The Pyramid of Life (Levels of Biological Organization) Help
Introduction to The Pyramid of Life (Levels of Biological Organization)
Prominent among Biological concepts was the notion of Biological Order – a particular pattern associated with living things. Recall that the spotted body pattern of a giraffe was used to symbolize Biological Order within the individual organism. And a spider in its web represented Biological Order extending outward beyond the organism. This elegantly simple visual pattern suggested a criss-crossing network of linkages existing among various living things in the external environment.
Now it is time to consider still another pattern, one well-known to the Ancient Egyptians. Of course, you have already guessed it! It is the distinctly pointed-and-sloped pattern of the pyramid:
The pyramid shape consists of a number of horizontal levels, stacked one upon the other. This stacked pyramid is sometimes used in biology to help model the various levels of biological organization. A level of biological organization represents a certain degree of size and complexity of body structures, as well as the inter-relationships between them and other non-body structures. In biology, a Pyramid of Life can be identified. This Pyramid consists of 12 stacked horizontal levels of biological organization (Figure 2.1, A). Observe that these levels are numbered from bottom-to-top (Levels I-XII). Level XII, the peak of the Pyramid of Life, is the largest and most complex. This position at the top or peak symbolizes the fact that Level XII contains all the other levels of biological organization below and within it. Further, each of the other levels likewise contains the lower levels closer to the broad base of the Pyramid. The farther one goes up in the Pyramid, the greater is the size and complexity of the biological patterns encountered.
“Why is this diagram called the Pyramid of Life?” you may well ask. The reason is that life begins at a certain level of the Pyramid (Level V), and then continues upward through each of the higher levels of biological organization (Levels VI–XII). As Figure 2.1 (B) shows, the 12 Pyramid levels are as follows: subatomic (sub-ah- TAH -mik) particles, atoms, molecules, organelles ( OR -gah- nels ), cells, tissues, organs, organ systems, organism, population, community , and ecosystem ( E -koh- sis -tem). Figure 2.1 (C) labels and tags certain levels in special ways. For example, Level V (cells) is labeled as “The Life-line.” This indicates that the cell is the lowest living level of biological organization. All levels above this “Life-line,” therefore, also include living things. Note, too, that the spotted giraffe (Biological Order) icon appears alongside Levels I–IX. This is because the giraffe, as an organism (Level IX), includes all the lower levels (organ systems down to subatomic particles) within it. Finally, observe that the spider in its web icon occurs beside Levels X–XII. The explanation is that a population, community, and ecosystem are all above the organism level of the Pyramid.