Activity 2.3- Biospheres and Interconnections
The Interconnections of energy and energy transformations in ecosystems
Energy exists in many different states, and is constantly making changes from one state to another. When energy is transforming it must obey the laws of thermodynamics, as they are universal. The first law is the law of conservation of energy, which states that energy cannot be create nor destroyed, only transformed. The second law of thermodynamics says the transformation of energy is always inefficient, and that life and ecosystems can't exist without a continuous energy input from outside sources (n.d.1).
All ecosystems have an energy budget, which focuses on the absorption of energy by photosynthetic organisms as well as the transformation of fixed energy through the trophic levels of the ecosystem. Trophic levels are the different levels of a food chain. Moving up in levels of the food chain results in a loss of about 90% of the starting energy at each transformation stage. The first level of this food web begins with the autotrophs, or primary producers (like leafy green plants, algae, etc.) which are the biological foundation of all ecosystems. Autotrophs can be further classified as either phototrophs or chemotrophs. Phototrophs utilize sunlight as an outside source for creating, or photosynthesizing, biomass, or food. Chemotrophs utilize certain organic chemicals to make biomass through a process called chemosynthesis. This initial amount of absorbed energy from outside sources by all primary producers in an ecosystem create what is known as gross primary production (GPP). Primary producers use this to carry out physiological functions needed to stay healthy and grow (n.d.2).
Net primary production (NPP)
is the fraction of GPP that remains for use after primary producers have used
what they need. The next step in the food chain is the heterotrophs who consume
plant biomass (Herbivores). These consumers will receive the highest
possible level of transformed energy, but their productivity levels will still
only be about 10% of that of the plants they consumed. Next is the heterotrophs
that consume animals (carnivores). These creatures are typically at the top of
the food chain, therefore they will have the lowest production levels in the
food chain and receive the lowest levels of energy from their food
sources (n.d.2).
The major loss of production
energy from one trophic level to the next brings up the issues of dwindling
food sources. As we analyze this issue in conjunction with the information we
learned about energy transformation loss, it is easy to understand that
choosing to utilize a diet that is based mostly on primary producers
(plants) is a more feasible option for sustainability of resources in the
future. The animals raised in the agricultural industry eat up a great deal of
cultivated grains. Some vegetarians argue that if people were to directly eat
these grains instead of feeding it to animals and then eating them, then we
would not need to use as much land for agriculture in order to sustain the human
population (n.d.2).
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