Flexi Says: Fungi were classified in the plant kingdom until the 5 kingdom system was proposed in 1969 and eventually accepted. Prior to that, most scientists used only two kingdoms: plants and animals. Fungi were classified as plants due mostly to being sessile (non-moving) and growing in soil, like plants. Recent genetic evidence shows that fungi are actually more closely related to animals than to plants. Like animals, fungi are heterotrophs which cannot make their own food.