Thermodynamics are at the heart of our understanding of ecosystemsHow ecosystems function An ecosystem is a community of lifeforms that interact in such an optimal way that how ecosystems function best, is when all components (including humans and other animals) can persist and live alongside each other for the longest time possible. Ecosystems are fuelled by the energy created by plants (primary producers) that convert the Sun's heat energy More and not an altogether difficult concept to grasp but one that isn’t widely taught to ecologists. Basically, all life on Earth, is derived from the Sun’s heat. This renewable energyEnergy and nutrients are the same thing. Plants capture energy from the Sun and store it in chemicals, via the process of photosynthesis. The excess greenery and waste that plants create, contain chemicals that animals can eat, in order to build their own bodies and reproduce. When a chemical is used this way, we call it a nutrient. As we More source constantly bombards ecosystems with energy but they would overheat, if it wasn’t for the absorptive capacity of food webs.
The laws of nature that determine how this all works, were popularised by Einstein in the early 1900s.
The first law of thermodynamics states:
In a perfectly isolated system, energy can change from one form to another but can never be created or destroyed.
Energy contained within a system will never disappear, just alter from one state to another and redistribute itself in a different way.
The second law of thermodynamics states that
the total entropyThe degree of disorder or chaos in a system, most often used to describe thermodynamic energy but also used the behaviour of information. All else being equal, physics determines that all matter and energy moves towards chaos, therefore biological systems are in a continual state of battling against entropic forces in order to remain stable. The most stable ecosystem is More of an isolated system can never decrease over time and is constant only if all processes are reversible. In other words, entropy forces energy to flow towards a state of greater chaos.
This last law is the most important.
There are two key principles to understand in this. The first is entropy. It’s a measure of the degree of disorder(Of energy and ecosystems). Ecosystems are thermodynamically driven. Disorder occurs when energy dissipates and becomes more chaotic. For example, the release of hot air into the atmosphere results in that energy is freer to disperse (maximum entropy). The opposite is true when energy is locked into biological processes, when it is stored inside molecules (minimum entropy). Stability in ecosystems occurs More in molecules. Molecules that are inside biologically systems are highly ordered. A tree branch has minimum entropy because the carbon is locked up as a lattice. This cools the planet. When a log decays, you release molecules into the atmosphere and this energy heats the planet.
Plants are on the front line of energy capture, so their potential to emit waste energy and increase the entropy of Earth’s biosphere is huge. Left alone, plants would destabilise their own environment. Until that is, animals evolved. The ability of animals to move from place to place and absorb the free surplus energyThe energy of a system that is emitted as waste and is not part of ecosystem processes. There is always some free surplus energy as this creates the basis for evolution where new species exploit gaps in the ecosystem where free energy becomes available. Surplus energy can occur as a result of disruption or disturbance. When free surplus energy reaches More created by plants, meant that ecosystems could reach a steady stable-state(of an ecosystem) where free surplus energy is minimised, where there is maximum entropy production and minimum waste. In such a system, there is expected to be relatively small fluctuations in atmospheric and other chemistry and where disruption or disturbance occurs, the resulting changes can be absorbed quickly by a succession of new plants and animals that enter to fill More. That’s one way of saying, that the amount of heat reaching Earth from the Sun, and the amount of heat absorbed by ecosystems, roughly balanced.
This point was only reached quite recently, after a few hundred million years of animal evolution.
