Ecology as a science is related not to environment studies or natural history; instead it is
akin to evolutionary biology and genetics. Ecology seeks to understand the dynamics between
species in an ecosystem and also that between the species and their natural environment. The
concepts of the movement of energy, associated chemical cycles, community structure in
question, the biodiversity and the ideas of succession are all interrelated and yet very disparate.
Together they provide insight into how the natural world operates.
Energy and Chemical Cycles
The concept of the flow of energy and that of the movement of individual elements via
chemical cycles are two ways of looking at exactly the same phenomenon. As elements move
through their respective chemical cycles in tandem, energy is produced and spent as well. The
element cycle also ensures that there is a balance maintained in the ecosystem. Three main
elements are relevant in the context of an ecological chemical cycle and the associated energy
The Oxygen cycle is balanced via a pair of complementary oxidation and reduction
reactions. These are more commonly known as respiration and photosynthesis respectively. In
the former, the free form of Oxygen combines with glucose or simple sugars to convert to
Adenosine-TriPhosphate, the currency of inter-cellular energy transfer. This is converted to
Adenosine-DiPhosphate when the energy has been consumed. Therefore, as Oxygen gets
consumed, the energy cycle makes progress as well (Ricklefs, 2005).
The reverse of this process is the process of photosynthesis. Chlorophyll based plants and
organisms are capable of conducting the process of photosynthesis, the process via which food is
made, quite literally out of thin air. As carbon molecules are trapped in this case (utilizing
Carbon Dioxide and demonstrating one of the finest ways of natural sequestration), Oxygen is
released into the air. It must be noted that plants don’t merely use photosynthesis to create food
for themselves and the other primary consumers. On the other hand, they too engage in
respiration, where they consume oxygen to burn some of this food. We see thus far that the
energy cycle runs parallel to the usage of Oxygen molecules. It must also be noted that the
amount of Oxygen consumed must be balanced with the amount of Oxygen returned back to the
atmosphere for the balance to be maintained.
The amount of Carbon that processes can utilize is fixed, but it is constantly being
converted into various forms and compounds to be cycled. As such none of the cycles are
independent of each other: Carbon, Oxygen and Nitrogen cycles all coexist and happen
simultaneously. Carbon gives structure and form to life beings. Released form of Carbon, when
it exists as Carbon Dioxide contributes to the green house effect, giving rise to calls for its
sequestration, or capturing in the solid form for burial under the ground. In deed, all too often,
cycles have a large buffer or warehouse where the cycled atoms may remain for a long period
before recycling; in the case of Carbon, this warehouse can be called to be underground, when it
is sequestered or exists as hydrocarbons. Atmospheric Carbon Dioxide is used by plants and
converted into sugars. This is the most important single step of the creation of “food”. This food
is eaten by the plant itself, or by some primary level creature and the food then moves on higher
up the food chain.
Nitrogen atoms move alongside Carbon and Oxygen, but meet their own peculiar feat
separate from that of the other two elements. Nitrogen goes from the soil to the organic bodies
and then into air. The element is needed for development and growth. Because of the inertness in
the gaseous form, Nitrogen is used in compound form from the soil. This nitrogen is either fixed
by bacteria or comes by way of Nitric Acid due to lightning strikes. When plants and animals die
and decay, this Nitrogen is released back.
The community structure would describe along spatial and temporal scales the modes of
interaction, the distribution, percentage of occurrence, structure of the various species that make
up a community. The association of populations can occur in various ways. Some relationships
are symbiotic, others are parasitic while still others are connected in complex ways that need
deeper examination to unravel. This interaction can be determined via genotypic or phenotypic
characteristics. This is also where the study of community ecology is focussed (Morin, 1999).
In order to study community structure, community ecologists look for patterns. These
patterns relate with variation in the richness of species, the structure of the food web,
productivity, equitability etc. Community structure could chart the locus for the movement of the
elements in their cycles as well as such facts about a restricted local community as the rate of the
completion of cycles, aspects that are sped up, aspects omitted etc. Therefore the concept of
community structure is not an isolated one, but one that affects chemical cycles and thus the flow
of energy. At the same time, local processes that enable the chemical chains, also construct or
destruct the assemblage of species, directly affecting the community structure.
Biodiversity indicates the extent of spectrum within life forms in an ecosystem. While
outwardly it may not be related to the other concepts already discussed, but it is the most
straightforward measure of the health of a biome or an ecosystem. Even though climate has a
part to play, but richness has to do with how well the chemical cycles are able to come about and
how much energy there is going around. For this reason, tropical ecosystems are richer than lets
say, polar ones. Biodiversity is severely affected when there are changes in the climate – also
affecting chemical cycles.
The concept of ecological succession is intricately connected to the concept of
biodiversity. There are many reasons behind changing of the structure of the species in a said
ecological community, most notably competition, time and need for climactic stability. New
habitat may be formed, which may induce rapid succession in an ecology, for example a volcano
eruption or an anthropomorphic disturbance like logging, deforestation etc. Succession can also
be primary or secondary, depending upon if the succession happened in a new habitat without
interference from the existing communities or if there was disruption to a pre-existing
community for succession of the new one (McEvoy, 2004).
The connection of succession with the other factors discussed above can be seen from
delving into auto-genic succession, which is actually catalyzed by changes in soil (brought about
by chemical cycles). These can include piling up of humus, change in pH etc. Allogenic
succession on the other hand is caused from environmental influences, which also are a
determinant to the biodiversity of the region. Animals influence such succession, via such acts as
pollination, grazing, shifting of soil (termites) etc. when animals we know also play a critical
role in all three of the chemical cycles (Barbour & Billings, 2000).
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