INTELLIGENT DEVELOPMENT 141
condensed by the cell’s signaling maze and then used to activate TFs, fol-
lowed by patterns of gene transcription. Th e gene transcripts are edited
and passed into the developmental machinery to construct, adapt, and
maintain the form of the cell, its organelles, and functions.
Similar pro cesses arise in the cells of multicellular organisms but are
much more amplifi ed. As with single cells, the spatiotemporally or ga nized
inside must be closely integrated with what is happening outside. But most
of the outside now consists of a multitude of neighboring cells and the
storms of signals from them. So the activities of each cell need to be inte-
grated and adjusted with what is going on in all the others. Th e plan—or
potential— for the emerging form of each cell cannot be predetermined
in the genes, because all cells contain the same genes. Instead it must be
created through the signaling traffi c going on among them— and there is
a lot of that.
Signaling between cells occurs through releases of chemical messages,
or ligands, into the extracellular spaces. In some cases, it occurs by direct
contact between neighboring cells, known as juxtacrine signaling. Para-
crine signaling is that which occurs over short distances. But most people
are familiar with endocrine signaling occurring over longer distances.
Th e signals have evolved to match with the cell surface receptors of other
cells (although a few can enter the cell directly through its membrane).
Th e docking of a ligand with its receptor results in signal transduction
and the activation of the second signaling system inside the cell, leading
to vari ous physiological responses.
Of course, what any individual stem cell needs to “know” is what kind
of cell to change into and where and when to do to it. In general terms
the pro cess is not about isolated signals as informational triggers or ele-
ments. Th at could not take the context of other cells into account, and
how they are changing. Instead, the signaling is structured in space
and time (spatiotemporal structure). In that structure is the deeper
information needed by recipient cells to determine their future states
in relation to the whole. Let us look at this pro cess a little more closely.
As a single cell, the young egg may look like a homogeneous sphere. But
there is already intelligence in the cell. For example, the apparent sphere
is already rendered uneven by the structure of its environment. Th e
point of entry of the sperm cell into the egg provides it with polarity—an
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