Info

106-108

10-5-10-3

Populations

10-2

10-2

102

108-1010

10-7-10-5

Ecosystems

10-4

10-4

104

1010-1012

10-9-10-7

1Openness, spatial scale, and time scale are inverse to hierarchical scale.

2Energy and matter exchange at each level depend on openness, measured as available exchange area relative to volume. Electromagnetic energy as solar photons comes in small packages (quanta, hv, where h is Planck's constant and v is frequency), which makes only utilization at the molecular level possible. However, cross-scale interactive coupling makes energy usable at all hierarchical levels. 3Openness correlates with (and determines) the behavioral frequencies of hierarchical levels.

1Openness, spatial scale, and time scale are inverse to hierarchical scale.

2Energy and matter exchange at each level depend on openness, measured as available exchange area relative to volume. Electromagnetic energy as solar photons comes in small packages (quanta, hv, where h is Planck's constant and v is frequency), which makes only utilization at the molecular level possible. However, cross-scale interactive coupling makes energy usable at all hierarchical levels. 3Openness correlates with (and determines) the behavioral frequencies of hierarchical levels.

to make the possible supply of energy sufficient (Figure 2.7). These considerations are consistent with the relationship between size and time scale of levels in the hierarchy, as presented by O'Neill et al. (1986) and Shugart and West (1981).

Exchange of matter and information with the environment of open systems is in principle not absolutely necessary, thermodynamically, as energy input (non-isolation) is sufficient (the system is non-isolated) to ensure maintenance far from equilibrium. However, it often gives the ecosystem some additional advantages, for instance by input of chemical compounds needed for certain biological processes or by immigration of species offering new possibilities for a better ordered structure of the system. All ecosystems are open to exchange of energy, matter, and information with their environment.

Spatial Extent: High Frequencies: Low

Minor Interactions Multiple Interactions

Filter

Constraints

Spatial Extent: Small Frequencies: High

Figure 2.7 A schematic representation of interacting hierarchical levels.

Spatial Extent: High Frequencies: Low

Minor Interactions Multiple Interactions

Filter

Constraints

Spatial Extent: Small Frequencies: High

Figure 2.7 A schematic representation of interacting hierarchical levels.

The importance of the openness to matter and information is clearly illustrated in the general relationship between number of species, SD (species diversity), of ecosystems on islands and the area of the islands, A:

where C and z are constants. The perimeter relative to the area of an island determines how "open" the island is to immigration or dissipative emigration from or to other islands or the adjacent continent. The unit (L-1) is the same as the above used area to volume ratio as a measure of openness.

Different species have very different types of energy use to maintain their biomass. For example, the blue whale uses most (97%) of the energy available for increasing the biomass for growth and only 3% for reproduction. Whales are what we call ^-strategists, defined as species having a stable habitat with a very small ratio between generation time and the length of time the habitat remains favorable. It means that they will evolve toward maintaining their population at its equilibrium level, close to the carrying capacity. ^-strategists are in contrast to r-strategists which are strongly influenced by any environmental factor. Due to their high growth rate they can, however, utilize suddenly emergent favorable conditions and increase the population rapidly. Many fishes, insects, and other invertebrates are r-strategists. The adult female reproduces more and the proportion going into reproduction can be over 50%.

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