Rupert Sheldrake is best known for the introduction of the term Morphic Field and Resonance, which is an organizing field or systems which can be found at all levels of complexity.
Morphic Fields underlie the organisations of minds, bodies, crystals, plants, molecules, planets, solar systems, galaxies etc. They give things their shape, their form and their organisation.
The more thoughts, ideas and actions arise concerning a specific topic or field, the more powerful the morphic field becomes. Which in turn attracts more thoughts and interests from individuals, who then add to this virtual field or abstract thought construct.
Rupert Sheldrake writes in his book The Presence of the Past: "The morphic fields include all kinds of organizing fields...: The organizing fields of animal and human behaviour, of social and cultural systems, and of mental activity can all be regarded as morphic fields which contain an inherent memory."
This a rather large video, where he speaks about Morphic Fields and the Morphogenetic Universe:
The 100th Monkey Theory tells us how the behaviour of an entire group of individuals can change when the critical mass is reached. Allthough this popular story explains how a morphic field works, Sheldrake never uses it to confirm his theory.
Lyall Watson was the first to mention the 100th Monkey Theory in his book LIFETIDE (1979): In the early 1950ies, on the Japanese island of Koshima the Macaque monkeys were fed sweet potatoes by scientists who were observing their behaviour.
The scientist would feed these monkeys by throwing sweet potatoes into the sand. One young female monkey, named Imo, started washing the dirty sweet potatoes in the sea before eating them and discovered the improved flavours of washed potatoes.
Other young monkeys in her troop observed her and began doing the same. Soon all young monkeys washed their potatoes in the sea as well as their mothers. According to Lyall Watson, when the 100th monkey in the troop learned the new skill, over night all monkeys on the island began washing their potatoes before eating them. He goes on to say:
The article points out that the older individuals, who do not have a lot of contact to the young ones in their troop, would not adapt to the new skills. When the young ones reach adulthood, they teach the new skills to their offspring naturally and after a couple of generations the whole troop uses the new skills as a natural way of living.