATION 
often connected in some helpful way with the life of the in- 
dividual—hairy appendages insuring to achenia widespread 
dissemination by wind, and the power to climb facilitating 
economically the quick exposure of green parts to sunlight. 
In such ways an organism, as we have seen, is adjusted, 
often marvelously well, to its environment; and we call the 
adjustments which promote its welfare adaptations. It is 
with questions of the origin and inheritance of adaptations 
that the debates of evolutionists are mainly concerned. We 
must, therefore, at the outset examine carefully just what is 
meant by an adaptation. 
Every individual plant or animal is found to have the 
power of modifying its form or behavior in response to out- 
side influences, and such modification is often beneficial. 
Indeed we need not distinguish here between form and 
behavior, for even structure is but the result of growing in 
certain ways, and growth is merely a slow kind of behavior. 
So we may say that each living thing, in so far as it is alive, 
has a certain limited power of adaptation through direct 
response to environing influences. As a seed sprouts, its 
little root turns toward the place of greatest moisture, while 
the young leaves are directed toward the light, and if the 
illumination be feeble the stem helps the leaves by elongating 
more than it would if the light were stronger. A tree exposed 
to strong winds of one prevailing direction takes on a one- 
sided form thereby reducing the strain. Herbs which in 
rich moist soil produce tall stems and ample foliage before 
they flower, will on a sandy roadside bloom as soon as they 
have made a few small crowded leaves and are only a few 
inches high, thus, doing the best they can under adverse 
conditions. Dandelions grown on a mountain side look very 
different from those grown in the lowlands (Fig. 301), and 
the peculiarities of each seem to fit in especially well with the 
contrasting conditions. Such cases of advantageous adjust- 
ment made during the life of an organism may be termed 
individual adaptations. From these we must distinguish 
characteristic adaptations, or advantageous peculiarities be- 
longing to whole groups. Of such adaptations the charac- 
teristics of clematis above referred to may serve as examples; 
