of intestinal biofilms by pathogens can be very hazardous to health of the host. Those
interactions are dynamic and vary across a range of conditions, through space and
time (Coyte and Rakoff-Nahoum 2019). Infectious pathogens can even destructively
target the mitochondria of their victim (Escoll et al. 2017).
Sir Alexander Flemings’ discovery of the antimicrobial enzyme lysozyme (Fleming 1922) was a famously pioneering step towards the goal of understanding how
chemical warfare occurs between animals and potentially harmful microorganims.
Lysozyme is an N-acetylmuramide glycanhydrolase. It is produced by animals and is
part of the innate immune system. Lysozyme attacks the 1,4-beta-linkages between
N-acetylmuramic acid and N-acetyl-D-glucosamine of peptidoglycan. That attack
compromises bacterial cell wall integrity, resulting in lysis of the bacteria. A few
years later, Sir Alexander also discovered Penicillin (Fleming 1929) which represents part of the chemical battle that occurs between microorganisms. Discovery of
streptomycin by Waksman and his colleagues added another layer to our knowledge
of warfare between micobes (Waksman et al. 1946).
1.2.2 And the Struggle Is for Habitat and Niche
Life and all of its interactions represents a constant struggle for possession of habitat
and niche.
Each species will have a broadly defined potential habitat within which its
members will be restricted to a more narrowly defined operational habitat. Each
species also will have a broadly defined potential niche within which its members
will be restricted to a more narowly defined operational niche. Those concepts of
potential versus operational habitat and niche hold true at the genus level and on
upward through the higher taxonomic levels. The restrictions, from potential to
operational habitat and niche, occur because of competive exclusion caused by
other biological groups.
The interesting question for me becomes not why symbiotic associations develop,
but rather why those associations are not more widely present. Is it because they have
been limited by competitors? My presumption is that a species, and even its
symbiotic associations, will be found in all places except those from which it
specifically has been excluded. For example, there is a broad diversity of animals
in which Chlorella can establish itself as an ingested photosynthetic symbiont
(Chap. 26: The Game of Evolution is Won by Competitive Cheating). However,
there are many more animals which receive sunlight but do not form that interaction
with Chlorella, and the question becomes one of “Why not?”. If we could discover
what is preventing the formation of rhizobial nodules in other plants, then might we
be able to increase the range of crop plants in which rhizobial nodules can form, and
thus help reduce our reliance upon synthetic nitrogen fertilizers?
Long ago, when I began creating ceramic sculpture, which is done by sculpting
moist clay and eventually sintering that material in a kiln, I learned that the sculptor
can do anything which their medium allows. Perhaps the host and symbiont can do
10
C. J. Hurst
interactions are dynamic and vary across a range of conditions, through space and
time (Coyte and Rakoff-Nahoum 2019). Infectious pathogens can even destructively
target the mitochondria of their victim (Escoll et al. 2017).
Sir Alexander Flemings’ discovery of the antimicrobial enzyme lysozyme (Fleming 1922) was a famously pioneering step towards the goal of understanding how
chemical warfare occurs between animals and potentially harmful microorganims.
Lysozyme is an N-acetylmuramide glycanhydrolase. It is produced by animals and is
part of the innate immune system. Lysozyme attacks the 1,4-beta-linkages between
N-acetylmuramic acid and N-acetyl-D-glucosamine of peptidoglycan. That attack
compromises bacterial cell wall integrity, resulting in lysis of the bacteria. A few
years later, Sir Alexander also discovered Penicillin (Fleming 1929) which represents part of the chemical battle that occurs between microorganisms. Discovery of
streptomycin by Waksman and his colleagues added another layer to our knowledge
of warfare between micobes (Waksman et al. 1946).
1.2.2 And the Struggle Is for Habitat and Niche
Life and all of its interactions represents a constant struggle for possession of habitat
and niche.
Each species will have a broadly defined potential habitat within which its
members will be restricted to a more narrowly defined operational habitat. Each
species also will have a broadly defined potential niche within which its members
will be restricted to a more narowly defined operational niche. Those concepts of
potential versus operational habitat and niche hold true at the genus level and on
upward through the higher taxonomic levels. The restrictions, from potential to
operational habitat and niche, occur because of competive exclusion caused by
other biological groups.
The interesting question for me becomes not why symbiotic associations develop,
but rather why those associations are not more widely present. Is it because they have
been limited by competitors? My presumption is that a species, and even its
symbiotic associations, will be found in all places except those from which it
specifically has been excluded. For example, there is a broad diversity of animals
in which Chlorella can establish itself as an ingested photosynthetic symbiont
(Chap. 26: The Game of Evolution is Won by Competitive Cheating). However,
there are many more animals which receive sunlight but do not form that interaction
with Chlorella, and the question becomes one of “Why not?”. If we could discover
what is preventing the formation of rhizobial nodules in other plants, then might we
be able to increase the range of crop plants in which rhizobial nodules can form, and
thus help reduce our reliance upon synthetic nitrogen fertilizers?
Long ago, when I began creating ceramic sculpture, which is done by sculpting
moist clay and eventually sintering that material in a kiln, I learned that the sculptor
can do anything which their medium allows. Perhaps the host and symbiont can do
10
C. J. Hurst