Children, in order to truly understand the deep complexities of Nature, must be taught about every aspect of our environment, and gain a very strong foothold in science. Few things are what they seem. Even the simplest observations are not what they seem. Planets at night, to the untrained eye, are indistinguishable from stars billions of miles away. Cute animals are often dangerous, colorful ones, not only not toys, but poisonous.
Most plants are toxic, though beautiful to look at.
The truth is that the world as it really works is not obvious at all, and even though man has been observing and studying it since we were conscious enough to do so there is a lot we don't know. For example, there have been no exhaustive studies of a large ecosystem's biodiversity, giving us a complete knowledge of even a single environment's entire range of life. When we go in a bulldozer and clean an area of its plants and trees and wildlife, we're doing so with almost no knowledge of its affect on the rest of this planet's health. Most of our knowledge of life on this planet is disjoined, episodic, and limited by the way our brain evolved to keep us alive. If we wish life to continue on this planet, learning about our environment must be as important as learning about math, history, and all the other things we learn in school.