Tuesday, January 29, 2013

Ecological systems: an example from Africa

Here's a quick post to review the concept of systems, in this case ecological systems, which were mentioned in the last post.

An ecosystem, like other systems, is a collection of interdependent and interconnected parts that function as a unit and involve inputs and outputs. It is also complex and needs all its parts and intricacy to work properly.

In the case of an ecological system, the living parts -- animals, plants, fungi -- interact with each other and with abiotic (non-living) parts -- the air, water, and mineral soil -- through the transfer of nutrients and energy.

Here's a simplified example:

1. A lion in eastern Africa eats a topi antelope, taking in the nutrients, water and energy of the antelope.

2. The lion continues to eat topis for a few years (and is justifiably unwelcome at antelope parties).
3. The lion dies, and its nutrients and energy are transferred to vultures and to the soil, where bacteria and other microbes break down the organic material left by the vultures and convert it to soil nutrients.

4. Wind carries grass seeds to this same patch of soil, while the sun beams down energy to the whole area.

5. The grass seedlings absorb water, nitrogen and other nutrients from the soil, and carbon dioxide and solar energy from the air and combine them through photosynthesis to produce sugar and grow.

6. An antelope of the future eats the grass and converts the energy (sugars) and water from the plants into its own tissue.

7. Repeat as needed. Requires additional grass, gazelles, lions, vultures, microbes, soil, wind, sun, and water to carry on.



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