Multicellular organisms cooperativity

A fundamental shortcoming should also be borne in mind transgenic organisms are made by altering one or a few genes, while it is the cell that has fiill attributes of autonomous replication. Further, in multicellular organisms this occurs in cooperation among differentiated cells. 

Cells are the fundamental units of life. They are functional entities, each of which is enclosed in a semipermeable membrane that varies in composition and function both over a single cell surface and between different cell types. There are two basic forms of cell prokaryotic and eukaryotic. Prokaryotes are most noted for their small sizes and relatively simple structures. Presumably because of these traits, in addition to their remarkably rapid reproduction rates and biochemical diversity, various prokaryotic species occupy virtually every ecological niche in the biosphere. In contrast, the most conspicuous feature of the eukaryotes is their extraordinarily complex internal structure. Because eukaryotes carry out their various metabolic functions in a variety of membrane-bound organelles, they are capable of a more sophisticated intracellular metabolism. The diverse metabolic regulatory mechanisms made possible by this complexity promote two important lifestyle features required by multicellular organisms cell specialization and intercellular cooperation. Consequently, it is not surprising that the majority of eukaryotes are multicellular organisms composed of numerous types of specialized cells. 

Multicellular organisms require sophisticated regulatory mechanisms to ensure that all their cells, tissues, and organs cooperate. For example, the feeding-fasting cycle illustrates how a variety of organs contribute to the acquisition of food molecules and their use. 

The presence of multiple levels of selection can therefore lead to the evolution of traits that appear altruistic at the individual level, as selective pressure at raie level may be offset by an opposing selective pressure at another level. Indeed, multilevel selection is thought to have contributed to major evolutionary innovations in cooperation, including the formation of cell-like systems and multicellular organisms [69-71]. 

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