Comparison with 1869 |
|
When a species, owing to highly favourable circumstances, increases inordinately in numbers in a small tract,
epidemics—at epidemics—at 1869 | epidemics— 1859 1860 1861 1866 1872 |
....... 1869 | at 1859 1860 1861 1866 1872 |
least, this seems generally to occur with our game
animals—often animals—often 1869 | animals— 1859 1860 1861 1866 1872 |
....... 1869 | often 1859 1860 1861 1866 1872 |
ensue: ensue: 1859 1860 1861 1866 1869 | ensue; 1872 |
and here we have a limiting check independent of the struggle for life. But even some of these so-called epidemics appear to be due to parasitic worms, which have from some cause, possibly in part through facility of diffusion amongst the crowded animals, been disproportionably
favoured: and here comes in a sort of struggle between the parasite and its prey. |
|
On the other hand, in many cases, a large stock of individuals of the same species, relatively to the numbers of its enemies, is absolutely necessary for its preservation. Thus we can easily raise plenty of corn and rape-seed, &c., in our fields, because the seeds are in great excess compared with the number of birds which feed on them; nor can the birds, though having a superabundance of food at this one season, increase in number proportionally to the supply of seed, as their numbers are checked during
winter: winter: 1859 1860 1861 1866 1869 | winter; 1872 |
but any one who has tried, knows how troublesome it is to get seed from a few wheat or other such plants in a garden;
I have in this case lost every single seed. This view of the necessity of a large stock of the same species for its preservation, explains, I believe, some singular facts in
nature, nature, 1859 1860 1861 1866 1869 | nature 1872 |
such as that of very rare plants being sometimes extremely
abundant abundant 1859 1860 1861 1866 1869 | abundant, 1872 |
in the few spots where they do
occur; occur; 1859 1860 1861 1866 1869 | exist; 1872 |
and that of some social plants being social, that
is, is, 1859 1860 1861 1866 1869 | is 1872 |
abounding in individuals, even on the extreme
confines confines 1859 1860 1861 1866 1869 | verge 1872 |
of their range. For in such cases, we may believe, that a plant could exist only where the conditions of its life were so favourable that many could exist together, and thus save each other
from utter destruction. I should add that the good effects of
frequent frequent 1859 1860 1861 1866 1869 | frequent 1872 |
intercrossing, and the ill effects of close interbreeding,
probably probably 1859 1860 1861 1866 1869 | no doubt 1872 |
come into play in
some some 1859 1860 1861 1866 1869 | many 1872 |
of these cases; but
on this intricate subject on this intricate subject 1859 1860 1861 1866 1869 |
OMIT 1872 |
I will not here
enlarge. enlarge. 1859 1860 1861 1866 1869 |
enlarge on this subject. 1872 |
|
Complex
Complex
1869 |
Complex
1866 1872 |
Relations
Relations
1869 |
Relations
1866 1872 |
of
all
Animals
Animals
1869 |
Animals
1866 1872 |
and
Plants
Plants
1869 |
Plants
1866 1872 |
to
each
other
other
1869 |
other
1866 1872 |
in
the
Struggle
Struggle
1869 |
Struggle
1866 1872 |
for
Existence.
Existence.
1869 |
Existence.
1866 1872 |
|
Many cases are on record showing how complex and unexpected are the checks and relations between organic beings, which have to struggle together in the same country. I will give only a single instance, which, though a simple one,
has has 1859 1860 1861 1866 1869 | has 1872 |
interested me. In Staffordshire, on the estate of a relation
where I had ample means of investigation, there was a large and extremely barren heath, which had never been touched by the hand of man; but several hundred acres of exactly the same nature had been enclosed twenty-five years previously and planted with Scotch fir. The change in the
|
When a species, owing to highly favourable circumstances, increases inordinately in numbers in a small tract,
epidemics— epidemics— 1859 1860 1861 1866 1872 | epidemics—at 1869 |
at at 1859 1860 1861 1866 1872 | at 1869 |
least, this seems generally to occur with our game
animals— animals— 1859 1860 1861 1866 1872 | animals—often 1869 |
often often 1859 1860 1861 1866 1872 | often 1869 |
ensue; ensue; 1872 | ensue: 1859 1860 1861 1866 1869 |
and here we have a limiting check independent of the struggle for life. But even some of these so-called epidemics appear to be due to parasitic worms, which have from some cause, possibly in part through facility of diffusion amongst the crowded animals, been
disproportionally disproportionally 1861 1866 1869 1872 | disproportionably 1859 1860 |
favoured: and here comes in a sort of struggle between the parasite and its prey. |
|
On the other hand, in many cases, a large stock of individuals of the same species, relatively to the numbers of its enemies, is absolutely necessary for its preservation. Thus we can easily raise plenty of corn and rape-seed, &c., in our fields, because the seeds are in great excess compared with the number of birds which feed on them; nor can the birds, though having a superabundance of food at this one season, increase in number proportionally to the supply of seed, as their numbers are checked during
winter; winter; 1872 | winter: 1859 1860 1861 1866 1869 |
but any one who has tried, knows how troublesome it is to get seed from a few wheat or other such plants in a
garden: garden: 1860 1861 1866 1869 1872 | garden; 1859 |
I have in this case lost every single seed. This view of the necessity of a large stock of the same species for its preservation, explains, I believe, some singular facts in
nature nature 1872 | nature, 1859 1860 1861 1866 1869 |
such as that of very rare plants being sometimes extremely
abundant, abundant, 1872 | abundant 1859 1860 1861 1866 1869 |
in the few spots where they do
exist; exist; 1872 | occur; 1859 1860 1861 1866 1869 |
and that of some social plants being social, that
is is 1872 | is, 1859 1860 1861 1866 1869 |
abounding in individuals, even on the extreme
verge verge 1872 | confines 1859 1860 1861 1866 1869 |
of their range. For in such cases, we may believe, that a plant could exist only where the conditions of its life were so favourable that many could exist together, and thus save
the species the species 1860 1861 1866 1869 1872 | each other 1859 |
from utter destruction. I should add that the good effects of
....... 1872 | frequent 1859 1860 1861 1866 1869 |
intercrossing, and the ill effects of close interbreeding,
no doubt no doubt 1872 | probably 1859 1860 1861 1866 1869 |
come into play in
many many 1872 | some 1859 1860 1861 1866 1869 |
of these cases; but
...OMIT 1872 |
on this intricate subject 1859 1860 1861 1866 1869 |
I will not here
enlarge on this subject. enlarge on this subject. 1872 |
enlarge. 1859 1860 1861 1866 1869 |
|
Complex
Complex
1866 1872 |
Complex
1869 |
Relations
Relations
1866 1872 |
Relations
1869 |
of
all
Animals
Animals
1866 1872 |
Animals
1869 |
and
Plants
Plants
1866 1872 |
Plants
1869 |
to
each
other
other
1866 1872 |
other
1869 |
in
the
Struggle
Struggle
1866 1872 |
Struggle
1869 |
for
Existence.
Existence.
1866 1872 |
Existence.
1869 |
|
Many cases are on record showing how complex and unexpected are the checks and relations between organic beings, which have to struggle together in the same country. I will give only a single instance, which, though a simple one,
....... 1872 | has 1859 1860 1861 1866 1869 |
interested me. In Staffordshire, on the estate of a
relation, relation, 1860 1861 1866 1869 1872 | relation 1859 |
where I had ample means of investigation, there was a large and extremely barren heath, which had never been touched by the hand of man; but several hundred acres of exactly the same nature had been enclosed twenty-five years previously and planted with Scotch fir. The change in the
|