Introduction
Technology is a complex system, composed of more than one entity or sub-systems of technologies and a relationship that holds between each entity and at least one other entity in the system for achieving specific goals (cf., Coccia, 2019, 2019a; Coccia and Watts, 2020). Technology evolves by inventions of new things and new ways of doing things (originated from advances in basic and applied sciences) that are transformed into usable innovations in markets to satisfy needs, achieve goals and solve problems of adopters (Coccia, 2019). 
Technological innovation, underpinned in technology, can be categorized in different typologies, given by (Coccia, 2005, 2020): incremental innovations (progressive modifications of existing products and/or processes); radical innovations (a drastic change of existing products/processes, or creation of new products to satisfy needs or solve problems in society); technological systems (a cluster of innovations that are technically and economically inter-related, e.g., nanotechnology or biotechnology); technological revolutions (pervasive changes in technology affecting many branches of the economy, such as Artificial Intelligence having a technological dynamism and a pervasive use in a wide range of sectors; cf., Coccia, 2015, 2015a, 2017, 2017a, 2018, 2018a, 2019b, 2020). Technological innovations generate technological change that is the progress of technology by incremental, radical and disruptive innovations for achieving consequential goals and/or fostering economic and social change. Each technology, within technological change (driven by manifold technologies), evolves. Next section presents some theories.
Evolution of technology
The evolution of technology generates new and/or improved products or processes (technological innovations) to satisfy increasing needs of people and/or to solve complex problems of organizations, supporting human progress (Sahal, 1981).
Technological evolution can be explained with:
- Traditional theories based on processes of competitive substitution of a new technology or innovation for the old one.
- New theories based on a multi-mode interaction between technologies or innovations, such as the theory of technological parasitism by Coccia (2019), Coccia and Watts (2020).
First approach is based on traditional theories that consider the evolution of technology is a process of actual substitution of new technology/innovation for the old one. 
Fisher and Pry (1971, p. 75) purport that technological evolution can be due to a process of technological substitution between emerging and established technologies/innovations, such as the substitution of wired with wireless headphones, etc. Pistorius and Utterback (1997) argue that emerging technologies/innovations often substitute for more mature technologies/innovations. In this context, the evolution of technology can be characterized by a competition between new and old technology/innovation that generates technological change in society.
Second approach is based on recent theories that explain technological evolution by an interaction with other technologies/innovations. Pistorius and Utterback (1997, p. 67) argue that a multi-mode interaction between technologies/innovations provides a much richer theoretical framework for technology analysis (cf., Utterback et al., 2019). In this research field, a main interaction underlying the evolution of technologies and technological innovations is the technological parasitism proposed by Coccia (2018, 2019). In particular, Coccia (2019, 2018) purports that technologies can have a behavior similar to parasites (that find their ecological niche in a host system) because technologies and technological innovations cannot survive and develop as independent systems per se, but they can function and evolve if they are associated with other host or master technologies (such as, audio headphones, speakers, software apps, etc. that function if and only if they are associated with host or master electronic devices, e.g., smartphone, radio receiver, television, etc.). A parasitic technology within a host or master technology creates a complex system leading to coevolutionary processes to satisfy human needs and desires and/or solve problems in society. A technology/innovation can be a parasite of different host or master technologies, as well as a technology can be a host or master of different parasitic technologies (e.g., mobile devices are host of software applications, headphones, Bluetooth technology, etc.-indicated as parasitic technologies by Coccia, 2019, 2019a). 
Hence, technologies/innovations do not function as independent systems, but de facto they depend, as parasites, on other technologies (hosts or masters) to form a complex system of parts that interact in a non-simple way, generating a coevolution of host-parasite complex system. Main properties of the evolution of technologies and technological innovations are:
- theorem of not independence of any technology (Coccia, 2018b): the long-run behavior and evolution of any technological innovation is not independent from the behavior and evolution of the other technological innovations
- Property of mutual benefaction between technologies: the interaction between technologies reduces negative effects and favors positive effects directed to an evolution of reciprocal adaptations of technologies in volatile environments to satisfy needs and solve consequential problems of adopters (cf., Coccia, 2019, 2019a).
- Rapid evolution driven by manifold technological parasites: Technological host or master with many parasitic technologies generates a rapid stepwise evolution of technological host-parasite system. Technological systems with fewer parasitic technologies and a low level of interaction with other technologies improve slowly over time and space (Coccia and Watts, 2020).
Asymmetric shape of technological cycle: technological evolution of an innovation has an up wave phase longer than down wave phase (Coccia, 2020a).
Conclusion
References
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