The role of a teacher has evolved several times these days, including leader, lecturer, instructor, logistician, consultant, host, inspirer, master, and manager. These are all necessary roles at the scene of education from the perspective of Darwinism.
The Leader set up goals to guide students through suitable route toward effective and efficient knowledge gaining or success in the contest of academia. After that, some focus on knowledge copying from the lecturer toward the listener, while others prefer taking the role as an instructor to help students learn through materials such as books or videos on their own. To facilitate the whole education context, the logistician provides convenient facilities, and the consultant helps out once a problem emerges. Sometimes, interactive activities are hosted in the name of things like oral speaking practice, or just for fun. Learners are delicate souls easy to get frustrated, where inspirers come into play. To master, masters are needed in terms of secret tips or mantra. Along this journey, the notorious manager keeps a tab on everyone via tests and exams to ensure the correctness as well as secure proper academic performance.
Note. An instructor is a person whose job is to teach people a practical skill. cambridge reference.
Below are just Temporary Drafts
Later, because of the advance of the technology as well as the wealth, part of knowledge transmission were delegated to books, tapes or even videos. Teachers become instructors that help students develop self-guided learning ability. Some ingenious educationists proposed a third way of learning neither from the lecturer nor by themselves–the cooperative style. This way, teachers become hosts that help students participates in activities that help students learn inter-personal relationship and cooperation, as well as knowledge subliminally. Even better, sometimes the host teachers become inspirers to help students set up their own goal to explore for knowledge, while still on the track to success inside a certain academic field–as known as the approach of problem based learning. Finally, the role as a master gives the meta knowledge regarding the tips of how to do–the secret or mantra.
From the perspective of evolution, these roles are necessary for education since they have survived almost one hundred years, only that the recipe might differ from time to time.
Neo-Education
In addition to books, the lecture activities will be completely delegated to digital media because (a) the best lecturer can be accessed through internet and that people love high-quality lecture; (b) video media offer playback function so people have full control of their learning pace; (c) the cost of education and learning decreases while the efficiency increases dramatically. In that case, teachers have to perform as leaders to guide students through the path of interactive media, while still on the track to success inside certain field of academia. In this case, teachers will have plenty of time playing other roles onsite, e.g., hosting more activities or answering more questions.