  The continuity of life and its evolution, we proposed, emerge from an
interactive group process manifested in networks of interaction. We term this
process \textit{survival-of-the-fitted}. Here, we reason that survival of the
fitted results from a natural computational process we term \textit{natural
autoencoding}. Natural autoencoding works by retaining repeating biological
interactions while non-repeatable interactions disappear. (1) We define a
species by its \textit{species interaction code}, which consists of a compact
description of the repeating interactions of species organisms with their
external and internal environments. Species interaction codes are descriptions
recorded in the biological infrastructure that enables repeating interactions.
Encoding and decoding are interwoven. (2) Evolution proceeds by natural
autoencoding of sustained changes in species interaction codes. DNA is only one
element in natural autoencoding. (3) Natural autoencoding accounts for the
paradox of genome randomization in sexual reproduction -- recombined genomes
are analogous to the diversified inputs required for artificial autoencoding.
The increase in entropy generated by genome randomization compensates for the
decrease in entropy generated by organized life. (4) Natural autoencoding and
artificial autoencoding algorithms manifest defined similarities and
differences. Recognition of the importance of fittedness could well serve the
future of a humanly livable biosphere.
