  From biosystem to complex system,the study of life is always an important
area. Inspired by hyper-cycle theory about the evolution of non-life system, we
study the metabolism, self-replication and mutation behavior in the Internet
based on node entity, connection relationship and function subgraph--motif--of
network topology. Firstly a framework of complex network evolution is proposed
to analyze the birth and death phenomena of Internet topology from January 1998
to August 2013. Then we find the Internet metabolism behavior from angle of
node, motif to global topology, i.e. one born node is only added into Internet,
subsequently takes part in the local reconstruction activities. Meanwhile there
are nodes' and motifs' death. In process of the local reconstruction, although
the Internet system replicates motifs repeatedly by adding or removing actions,
the system characteristics and global structure are not destroyed. Statistics
about the motif M3 which is a full connectivity subgraph shows that the process
of its metabolism is fluctuation that causes mutation of Internet. Furthermore
we find that mutation is instinctive reaction of Internet when it's influenced
from inside or outside environment, such as Internet bubble, social network
rising and finance crisis. The behaviors of metabolism, self-replication and
mutation of Internet indicate its life characteristic as a complex artificial
life. And our work will inspire people to study the life-like phenomena of
other complex systems from angle of topology structure.
