Chapter 23
Gradient fields

Biological structures emerge through coordinated interactions between cells, chemical signals, and physical constraints.
These interactions generate organised patterns that guide the formation of tissues and organs.

This chapter explores pattern formation as the result of interacting biological fields operating across cellular boundaries during development.

Certain biological patterns arise from the interaction of chemical reactions and diffusion processes.
When substances react and spread through tissue simultaneously, stable spatial patterns can emerge.

This chapter examines reaction–diffusion systems, first described by Alan Turing, as mechanisms that generate repeating biological patterns such as stripes, spots, and developmental structures.

Cells determine their developmental roles by interpreting signals from their surrounding environment.
Through signalling molecules and regulatory networks, cells gain information about their location within the organism.

This chapter examines positional encoding as the process by which biological systems translate spatial information into organised developmental outcomes.