Mental development is important when teaching any science including life sciences. Science, particularly human science, is unlike any other subject. An understanding of the fundamentals and facts is important. For this to happen, you must ensure that teachings provide mental stimulation and hit the students on a psychological level.
Scientific developments in human history are a fantastic teaching tool. History has a huge impact on what we do today. Learning about our scientific past improves our scientific literacy skills, makes us appreciate how far we have come and it is fun for everyone to learn that our ancient ancestors were totally inventive and smarter than we might have thought.
Systems in science are important. Organization is important in science and, to be honest, in most aspects of your life. Its how you make sense of the world.
Respect the importance of scientific literacy. Daily decisions on life, and our ability to converse intelligently is rooted in our basic science literacy.