present all that is known. I have summarized a few of the highlights in this essay, and
hopefully you will enjoy reading it. At least, the photographs will seem nice!
The other symbioses that I have included are: fungal symbionts of plant roots,
gastrointestinal symbiont microbes, luminescent bacterial symbionts, and endogenous viruses.
26.1.4 Ultimately, Evolutionary Fitness Is a Competition
for Habitat and Niche
For a biological group at any taxonomical level, there will be both a broadly defined
potential habitat within which that group is restricted to a more narrowly defined
operational habitat, and a broadly defined potential niche within which that group is
restricted to a more narrowly defined operational niche. Those restrictions which
limit the habitat and niche from their broader potential levels to narrower operational
levels are largely delineated by other species (Hurst 2016a).
The increased competitive fitness which derives from successful cheating may
allow an expansion of either habitat, or niche, or both. That expansion might be
represented in the claiming of a greater operational habitat and operational niche, or
become even more significant by representing an inrease in the potential habitat and
potential niche.
If competitive failure reduces a biological groups operational habitat or operational niche too severely, then that biological group faces possible extinction.
26.2 The Basic Concepts of Symbiosis
We think of symbiosis as being the ‘living together’ of two organisms which may
represent different species, and each organism is termed to be a symbiont. Bernhard
Frank seems to have been the person who initially named this concept when he
included the term ‘Symbiotismus’ in a landmark publication (Frank 1877). Figure 26.1 is a photograph of Albert Bernhard Frank. He was born January 17, 1839 in
Dresden, Germany and died September 27, 1900 in Berlin, Germany.
When Frank wrote his landmark publication (Frank 1877) he was considering
lichens, which most typically are bipartite composite organisms consisting of a
fungus partnered with either an algae or cyanobacteria. There also are tripartite
lichens that consist of a fungus partnered with both an algae and a cyanobacteria. I
will again mention the lichen symbiosis later in this essay.
Frank (1877) suggested that there were stepwise levels of symbiotic association
from the most loose to the deepest possible necessary connection. Frank called the
lowest stage pseudoparasitism ‘Pseudoparasitismus’ and suggested that was
represented by epiphytes. The next higher level would be parasitism ‘Parasitismus’
548
C. J. Hurst
hopefully you will enjoy reading it. At least, the photographs will seem nice!
The other symbioses that I have included are: fungal symbionts of plant roots,
gastrointestinal symbiont microbes, luminescent bacterial symbionts, and endogenous viruses.
26.1.4 Ultimately, Evolutionary Fitness Is a Competition
for Habitat and Niche
For a biological group at any taxonomical level, there will be both a broadly defined
potential habitat within which that group is restricted to a more narrowly defined
operational habitat, and a broadly defined potential niche within which that group is
restricted to a more narrowly defined operational niche. Those restrictions which
limit the habitat and niche from their broader potential levels to narrower operational
levels are largely delineated by other species (Hurst 2016a).
The increased competitive fitness which derives from successful cheating may
allow an expansion of either habitat, or niche, or both. That expansion might be
represented in the claiming of a greater operational habitat and operational niche, or
become even more significant by representing an inrease in the potential habitat and
potential niche.
If competitive failure reduces a biological groups operational habitat or operational niche too severely, then that biological group faces possible extinction.
26.2 The Basic Concepts of Symbiosis
We think of symbiosis as being the ‘living together’ of two organisms which may
represent different species, and each organism is termed to be a symbiont. Bernhard
Frank seems to have been the person who initially named this concept when he
included the term ‘Symbiotismus’ in a landmark publication (Frank 1877). Figure 26.1 is a photograph of Albert Bernhard Frank. He was born January 17, 1839 in
Dresden, Germany and died September 27, 1900 in Berlin, Germany.
When Frank wrote his landmark publication (Frank 1877) he was considering
lichens, which most typically are bipartite composite organisms consisting of a
fungus partnered with either an algae or cyanobacteria. There also are tripartite
lichens that consist of a fungus partnered with both an algae and a cyanobacteria. I
will again mention the lichen symbiosis later in this essay.
Frank (1877) suggested that there were stepwise levels of symbiotic association
from the most loose to the deepest possible necessary connection. Frank called the
lowest stage pseudoparasitism ‘Pseudoparasitismus’ and suggested that was
represented by epiphytes. The next higher level would be parasitism ‘Parasitismus’
548
C. J. Hurst