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may often be a very 1859 1860 1861
has sometimes been a 1866 1869 1872

spreading of the 1859 1860 1861 1866
OMIT 1869

of life, which are those that oftenest vary, will in the long run 1859 1860 1861 1866
which spread widely and yield the greatest number of varieties will 1869

places of those groups of species 1859 1860 1861 1866
groups 1869

all the forms of life, ancient and recent, make together one grand system; for all are connected by generation. 1859 1860 1861 1866
all the forms of life, ancient and recent, make together a few grand classes; for all are at least thus far connected by generation. 1869
dominant forms which spread widely and yield the greatest number of varieties tend to people the world with allied, but modified, descendants; and these will generally succeed in displacing the groups which are their inferiors in the struggle for existence. 1872

1 blocks not present in 1859 1860 1861 1866 1869; present in 1872
Hence, after long intervals of time, the productions of the world will appear to have changed simultaneously.

from 1859 1860 1861 1866 1869
how it is that all the forms of life, ancient and recent, make together a few grand classes. We can understand, from 1872

living. 1859 1860 1861
living; why ancient and extinct forms often tend to fill up gaps between existing forms, sometimes blending two groups previously classed as distinct into one; but more commonly only bringing them a little closer together. 1866
living; 1869 1872

only bringing them 1859 1860 1861
bringing them only 1869 1872

descendants,
which form
and thus
new sub-groups and
groups.
groups
are
are
formed.
formed.
As these are formed, the species of the less vigorous groups, from their inferiority inherited from a common progenitor, tend to become extinct together, and to leave no modified offspring on the face of the earth. But the utter extinction of a whole group of species may often be a very slow process, from the survival of a few descendants, lingering in protected and isolated situations. When a group has once wholly disappeared, it does not reappear; for the link of generation has been broken.
We can understand how the spreading of the dominant forms of life, which are those that oftenest vary, will in the long run tend to people the world with allied, but modified, descendants; and these will generally succeed in
displacing
taking
the places of those groups of species which are their inferiors in the struggle for existence. Hence, after long intervals of time, the productions of the world
will
will
appear to have changed
simultaneously. &
simultaneously.
We can understand how it is that all the forms of life, ancient and recent, make together one grand system; for all are connected by generation. We can
understand
understand,
from the continued tendency to divergence of character, why the more ancient a form is, the more it generally differs from those now living.
why
Why
ancient and extinct forms often tend to fill up gaps between existing forms, sometimes blending two
groups,
groups
previ- ously
previously
classed as
distinct,
distinct
into one; but more commonly only bringing them a little closer together. The more ancient a form is, the more
often
often,
apparently,
apparently,
it
stands
displays characters
in some degree intermediate between groups now distinct; for the more ancient a form is, the more nearly it will be related to, and consequently resemble, the common progenitor of groups, since
become
be- come