Quote 1
How have
all those exquisite adaptations of one part of the organisation
to another part, and to the conditions of life, and of one distinct
organic being to another being, been perfected? We see these beautiful
co-adaptations most plainly in the woodpecker and missletoe; and
only a little less plainly in the humblest parasite which clings
to the hairs of a quadruped or feather of a bird; . . . in short,
we see beautiful adaptation everywhere and in every part of the organic
world.
This quotation from Chapter III addresses
the way in which variations in a species influence the “perfect”
adaptation of an organism to its environment. In the previous two
chapters, Darwin explains the different types of variations seen
in plants and animals that help scientists distinguish between varieties
and species (although Darwin argues that the distinction between
the two categories is fundamentally arbitrary). In this quotation,
he says that these variations not only produce distinct varieties
of species but also create species that are uniquely adapted to
their environments. Woodpeckers, mistletoe plants, and parasites
have adapted structures (the beaks of woodpeckers, for example)
that allow them to maximize their access to nutrients and therefore
to survive. The term “co-adaptations” implies that species adapt
to one another. For example, the hair or feathers of animals adapt
the texture that allows a parasite to cling. Variations, therefore,
cannot be random.
